We continue our tradition and publish another article from the "testing methodology" series. Articles like this serve both as a general theoretical basis to help readers get an introduction to the topic, and as specific guidance for interpreting test results obtained in our laboratory. Today's article on the methodology will be somewhat unusual - we decided to devote a significant part of it to the theory of sound and acoustic systems. Why is this needed? The fact is that sound and acoustics are practically the most difficult of all topics covered by our resource. And, perhaps, the average reader is less savvy in this area than, say, in assessing the overclocking potential of various Core 2 Duo steppings. We hope that the reference materials that formed the basis of the article, as well as a direct description of the measurement and testing methodology, will fill in some gaps in the knowledge of all amateurs. good sound. So, let's start with the basic terms and concepts that any novice audiophile must know.
Basic terms and concepts
A little introduction to music
Let's start in an original way: from the beginning. From what sounds through the speakers, and about other headphones. It just so happened that the average human ear distinguishes signals in the range from 20 to 20,000 Hz (or 20 kHz). This fairly solid range, in turn, is usually divided into 10 octaves(you can divide by any other number, but 10 is accepted).
In general octave is the frequency range whose limits are calculated by doubling or halving the frequency. The lower limit of the next octave is obtained by doubling the lower limit of the previous octave. Anyone familiar with Boolean algebra will find this series strangely familiar. Powers of 2 with added zero at the end in pure form. Actually, why do you need knowledge of octaves? It is necessary in order to stop confusion about what should be called lower, middle or some other bass and the like. The generally accepted set of octaves uniquely determines who is who to the nearest hertz.
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Octave number |
Lower limit, Hz |
Upper limit, Hz |
Name |
Title 2 |
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deep bass |
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Medium bass |
Subcounter |
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upper bass |
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lower middle |
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Actually the middle |
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Upper middle |
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Lower top |
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Medium top |
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Upper high |
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Upper octave |
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The last line is not numbered. This is due to the fact that it is not included in the standard ten octaves. Pay attention to the column "Name 2". It contains the names of octaves that are distinguished by musicians. These "weird" people have no concept of deep bass, but there is one octave above - from 20480 Hz. Therefore, such a discrepancy in the numbering and names.
Now we can talk more specifically about the frequency range of acoustic systems. We should start with some bad news: there is no deep bass in multimedia acoustics. The vast majority of music lovers at -3 dB have simply never heard 20 Hz. And now the news is pleasant and unexpected. In a real signal, there are no such frequencies either (with some exceptions, of course). An exception is, for example, a recording from the IASCA Competition referee disc. The song is called "The Viking". There, even 10 Hz are recorded with a decent amplitude. This track was recorded in a special room on a huge organ. The system, which will play the Vikings, the judges hung with awards, like a Christmas tree with toys. And with a real signal, everything is simpler: a bass drum - from 40 Hz. Hefty Chinese drums - also from 40 Hz (there is, however, one mega-drum among them. So it starts playing from 30 Hz). Live double bass - generally from 60 Hz. As you can see, 20 Hz is not mentioned here. Therefore, you can not be upset about the absence of such low components. They are not needed to listen to real music.
The figure shows the spectrogram. There are two curves on it: purple DIN and green (from old age) IEC. These curves represent the spectrum distribution of the average musical signal. The IEC characteristic was used until the 60s of the 20th century. In those days, they preferred not to mock the squeaker. And after the 60s, experts drew attention to the fact that the preferences of listeners and music have changed somewhat. This was reflected in the standard of the great and mighty DIN. As you can see, there are much more high frequencies. But the bass did not increase. Conclusion: no need to chase super-bass systems. Moreover, the desired 20 Hz was not put in the box anyway.
Speaker Specifications
Now, knowing the ABC of octaves and music, you can begin to understand the frequency response. AFC (frequency response) - dependence of the oscillation amplitude at the output of the device on the frequency of the input harmonic signal. That is, the system is fed a signal at the input, the level of which is taken as 0 dB. From this signal, speakers with an amplifying path do what they can. It turns out they usually do not have a straight line at 0 dB, but in some way a broken line. The most interesting thing, by the way, is that everyone (from audio amateurs to audio manufacturers) strives for a perfectly flat frequency response, but they are afraid to "aspire".
Actually, what is the use of the frequency response and why do the authors of TECHLABS with enviable constancy try to measure this curve? The fact is that it can be used to establish real, and not whispered by the "evil marketing spirit" to the manufacturer, the boundaries of the frequency range. It is customary to indicate at what signal drop the cutoff frequencies are still played. If not specified, it is assumed that the standard -3 dB has been taken. This is where the trick lies. It is enough not to indicate at what drop the border values were taken, and you can absolutely honestly indicate at least 20 Hz - 20 kHz, although, indeed, these 20 Hz are achievable at a signal level that is very different from the prescribed -3.
Also, the benefit of the frequency response is expressed in the fact that, although approximately, it is possible to understand what problems the selected system will have. And the system as a whole. The frequency response suffers from all elements of the tract. To understand how the system will sound according to the schedule, you need to know the elements of psychoacoustics. In short, the situation is as follows: a person speaks within medium frequencies. Therefore, he perceives them the best. And on the corresponding octaves, the graph should be the most even, since distortions in this area put a lot of pressure on the ears. It is also undesirable to have high narrow peaks. The general rule here is that peaks are heard better than troughs, and a sharp peak is heard better than a flat one. We will dwell on this parameter in more detail when we consider the process of its measurement.
Phase response (PFC) shows the change in phase of the harmonic signal reproduced by the speaker depending on the frequency. It can be unambiguously calculated from the frequency response using the Hilbert transform. The ideal PFC, which says that the system has no phase-frequency distortion, is a straight line passing through the origin. Acoustics with such a phase response is called phase-linear. For a long time, this characteristic was ignored, since there was an opinion that a person is not susceptible to phase-frequency distortions. Now they measure and indicate in the passports of expensive systems.
Cumulative spectrum attenuation (CCD) - a set of axial frequency response (frequency response measured on the acoustic axis of the system), obtained with a certain time interval during the attenuation of a single pulse and reflected on one three-dimensional graph. Thus, according to the graph of the QLC, it is possible to say exactly which regions of the spectrum will decay at what rate after the pulse, that is, the graph allows you to identify delayed resonances of the speakers.
If the GLC has a lot of resonances after the upper middle, then such acoustics will subjectively sound "dirty", "with sand on the HF", etc.
AC impedance - this is the total electrical resistance of the AC, including the resistance of the filter elements (complex value). This resistance contains not only active resistance, but also reactances of capacitances and inductances. Since the reactance depends on the frequency, the impedance is also completely subordinate to it.
If one speaks of impedance as a numerical quantity completely devoid of complexity, then one speaks about its modulus.
Three-dimensional impedance graph (amplitude-phase-frequency). Usually, its projections on the amplitude-frequency and phase-frequency planes are considered. If you combine these two plots, you get the Bode plot. And the amplitude-phase projection is a Nyquist plot.
Given that the impedance is frequency dependent and not constant, it can be easily used to determine the complexity of the acoustics for the amplifier. Also, according to the schedule, you can tell what kind of acoustics it is (ZYa - a closed box), FI (with a phase inverter), how individual sections of the range will be reproduced.
Sensitivity - see Thiel-Small parameters.
Coherence - coordinated flow of several oscillatory or wave processes in time. It means that the signal from different GG acoustic systems will come to the listener at the same time, that is, it indicates the safety of phase information.
The meaning of the listening room
The listening room (often abbreviated to KdP among audiophiles), and its conditions are extremely important. Some put KDP in first place in importance, and only after it - acoustics, amplifier, source. This is somewhat justified, since the room is capable of doing anything with the graphs and parameters measured by the microphone. There may be peaks or dips in the frequency response that were not present in the measurements in the anechoic room. The PFC will also change (following the frequency response) and the transient characteristics. In order to understand where such changes come from, it is necessary to introduce the concept of room modes.
Room mods are beautifully named room resonances. The sound is emitted by the speaker system in all directions. Sound waves bounce off everything in the room. In general, the behavior of sound in a single listening room (LL) is completely unpredictable. There are, of course, calculations that allow us to evaluate the effect of various modes on sound. But they exist for an empty room with an idealized finish. Therefore, it is not worth bringing them here, they have no practical value in domestic conditions.
However, it is necessary to know that resonances and the reasons for their appearance directly depend on the frequency of the signal. For example, low frequencies excite room modes, which are determined by the size of the CDP. The boominess of the bass (resonance at 35-100 Hz) is a clear representative of the appearance of resonances in response to a low frequency signal in a standard room of 16-20 m 2. High frequencies give rise to slightly different problems: diffraction and interference of sound waves appear, which make the directional characteristic of the speaker frequency dependent. That is, the directivity of the speaker becomes narrower with increasing frequency. It follows from this that the listener will receive maximum comfort at the intersection of the acoustic axes of the speakers. And only he. All other points in space will receive less information or receive it distorted in one way or another.
The influence of the room on the speakers can be significantly reduced by dampening the CDP. To do this, various sound-absorbing materials are used - from thick curtains and carpets to special plates and tricky wall and ceiling configurations. The quieter the room, the more the speaker contributes to the sound, and not the reflections from your favorite computer desk and a pot of geraniums.
Recipes for arranging speakers in a room
Vandersteen recommends placing loudspeakers along the longest wall of the room at points where low frequency modes are least likely to occur. You need to draw a plan of the room. On the plan, divide a long wall into three, five, seven and nine parts in sequence, draw the corresponding lines perpendicular to this wall. Do the same with the side wall. The points of intersection of these lines will indicate those places where the excitation of low frequencies in the room is minimal.
Lack of bass, lack of tight and clear bass:
try moving the speakers closer to the back wall;
check if the speaker stands are stable: if necessary, use spikes or conical legs;
check how solid the wall behind the speakers is. If the wall is flimsy and "sounds", put the speakers in front of a powerful (capital) wall.
The stereo image does not go beyond the space limited by the speakers:
move the speakers closer to each other.
There is no depth of sound space. There is no clear sound image in the center between the speakers:
choose the optimal height of the speakers (use stands) and your listening position.
Harsh annoying sound in the mid and high frequencies:
if the speakers are new, warm them up on a music signal for a few days;
check for strong reflections from the side walls or from the floor in front of the listener.
distortion
It is necessary to move from subjectivism to technical concepts. Let's start with distortion. They are divided into two large groups: linear and non-linear distortions. Linear distortion do not create new spectral components of the signal, only change the amplitude and phase components. (They distort the frequency response and phase response, respectively.) Nonlinear distortion make changes to the spectrum of the signal. Their number in the signal is presented in the form of coefficients of non-linear distortion and intermodulation distortion.
THD (THD, THD - total harmonic distortion) is an indicator that characterizes the degree to which the voltage or current waveform differs from the ideal sinusoidal waveform. In Russian: a sine wave is applied to the input. At the output, it does not look like itself, since the path introduces changes in the form of additional harmonics. The degree of difference between the signal at the input and at the output is reflected by this coefficient.
Intermodulation distortion factor - this is a manifestation of amplitude nonlinearity, expressed in the form of modulation products that appear when a signal is applied, consisting of signals with frequencies f1 And f2(based on the IEC 268-5 recommendation, frequencies are taken for measurements f 1 and f 2, such that f 1 < f 2/8. You can take another ratio between frequencies). Intermodulation distortion is quantified by spectral components with frequencies f2±(n-1) f1, where n=2.3,… At the output of the system, the number of extra harmonics is compared and what percentage of the spectrum they occupy is estimated. The result of the comparison is the coefficient of intermodulation distortion. If measurements are carried out for several n (usually 2 and 3 are enough), then the final intermodulation distortion coefficient is calculated from the intermediate ones (for different n) by taking the square root of the sum of their squares.
Power
You can talk about it for a very long time, since there are many types of measured speaker powers.
A few axioms:
loudness does not depend only on power. It also depends on the sensitivity of the speaker itself. And for an acoustic system, the sensitivity is determined by the sensitivity of the largest speaker, since it is the most sensitive;
the indicated maximum power does not mean that you can apply it to the system and the speakers will play perfectly. Everything is just more annoying. Maximum power for a long time with a high probability of damaging something in the dynamics. Manufacturer's warranty! Power should be understood as an unattainable limit. Only less. Not equal and even more so - more;
little of! At maximum power or close to it, the system will play extremely poorly, because the distortion will grow to completely indecent values.
The power of the speaker system is electrical and acoustic. It is unrealistic to see the acoustic power on the box with acoustics. Apparently, in order not to scare away the client with a small number. The fact is that the efficiency (efficiency) of the GG (loudspeaker head) in a very good case reaches 1%. The usual value is up to 0.5%. Thus, acoustic power system ideally can be one hundredth of its electrical potential. Everything else is dissipated in the form of heat, spent on overcoming the elastic and viscous forces of the speaker.
The main types of power that can be seen on acoustics are: RMS, PMPO. This is electrical power.
RMS(Root Mean Squared - rms value) - the average value of the input electrical power. The power measured in this way has a semantic load. Measured by feeding a sine wave at a frequency of 1000 Hz, limited from above by a given value of THD (THD). It is imperative to study what level of non-linear distortion the manufacturer considered acceptable so as not to be deceived. It may be that the system is claimed to be 20 watts per channel, but the measurements were taken at 10% THD. As a result, it is impossible to listen to acoustics at this power. Also, at RMS power, the speakers can play for a long time.
PMPO(Peak Music Power Output - peak music output power). What is the use of a person knowing that his system can possibly carry a short, less than a second, low frequency sine with great power? However, manufacturers are very fond of this option. Indeed, on plastic speakers the size of a child's fist, there can be a proud figure of 100 watts. Healthy boxes of Soviet S-90s were not lying around! :) Oddly enough, such figures have a very distant relation to real PMPO. Empirically (based on experience and observation), you can get approximately real watts. Take Genius SPG-06 as an example (PMPO-120 Watts). It is necessary to divide the PMPO into 10 (12 watts) and 2 (the number of channels). The output is 6 watts, which is similar to the real figure. Once again: this method is not scientific, but based on the observations of the author. Usually works. In reality, this parameter is not so great, and the huge numbers are based only on the wild imagination of the marketing department.
Thiel-Small parameters
These parameters fully describe the speaker. There are parameters both constructive (area, mass of the moving system) and non-constructive (which follow from the constructive ones). There are only 15 of them. In order to roughly imagine what kind of speaker works in the column, four of them are enough.
Speaker resonant frequency fs(Hz) - the resonance frequency of the speaker, operating without acoustic design. Depends on the mass of the moving system and the rigidity of the suspension. It is important to know, since the speaker practically does not sound below the resonant frequency (the sound pressure level drops strongly and sharply).
Equivalent Volume Vas(liters) - the useful volume of the case required for the operation of the speaker. Depends only on the area of the diffuser (Sd) and the flexibility of the suspension. It is important because, while working, the speaker relies not only on the suspension, but also on the air inside the box. If the pressure is not what you need, then you will not see the ideal operation of the speaker.
Full quality factor Qts- the ratio of elastic and viscous forces in the moving system of the speaker near the resonance frequency. The higher the quality factor, the higher the elasticity in the dynamics and the more willingly it sounds at the resonant frequency. It consists of mechanical and electrical quality factors. Mechanical - this is the elasticity of the suspension and the corrugation of the centering washer. As usual, but it is the corrugation that provides greater elasticity, and not external suspensions. Mechanical quality factor - 10-15% of full quality factor. Everything else is an electrical quality factor formed by a magnet and a speaker coil.
DC resistance Re(Ohm). There is nothing special to explain here. Head winding resistance to direct current.
Mechanical quality factor Qms- the ratio of elastic and viscous forces of the speaker, elasticity is considered only the mechanical elements of the speaker. It consists of the elasticity of the suspension and the corrugation of the centering washer.
Electrical quality factor Qes- the ratio of elastic and viscous forces of the speaker, elastic forces arise in the electrical part of the speaker (magnet and coil).
diffuser area SD(m 2) - measured, roughly speaking, with a ruler. It has no secret meaning.
Sensitivity SPL(dB) - the sound pressure level developed by the loudspeaker. Measured at a distance of 1 meter with an input power of 1 watt and a frequency of 1 kHz (typically). The higher the sensitivity, the louder the system plays. In a two-way or more-way system, the sensitivity is equal to the SPL of the most sensitive speaker (usually a bass mug).
Inductance Le(Henry) is the inductance of the speaker coil.
Impedance Z(Ohm) - a complex characteristic that appears not on direct current, but on alternating current. The fact is that in this case, the reactive elements suddenly begin to resist the current. The resistance depends on the frequency. Thus, impedance is the ratio of the complex voltage amplitude and the complex current strength at a certain frequency. (Complex impedance depending on frequency, in other words).
Peak power Pe(Watt) is the PMPO discussed above.
Mass of the moving system mms(d) is the effective mass of the moving system, which includes the mass of the diffuser and the air oscillating with it.
Relative stiffness cms(meters/newton) - the flexibility of the movable system of the loudspeaker head, displacement under the influence of a mechanical load (for example, a finger that aims to poke the speaker). The higher the setting, the softer the suspension.
Mechanical resistance rms(kg/s) - active mechanical resistance of the head. Everything that can provide mechanical resistance in the head is included here.
Motor power BL- the value of the magnetic flux density multiplied by the length of the wire in the coil. Also, this parameter is called the force factor of the speaker. We can say that this is the power that will act on the diffuser from the side of the magnet.
All of these parameters are closely related. This is pretty obvious from the definitions. Here are the main dependencies:
fs increases with an increase in the rigidity of the suspension and decreases with an increase in the mass of the moving system;
Vas decreases with increasing suspension stiffness and increases with increasing diffuser area;
Qts increases with an increase in the stiffness of the suspension and the mass of the moving system and decreases with an increase in power BL.
So, now you are familiar with the basic theoretical apparatus necessary to understand articles on acoustic systems. Let's proceed directly to the testing methodology used by the authors of our portal.
Test Methodology
AFC. Measurement technique and interpretation
At the beginning of this section, we will deviate a little from the main topic and explain why all this is being done. First, we want to describe our own frequency response measurement method so that the reader does not have additional questions. Secondly, we will describe in detail how to perceive the obtained graphs and what can be said from the given dependencies, and also what should not be said. To start the methodology.
Measuring microphone Nady CM-100
Our frequency response measurement technique is quite traditional and differs little from the generally accepted principles for conducting detailed experiments. Actually the complex itself consists of two parts: hardware and software. Let's start with a description of the real devices that are used in our work. As a measurement microphone, we use a Behringer ECM-8000 high-precision condenser microphone with a circular pattern (omnidirectional), at a relatively low price, it has quite good parameters. So to speak, this is the "heart" of our system. This tool is designed specifically for use with modern technology as part of budget measuring laboratories. We also have a similar Nady CM-100 microphone at our disposal. The characteristics of both microphones are almost the same each other, however, we always indicate with which microphone this or that frequency response was measured. For example, here are the declared technical characteristics of the Nady CM-100 microphone:
impedance: 600 ohms;
sensitivity: -40dB (0dB=1V/Pa);
frequency range: 20-20000 Hz;
maximum sound pressure: 120 dB SPL;
power supply: phantom 15 ... 48 V.
Frequency response of the measuring microphone
M-Audio AudioBuddy Mic Preamp
As a microphone preamplifier, we use an external compact M-audio solution audiobuddy. The AudioBuddy preamp is designed specifically for digital audio applications and is optimized for microphones that require phantom power. Plus, the user has independent outputs: balanced or unbalanced TRS. The main parameters of the preamplifier are as follows:
frequency range: 5-50,000 Hz;
microphone gain: 60 dB;
input impedance of the microphone input: 1 kOhm;
instrument gain: 40 dB;
instrument input impedance: 100 kOhm;
power supply: 9 V AC, 300 mA.
Sound card ESI [email protected]
For further analysis, the signal from the output of the amplifier is fed to the input of a computer audio interface, which is an ESI PCI card. [email protected] This solution can be safely attributed to the class of semi-professional devices or even entry-level professional ones. Main parameters:
number of I/O: 4 inputs (2 analog, 2 digital), 6 outputs (2 analog, 4 digital);
ADC/DAC: 24-bit/192 kHz;
frequency response: 20 Hz - 21 kHz, +/- 0.5 dB;
dynamic range: ADC 114 dB, DAC 112 dB;
inputs: 2 analog, 2 digital (S/PDIF Coaxial);
outputs: 2 analog, 2 digital (S/PDIF Coaxial or Optical);
MIDI: 1 MIDI in and 1 MIDI out
interface: PCI;
sync: MTC, S/PDIF;
Drivers: EWDM driver support for Windows 98SE/ME/2000 and XP, MAC OS 10.2 or older.
In general, the unevenness of the path of the entire system in the frequency range of 20-20000 Hz lies within +/- 1 ... 2 dB, so our measurements can be considered quite accurate. The main negative factor is that all measurements are taken in an average living room with standard reverberation. The area of the room is 34 m 2 , the volume is 102 m 3 . The use of an anechoic chamber, of course, increases the accuracy of the result, but the cost of such a chamber is at least several tens of thousands of dollars, so only large manufacturers of acoustic systems or other very wealthy organizations can afford such a "luxury". However, there are tangible advantages in this: for example, the frequency response in a real room will always be far from the frequency response, which was obtained by the manufacturer in the test chamber. Therefore, based on our results, we can draw some conclusions about the interaction of specific acoustics with the average room. This information is also very valuable, because any system will be operated in real conditions.
Popular utility rightmark Audio Analyzer
The second important point is software part. We have several professional software packages at our disposal, such as RightMark Audio Analyzer ver. 5.5 (RMAA), TrueRTA ver. 3.3.2, LSPCad ver. 5.25, etc. As a rule, we use the convenient RMAA utility, provided that it is distributed free of charge and constantly updated, it is very practical and provides high measurement accuracy. In fact, it has already become the standard among test packages throughout the RuNet.
Program TrueRTA
Measuring module JustMLS programs LSPCad
It would seem that any measurement should be carried out according to strictly established rules, but in the field of acoustics there are too many of these rules, and often they differ somewhat from each other. For example, the basic norms and methods of measurement are given in several very weighty documents at once: outdated GOST USSR (GOST 16122-87 and GOST 23262-88), IEC recommendations (publications 268-5, 581-5 and 581-7), German standard DIN 45500, as well as US regulations AES and EIA.
We make our measurements in the following way. The acoustic system (AC) is installed in the center of the room at the maximum distance from walls and bulky objects, a high-quality stand 1 m high is used for installation. The microphone is installed at a distance of about a meter on a straight axis. The height is chosen so that the microphone "looks" approximately at the center point between the midrange and tweeters. The resulting frequency response is called a characteristic taken on a straight axis, and in classical electroacoustics it is considered one of the most important parameters. It is believed that the fidelity of reproduction directly depends on the uneven frequency response. However, read about it below. We also always measure the angular characteristics of the system. In the ideal case, it is necessary to obtain a whole set of dependencies in the vertical and horizontal planes with a step of 10 ... 15 degrees. Then it is quite reasonable to draw conclusions about the speaker pattern, give advice on the correct arrangement in space. In fact, the angular frequency response is no less important than the straight-axis frequency response, since they determine the nature of the sound reaching the listener after reflection from the walls of the room. According to some reports, the proportion of reflections at the listening point reaches 80% or more. We also film everything. possible characteristics path with all available frequency adjustments, 3D-type modes, etc.
Simplified block diagram of the measurement process
You can tell a lot from these charts...
Subjective Listening
So, the frequency response graphs are received. What can be said by studying them in detail? In fact, much can be said, but it is impossible to unambiguously evaluate the system according to these dependencies. Not only is the frequency response not a very informative characteristic, and a number of additional measurements are required, for example, impulse response, transient response, cumulative attenuation of the spectrum, etc., it is rather difficult to give an unambiguous assessment of acoustics even using these exhaustive dependencies. Strong evidence of this is the official statement by AES (Journal of AES, 1994) that a subjective assessment is simply necessary to get a complete picture of the loudspeaker in addition to objective measurements. In other words, a person can hear a certain artifact, and it is possible to understand where it comes from only after a series of accurate measurements. Sometimes measurements help to identify an insignificant flaw that can easily slip past your ears when listening, and you can “catch” it only by focusing your attention on this particular range.
To begin with, it is necessary to break the entire frequency range into characteristic sections so that it is clear what is at stake. Agree, when we say "mid frequencies", it's not clear how much it is: 300 Hz or 1 kHz? Therefore, we suggest using the convenient breakdown of the entire sound range into 10 octaves, described in the previous section.
Finally, we pass directly to the moment of the subjective description of the sound. There are thousands of terms for evaluating what is heard. The best option is to use some documented system. And there is such a system, it is offered by the most authoritative publication with a half-century history of Stereophile. Relatively recently (in the early 90s of the last century), the Audio Glossary was published under the editorship of Gordon Holt. The dictionary contains an interpretation of more than 2000 concepts that in one way or another relate to sound. We suggest that you familiarize yourself with only a small part of them, which refers to the subjective description of sound in the translation of Alexander Belkanov (Magazine "Salon AV"):
ah-ax (rhymes with "rah" - Hurrah). Vowel coloring caused by a peak in the frequency response in the region of 1000 Hz.
Airy - airiness. Refers to high frequencies, sounding light, gentle, open, with a feeling of unlimited top. The property of a system that has a very flat response at high frequencies.
aw - (rhymes with "paw" [po:] - paw). Vowel coloring caused by a peak in the frequency response around 450 Hz. Seeks to emphasize, embellish the sound of large brass (trombone, trumpet).
Boomy - Read the word "boom" with a long "m". Characterizes an excess of middle bass, often with a predominance of a narrow bass band (very close to "one-note-bass" - bass on one note).
Boxy (literally - "box"): 1) characterized by "oh" - the color of vowels, as if the head is talking inside the box; 2) is used to describe the upper bass/lower mids of speakers with excessive cabinet wall resonances.
Bright, brilliant - bright, shiny, sparkling. An often misused term in audio, it describes the degree of hardness of the edge of the reproduced sound. Luminance refers to the energy contained in the 4-8 kHz band. This does not apply to most high frequencies. All living sounds have brightness, the problem arises only when it is redundant.
Buzz - a buzzing low-frequency sound that has a fluffy or spiky character due to some uncertainty.
Chesty - from chest (chest). A pronounced density or heaviness in the reproduction of a male voice due to excessive energy in the upper bass / lower midrange.
Closed-in (literally - hidden, closed). Needs openness, air and good detail. Closed sounding is usually caused by high-frequency roll-off above 10 kHz.
Cold - cold, stronger than cool - cool. It has some excess highs and weakened lows.
Coloration - coloring. The audible "signature" with which a reproducing system colors all signals passing through it.
Cool - cool. Moderately devoid of density and warmth due to monotonous decay starting at 150 Hz.
Crisp - crisp, well-defined. Accurately localized and detailed, sometimes excessive due to a peak in the middle of the high range.
Cupped-hands - a mouthpiece from the palms. Coloring with nasal overtones or in extreme manifestation - sound through a megaphone.
Dark - dark, gloomy (literally). Warm, soft, overly rich sound. Perceived by ear as a clockwise slope of the frequency response over the entire range, so that the output level is attenuated with increasing frequency.
Dip (literally - immersion, failure). A narrow dip in the middle of a flat frequency response.
Discontinuity (literally - gap). Change in timbre or color when a signal passes from one head to another in multi-band acoustic systems.
Dished, dished-down - in the form of a saucer, an inverted saucer. Describes the frequency response with a failed mid. There is a lot of bass and treble in the sound, the depth is exaggerated. Perception is usually lifeless.
Dry (literally - dry). Describes the quality of the bass: lean, lean, usually overdamped.
Dull (literally - dull, dull, boring, lethargic, depressed). Describes a lifeless, veiled sound. Same as "soft" - soft, but to a greater extent. Audible high-frequency roll-off effect after 5 kHz.
her - rhymes with we. Vowel coloring caused by a peak in the frequency response around 3.5 kHz.
eh - as in "bed". Vowel coloration caused by a short rise in frequency response around 2 kHz.
Extreme highs - ultra high. The range of audible frequencies is above 10 kHz.
Fat (literally - plentiful, rich, fatty, oily). An audible effect of moderate redundancy in the middle and upper bass. Too warm, more "warm".
Forward, forwardness (literally - brought to the fore, forwardness). Playback quality that gives the impression that sound sources are closer than they were when recorded. As a rule, this is the result of a "hump" in the middle range plus a narrow directionality of the speakers.
Glare (literally - dazzling, sparkling). Unpleasant quality of hardness or brightness due to excessive energy in the lower or middle top.
Golden (literally - golden). A euphonious color characterized by roundness, richness, melodiousness.
Hard (literally - hard, hard). Aspiring to steel, but not so piercing. This is often the result of a moderate "hump" around 6 kHz, sometimes caused by slight distortion.
Horn sound - a horn sound made through a horn. The "aw" coloring found in many loudspeakers that have a midrange horn driver.
Hot (literally - hot). Sharp resonant surge at high frequencies.
Hum (literally - buzzing). Continuous "itching" at frequencies that are multiples of 50 Hz. Caused by the penetration of the main power frequency or its harmonics into the playback path.
Humped (literally - hunched). Characterizes the sound pushed forward (according to the spatial characteristic). The overall sound is sluggish, poor. Caused by a wide rise in the mids and a fairly early roll-off of lows and highs.
ih - as in the word "bit". Vowel coloring caused by a peak in the frequency response around 3.5 kHz.
Laid-back (literally - pushed back, pushed back). Suppressed, distant sound, with exaggerated depth, usually due to a dip in the middle range in the form of a saucer.
Lean - thin, skinny, frail. The effect of a weak decline in the frequency response down, starting from 500 Hz. It is less pronounced than "cool" - cool.
Light - light. The audible effect of tilting the frequency response counterclockwise from the middle. Compare with "dark" - dark.
Loose - loose, dangling, unstable. Refers to poorly defined/blurred and poorly controlled bass. Amplifier damping or driver/loudspeaker styling issues.
Lumpy (literally - lumpy). A sound characterized by some discontinuity in the frequency response in the lower part, starting from 1 kHz. Some areas appear to be bulging, others seem to be weakened.
Muffled - muted. Sounding very sluggish, dull, not having high frequencies at all. The result of high frequency rolloff above 2 kHz.
Nasal (literally - nasal, nasal). The sound is similar to speaking with a stuffy or blocked nose. Similar to the coloration of the vowel "eh". In loudspeakers, this is often caused by a measurable pressure peak in the upper midrange followed by a subsequent dip.
oh - pronunciation as in the word "toe". Vowel coloration caused by a wide frequency response peak around 250 Hz.
One-note-bass - bass on one note. The predominance of one low note is a consequence of a sharp peak in the lower range. Usually caused by poor damping of the woofer, room resonances can also appear.
oo - pronunciation as in the word "gloom". The color of the vowel is caused by a wide peak in the frequency response around 120 Hz.
Power range - maximum energy range. The frequency range of approximately 200-500 Hz corresponds to the range of powerful orchestra instruments - brass.
Presence range (literally - presence range). The lower part of the upper range is approximately 1-3 kHz, creating a sense of presence.
Reticent (literally - restrained). Moderately pushed back. Describes the sound of a system whose frequency response is saucer-shaped in the midrange. The opposite of forward.
Ringing (literally - ringing). Audible resonance effect: coloration, smeared/blurred sound, shrillness, buzz. It has the nature of a narrow peak in the frequency response.
Seamless (literally - without a seam, from a single / solid piece). It has no perceptible breaks in the entire audible range.
Seismic - seismic. Describes bass reproduction that makes the floor appear to be shaking.
Sibilance (literally - whistle, hiss). A coloring that emphasizes the vocal "s" sound. It can be associated with a monotonous rise in the frequency response from 4-5 kHz or with a wide overshoot in the 4-8 kHz band.
Silvery - silvery. Somewhat harsh, but clear sounding. Flute, clarinet, alto gives definition, but the gong, bells, triangle can communicate obsession, excessive harshness.
Sizzly - hissing, whistling. Raising the frequency response around 8 kHz, adding hiss (whistling) to all sounds, especially to the sound of cymbals and hissing in vocal parts.
Sodden, soggy (literally - wet, swollen with water). Describes loose and poorly defined bass. Creates a feeling of ambiguity, illegibility in the lower range.
Solid-state sound - transistor sound, semiconductor sound. Combination sound qualities common to most solid state amps: deep, tight bass, slightly pushed back bright stage character, and crisp, detailed highs.
Spitty (literally - spitting, snorting, hissing). The sharp "ts" is a coloring that unnecessarily emphasizes musical overtones and sizzles. Similar to surface noise vinyl record. Usually, the result is a sharp peak in the frequency response in the extreme high frequencies.
Steely - steel, steely. Describes shrillness, sharpness, importunity. Like "hard", but more so.
Thick - fat, thick, dull. Describes wet/dull or bulky, heavy bass.
Thin - liquid, frail, thin. Very lacking in bass. The result of a strong, monotonous downward decay starting at 500 Hz.
Tizzy (literally - excitement, anxiety), "zz" and "ff" - the coloring of the sound of cymbals and vocal hissing, caused by an increase in frequency response above 10 kHz. Similar to "wiry", but at higher frequencies.
Tonal quality - tonal quality. The precision/correctness with which the reproduced sound reproduces the timbres of the original instruments. (It seems to me that this term will be a good substitute for timbre resolution - A.B.).
Tube sound, tubey - sound due to the presence of tubes in the recording / playback path. The combination of sound qualities: richness (richness, liveliness, brightness of colors) and warmth, an excess of medium and a lack of deep bass. A bulging image of the scene. Tops are smooth and thin.
Wiry - hard, tense. Causes irritation with distorted high frequencies. Similar to brushes striking cymbals, but capable of coloring all the sounds produced by the system.
Wooly - sluggish, vague, shaggy. Refers to a dangling, loose, ill-defined bass.
Zippy - lively, fast, energetic. Slight emphasis on upper octaves.
So, now, looking at the given frequency response, you can characterize the sound with one or more terms from this list. The main thing is that the terms are systemic, and even an inexperienced reader can, by looking at their meaning, understand what the author wanted to say.
On what material are the acoustics tested? When choosing a test material, we were guided by the principle of diversity (after all, everyone uses acoustics in completely different applications - cinema, music, games, not to mention different tastes in music) and the quality of the material. In this regard, a set of test disks traditionally includes:
DVDs with movies and concert recordings in DTS and DD 5.1 formats;
discs with games for PC and Xbox 360 with high-quality soundtracks;
high-quality recorded CDs with music of various genres and directions;
MP3 discs with compressed music, material that is mainly heard on MM speakers;
special audiophile-quality test CDs and HDCDs.
Let's take a closer look at the test disks. Their purpose is to identify the shortcomings of acoustic systems. Allocate test disks with a test signal and with musical material. Test signals are generated reference frequencies (allow you to determine the boundary values of the reproducible range by ear), white and pink noise, a signal in phase and antiphase, and so on. The most interesting to us seem to be the popular test disk FSQ (Fast Sound Quality) and Prime Test CD . Both of these discs, in addition to artificial signals, contain fragments of musical compositions.
The second category includes audiophile discs containing entire compositions recorded in studios of the highest quality and precision mixed. We use two licensed HDCDs (recorded at 24 bits and 88 kHz) - Audiophile Reference II (First Impression Music) and HDCD Sampler (Reference Recordings), as well as the Reference Classic CD sampler of classical music from the same label Reference Recordings .
Audiophilereference II(the disc allows you to evaluate such subjective characteristics as musical resolution, involvement, emotionality and presence effect, the depth of the nuances of the sound of various instruments. The musical material of the disc is classical, jazz and folk works recorded with the highest quality and produced by the famous sound wizard Winston Ma. On the recording you can meet magnificent vocals, powerful Chinese drums, deep string bass and get real listening pleasure on a really high-quality system.
HDCDsampler from Reference Recordings contains symphonic, chamber and jazz music. Using the example of his compositions, one can track the ability of acoustic systems to build a musical stage, to convey macro- and micro-dynamics, the naturalness of the timbres of various instruments.
referenceClassic shows us the real forte of Reference Recordings - chamber music recordings. The main purpose of the disk is to test the system for the correct reproduction of various timbres and the ability to create the correct stereo effect.
Z-characteristic. Measurement technique and interpretation
Surely even the most inexperienced reader knows that any dynamic head, and, consequently, the speaker system as a whole, has a constant resistance. This resistance can be regarded as resistance to direct current. For household equipment, the most familiar numbers are 4 and 8 ohms. In automotive technology, speakers with a resistance of 2 ohms are often found. The impedance of good monitor headphones can reach hundreds of ohms. From the point of view of physics, this resistance is due to the properties of the conductor from which the coil is wound. However, speakers, like headphones, are designed to work with alternating current audio frequency. It is clear that with a change in frequency, the complex resistance also changes. The dependence characterizing this change is called the Z-characteristic. The Z-characteristic is quite important to study, because it is with the help of it that one can draw unambiguous conclusions about the correct matching of the speaker and amplifier, the correct calculation of the filter, etc. To remove this dependence, we use the LSPCad 5.25 software package, or rather, the JustMLS measuring module. Its capabilities are:
MLS size (Maximum-Length Sequence): 32764,16384,8192 and 4096
FFT (Fast Fourier Transform) size: 8192, 1024 and 256 points, used in different frequency bands
Sample rate: 96000, 88200, 64000, 48000, 44100, 32000, 22050, 16000, 1025, 8000 Hz and user selectable Custom (Select).
Window: Half Offset
Internal representation: 5 Hz to 50000 Hz, 1000 frequency points with logarithmic frequency.
To measure, you need to assemble a simple circuit: a reference resistor (in our case C2-29V-1) is connected in series from the speakers, and the signal from this divider is fed to the input of the sound card. The whole system (speaker / speaker + resistor) is connected through an AF power amplifier to the output of the same sound card. We use the ESI interface for this purpose. [email protected] The program is very convenient because it does not require careful and lengthy settings. It is enough to calibrate the sound levels and press the "Measure" button. In a fraction of a second, we see the finished chart. Further, it is analyzed, in each case we pursue different goals. So, when studying a low-frequency speaker, we are interested in the resonant frequency to check the correct choice of acoustic design. Knowing the resonant frequency of the high-frequency head allows you to analyze the correctness of the crossover filter solution. In the case of passive acoustics, we are interested in the characteristic as a whole: it should be as linear as possible, without sharp peaks and dips. So, for example, acoustics, the impedance of which sags below 2 ohms, will be "not to the taste" of almost any amplifier. Such things should be known and considered.
Nonlinear distortion. Measurement technique and interpretation
Nonlinear distortions (Total Harmonic Distortion, THD) are the most important factor when evaluating loudspeakers, amplifiers, etc. This factor is due to the nonlinearity of the path, as a result of which additional harmonics appear in the signal spectrum. The harmonic distortion factor (THD) is calculated as the ratio of the square of the fundamental harmonic to the square root of the sum of the squares of the additional harmonics. As a rule, only the second and third harmonics are taken into account in calculations, although accuracy can be improved by taking into account all additional harmonics. For modern acoustic systems, the coefficient of non-linear distortion is normalized in several frequency bands. For example, for the zero complexity group according to GOST 23262-88, the requirements of which significantly exceed the minimum requirements of the IEC Hi-Fi class, the coefficient should not exceed 1.5% in the frequency band 250-2000 Hz and 1% in the band 2-6.3 kHz. Dry figures, of course, characterize the system as a whole, but the phrase "SOI = 1%" still says little. A vivid example: a tube amplifier with a THD of about 10% can sound much better than a transistor amplifier with the same coefficient of less than 1%. The fact is that the distortion of the lamp is mainly due to those harmonics that are screened by the auditory adaptation thresholds. Therefore, it is very important to analyze the spectrum of the signal as a whole, describing the values of certain harmonics.
This is how the signal spectrum of a particular acoustics looks like at a control frequency of 5 kHz
In principle, you can see the distribution of harmonics over the spectrum with any analyzer, both hard and soft. The same RMAA or TrueRTA programs do this without any problems. As a rule, we use the first one. The test signal is generated using a simple generator, several control points are used. So, for example, non-linear distortions increased at high frequencies significantly reduce the microdynamics of the musical image, and a system with high distortions as a whole can simply greatly distort the timbre balance, wheeze, have extraneous overtones, etc. Also, these measurements make it possible to evaluate the acoustics in more detail in combination with other measurements, to check the correctness of the calculation of crossover filters, because the nonlinear distortions of the speaker increase greatly outside its operating range.
Article structure
Here we describe the structure of the article on acoustic systems. Although we try to make reading as pleasant as possible and do not squeeze ourselves into a certain framework, the articles are written with this plan in mind, so that the structure is clear and understandable.
1. Introduction
It is written here general information about the company (if we get to know it for the first time), general information about the product line (if we take it for the first time), we give an outline of the current market situation. If the previous options do not fit, we write about trends in the acoustics market, in design, etc. - so that 2-3 thousand characters are written (hereinafter - k). The type of acoustics is indicated (stereo, surround sound, triphonic, 5.1, etc.) and positioning on the market - as a multimedia game for a computer, universal, for listening to music for an entry-level home theater, passive for a home theater, etc.
Tactical and technical characteristics, summarized in the table. Before the table with TTX, we make a small introduction (for example, "we have the right to expect serious YYY parameters from acoustics costing XXX"). The table view and the set of parameters are as follows:
For systems2.0
|
Parameter |
Meaning |
|
Output power, W (RMS) |
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|
Speaker external dimensions, WxDxH, mm |
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|
Gross weight, kg |
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Net weight, kg |
|
|
Speaker diameter, mm |
|
|
Speaker impedance, Ohm |
|
|
Supply voltage, V |
|
|
Frequency range, Hz |
|
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Frequency response unevenness in the operating range, +/- dB |
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|
Bass control, dB |
|
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Crosstalk, dB |
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Signal-to-noise ratio, dB |
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|
Completeness |
|
|
Average retail price, $ |
For systems2.1
|
Parameter |
Meaning |
|
Satellite output power, W (RMS) |
|
|
SOI at rated power, % |
|
|
External dimensions of satellites, WxDxH, mm |
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Gross weight, kg |
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Net weight of satellites, kg |
|
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Subwoofer net weight, kg |
|
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Speaker diameter, mm |
|
|
Speaker impedance, Ohm |
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|
Magnetic shielding, availability |
|
|
Supply voltage, V |
|
|
Adjustment of high frequencies, dB |
|
|
Bass control, dB |
|
|
Crosstalk, dB |
|
|
Signal-to-noise ratio, dB |
|
|
Completeness |
|
|
Average retail price, $ |
For 5.1 systems
|
Parameter |
Meaning |
|
Output power of front satellites, W (RMS) |
|
|
Output power of rear satellites, W (RMS) |
|
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Output power of the central channel, W (RMS) |
|
|
Subwoofer output power, W (RMS) |
|
|
Total output power, W (RMS) |
|
|
SOI at rated power, % |
|
|
External dimensions of the front satellites, WxDxH, mm |
|
|
External dimensions of the rear satellites, WxDxH, mm |
|
|
External dimensions of the central channel, WxDxH, mm |
|
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External dimensions of the subwoofer, WxDxH, mm |
|
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Gross weight, kg |
|
|
Net weight of front satellites, kg |
|
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Net weight of rear satellites, kg |
|
|
Net weight of the central channel, kg |
|
|
Subwoofer net weight, kg |
|
|
Speaker diameter, mm |
|
|
Speaker impedance, Ohm |
|
|
Magnetic shielding, availability |
|
|
Supply voltage, V |
|
|
Frequency range of satellites, Hz |
|
|
Subwoofer frequency range, Hz |
|
|
Frequency response unevenness in the full operating range, +/- dB |
|
|
Adjustment of high frequencies, dB |
|
|
Bass control, dB |
|
|
Crosstalk, dB |
|
|
Signal-to-noise ratio, dB |
|
|
Completeness |
|
|
Average retail price, $ |
We take the given tables as a basis, if there is additional data, we make more columns, the columns for which there is no data, we simply remove them. After the table with performance characteristics, small preliminary conclusions.
3. Packaging and equipment
We describe the delivery set and the box, at least two photos. Here we evaluate the completeness of the kit, describe the nature of the cables included in the kit, if possible, evaluate their cross section / diameter. We make a conclusion about the compliance of the set with the price category, convenience and design of the package. We note the presence of a Russian-language instruction manual, its completeness.
4. Design, ergonomics and functionality
We describe the first impression of the design. We note the nature of the materials, their thickness, quality factor. We evaluate design decisions in terms of potential impact on sound (don't forget to add the word "presumably"). We evaluate the workmanship, the presence of legs / spikes, grill / acoustic fabric in front of the diffusers. We are looking for fasteners, the ability to install on a rack / shelf / wall.
Ergonomics and impressions of working with acoustics (excluding listening) are described. There is a click when turned on, whether the length of the wires is sufficient, whether it is convenient to use all controls. Implementation of controls (analogue sliders or "knobs", digital knobs, toggle switches, etc.) Several photos of controls, remote control if available, photos of speakers in an environment or in comparison with ordinary objects. Convenience and speed of switching, the need to check the phasing, whether the instruction helps, etc. We note the effectiveness of magnetic shielding (on a CRT monitor or TV). We pay attention to additional inputs, operating modes (pseudo-surround sound, built-in FM tuner, etc.), service capabilities.
5. Design
We disassemble the speakers, if there is a subwoofer, then also it. We note the following design features:
Type of acoustic design (open, closed box, phase inverter, passive radiate, transmission line, etc.) + general photo of the internal structure;
The dimensions and internal volume of the case, suggest the compatibility of AO with GG;
The location of the loudspeaker heads (GG), the method of attachment to the acoustic design;
Quality of internal installation, assembly, fastening + 1-2 photos with internal installation details;
The presence of mechanical damping, the quality of its execution and the materials used + photo;
The shape and dimensions of the phase inverter (if any), its location (probable effect on sound) and the manufacturer's likely devices to eliminate jet noise + photo;
The quality of internal wiring, the presence of overload protection, suggestions for modernization;
Used GG - type, material of manufacture (paper, impregnated silk, aluminum, plastic, etc.), nature of the diffuser surface (conical, exponential surface, corrugated, with "stiffeners", etc.) and protective cap (flat , "acoustic bullet", etc.), suspension (rubber, paper, etc.), degree of suspension rigidity), coil diameter, tweeter cooling, marking, resistance + photo of each GG;
Type of fastening of the wire to the speakers (separless, screw clamps, spring clamps, under the "banana", etc.) + photo;
Signal cable connectors - types, quantity, workmanship.
With diagrams and graphs, we illustrate the following things:
Amplifying microcircuit (s) - a table with key characteristics, their analysis for compliance with performance characteristics and speakers, if possible - give a graph of the dependence of power on SOI and a photo, you can have a photo of the radiator;
Power transformer - a table with currents, the type of transformer (torus, on W-shaped plates, etc.) indicating the total power in VA, conclusions about the presence of a supply power reserve, the presence of a power filter, etc. + photo;
Separation filter - we sketch the circuit, indicate the order of the filter (and, accordingly, the signal attenuation), we conclude that it is justified; applications (in the presence of appropriate measurements), we calculate the cutoff frequency in the event that in the future we measure the resonance and / or Z-characteristic;
We make a calculation of the resonant frequency of the phase inverter, give the formula and justify its use.
6. Measurements
We make the following measurements and provide an analysis for each of them, make assumptions about the nature of the sound.
Axial frequency response of the column with detailed analysis;
Frequency response of speakers at angles of 30 and 45 degrees, analysis of the nature of the dispersion of the speaker;
Subwoofer frequency response (if any) + total system frequency response, quality analysis; matching triphonics, the effect of phase inverter resonance;
Axial frequency response depending on the tone controls (if any);
Frequency response of a phase inverter, analysis;
The spectrum of harmonic distortion;
The frequency response of the speakers separately (for example, bass and treble), if necessary.
7. Audition
First, we give the first subjective assessment of the nature of the sound, indicate whether the volume is sufficient for various playback modes. We note the features of the acoustics in each of the typical applications - cinema (for 5.1 systems we focus on the quality of positioning), music and games. We indicate the type of room for listening, its area and volume, as well as the degree of exactingness of this acoustics to the room. Next, we analyze the sound of the speakers using the list of characteristics and terminology described above. We try to avoid subjective comments and at every opportunity we make a footnote to the measurement result, which confirmed one or another feature of the sound. In general, the entire analysis of the sound is done in the key of linking with the measurements. Be sure to pay attention to the following parameters:
The nature of the work of acoustics in each of the key frequency ranges, how much one or another range is accentuated;
The nature and quality of the stereo effect (the width of the stage, the positioning of sound sources and instruments on it), for acoustics 5.1, an assessment of the spatial positioning is given separately. Do not forget to place the acoustics correctly (the angle to the front pair is 45 degrees, the distance is slightly more than the stereo base, the rear pair is twice as close to the listener as the front one, all the speakers are at ear level);
Detail, sound transparency, "graininess" (post-pulse activity at medium and high frequencies);
The presence of color and its character in different ranges, timbre balance and naturalness of sound;
The clarity of the sound attack (impulse response) and separately - the operation of the subwoofer (if any);
Saturation of the signal with harmonics (warmth or coldness of sound);
Micro- and macrodynamics of sound, detail of background sounds, "openness" or "tightness" of sound (dynamic range width, transient response quality GG);
Optimal tone settings.
Here, a general assessment of acoustics is given, first of all, the correspondence of the solutions used in it to the final result and price category. It is estimated how successful the acoustics are, the perspective is suitable as a "blank" for modifications. A list of the pros and cons of the system is given.
Conclusion
The assiduous reader, having completed reading this article, probably brought out something new and interesting for himself. We did not try to embrace the immensity and cover all possible aspects of the analysis of acoustic systems and, moreover, the theory of sound, we will leave this to specialized publications, each of which has its own view on the line where physics ends and shamanism begins. But now all aspects of testing acoustics by the authors of our portal should be very clear. We never tire of repeating that sound is a subjective matter, and it is impossible to be guided when choosing acoustics by tests alone, but we hope that our reviews will greatly help you. Have a good sound, dear readers!
Permission, requests immediately rained down to make a similar selection but for the traditional CD format - that is, 16 bit / 44100 kHz.
I must admit that I have accumulated a fair amount of this kind of music, but over time I made a certain distillate - the most important and necessary from the point of view of me, as an ordinary consumer of popular music. What I run as soon as I get a new device in my hands.
I must say right away that in most cases it is not even the songs themselves that are important, but from which particular edition they are borrowed. I made notes in brackets indicating the main information about the publication (the tags indicate a little more in detail there). I think everyone understands that Audio-Fidelity, MFSL (Mobile Fidelity Sound Lab) and Telarc are the names of record labels. In other cases, you yourself will easily understand everything, nothing complicated and especially abstruse. Quite a lot of what is presented is taken from the most typical releases, and not limited collector's CDs.
I post the archive in FLAC format. When listening on players with automatic track volume leveling, be sure to turn it off (like Replay Gain), this will greatly interfere with testing!
The tracks go chronologically, from 1965 to 2006.
01 The Beatles- Yesterday (mono, EMI mono box remastered)
02 King Crimson- 21st Century Schizoid Man (Japan, IECP-30001)
03 The Velvet Underground- Candy Says (closet mix, Polydor box, 527 887-2)
04 The Beatles- Old Brown Shoe (remaster, Japan TOCP-71016)
05 John Lennon- Crippled Inside (MFSL)
06 The Doors- L.A. Woman (40th anniversary mix, Japan, WPCR-12721)
07 Yes- Round about (MFSL)
08 P.I. Chaikovsky- The Nutcracker, Op.71 Miniature Overture (Andre Previn, The Ballets box)
09 deep purple- Woman From Tokyo (Audio Fidelity)
10 Pink Floyd- Us and Them (CP35-3017, 1st Japan CD issue)
11 Alice Cooper- Generation Landslide (Audio Fidelity)
12 Dire Straits- Down to the Waterline (Mercury)
13 J.S. Bach- Toccata & Fugue in F, BWV 540 (Michael Murray, Telarc)
14. Zodiac- Zodiac (Gala)
15 Pantera- Walk (ATCO)
16 Gloria Estefan- Con Los Anos Que Me Quedan (Sony)
17 Nirvana- All Apologies (Japan, UICY-75127)
18 Massive attack- Teardrop (Virgin)
19 Steve Turre- Puente of Soul (Telarc)
20 Beck- Paper Tiger (MFSL)
21 Bill Frisell- Boubacar (Nonesuch)
Now (as briefly as possible) I will explain what to listen to and what to focus on.
"Yesterday" in a mono remaster, it demonstrates a fantastic effect of presence and (surprise!) voluminous space. If you do not hear anything, then there is a weak link in the audio system.
"Old Brown Shoe"- a very capricious track, it does not open up on all systems (even on high-quality ones it does not always work as it should), but if you are lucky, you will hear an amazingly lively sounding ensemble - each instrument is very clearly, readable and harmoniously spelled out, with a sharp solo guitar and the most resilient bass.
"Crippled Inside"- a very interesting sample on which I check the rhythm of the system. This track should literally dance in a very complex and well-coordinated rhythm. On cheap, cloudy, or overly fat systems, this rhythm disappears.
"Candy Says"- a specific sample, I consider it as an example of the fact that lo-fi music, recorded fuck knows where and fuck knows how, can actually sound extremely lively and naturalistic, largely because there is nothing superfluous and you can feel every sound. By the way, this often happens on the recordings of artists who are considered to be lo-fi.
"21st Century Schizoid Man", "Generation Landslide", "Woman From Tokyo"- nothing supernatural, just exemplary transfers of old analog heavy music.
"L.A. Woman"- Checking the system for scale. At high volume and on large speakers (or adequate headphones), the space becomes almost limitless. True, it does not always work and not on all systems - even very first-class devices sometimes misunderstand this entry. This test is for rock-oriented technique!
"Round about"- Filigree recording for the analog era, made so wonderfully that it should play on almost anything, in detail, rhythmically and with a pleasantly even tonal balance. In principle, this is the track that I usually launch first, because if it does not play, then why the hell did such a technique give up?
From the classics, two tracks - an analog recording of Tchaikovsky from 1972. I am sure that if you wish, you can find better quality ( "Nutcracker" recorded millions of times), but after long selections, I settled on this track. He plays gently and at the same time very energetically. At the fortieth second, it must ring wonderfully. They write that the recently released new box with the same recordings by Andre Previn sounds even better, but I'm reluctant to buy it a second time, to be honest.
Second track - "Toccata & Fugue in F" by acclaimed organist Michael Murray. Why Bach's organ works are needed for the test, I think, there is no need to explain. Interestingly, this is a 1979 recording, but digital! That is, this is one of the very first digital audiophile recordings available to people.
"Down to the Waterline"- an excellent product from audio perfectionist Mark Knopfler, it is especially interesting to listen to the first minute of the track. To be honest, I would even more enthusiastically recommend "Telegraph Road" from another Dire Straits album, but that one is too long, I tried to make the playlist not too long.
"Us and Them"- a completely different case. "The Other Side of the Moon" is a difficult record, and from an audiophile point of view, it falls short of "Wish You Were Here", "Animals" and even "Meddle". But since in any case almost every audiophile dreams of listening to this album with maximum comfort and pleasure, there is a first press CD "The Dark Side of the Moon" for him. There is a big problem - it was released with pre-emphasis correction, but I converted the recording into a form that is playable on computers and audio players. The record will play very quietly, but there will be explosive moments, and they should not descend into chaos - a tough task for many systems.
"Con los anos que me quedan" And "Lay Baby Lay"- folk and blues samples for testing female vocals of very different timbres.
By using "Walk" you can make sure that your system correctly perceives modern metal forms.
"All Apologies" in turn does the same job for the alternative music sound, there is an impeccable recording and mix with a fully immersive effect and very noticeable vibrations even from the quietest sounds.
"Puente of Soul"- typical for Telarc masterfully recorded energetic jazz.
"Boubacar"- atmospheric folk jazz fusion is beautiful in every musical layer (and there are many of them).
"Teardrop"- the only electronic track in the compilation. Yes, in general it will be enough - it has everything you need, and by and large it should sound perfect on any system with pumped bass.
Still there is, however, the track of the electrogroup "Zodiac"- a demonstration of the fact that Soviet sound engineers were not born out of thin air. Although formally it is an electronic instrumental group, the instruments there are lively and sound extremely natural and natural, with very warm harmonics.
And finally we come to Paper Tiger, which is taken from the most, probably, ideally directed (but capricious!) alternative rock album - Beck "Sea Change", and it is the release from MFSL that is of particular value (I came across some other, much more terrible transfers). On a number of audio systems, this song has difficulties, primarily with sticky vocals and loss of rhythm. This should not be. Just as there should not be any kind of rigidity - ideally, everything flows velvety and soft.
P.S. Claims "why there is no such and such a track" are not accepted - believe me, I could make the playlist ten times longer. But if you have any complaints about the sound of some samples, I'm ready to discuss.
And just lovers of good music. I present to you a well-chosen high-resolution albums, namely "Test discs for checking and listening on high-quality equipment", these discs are the result of my carefully selected collection over several years, although I sometimes just listen to them, I advise EVERYONE to download, listen and enjoy the great the sound of these discs:
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12. HDCD Sampler Volume 2 downloadbelow368.58 MB FREE!!!
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14. MARANTZ KI Pearl Lite - Inspired By Desire downloadbelow668.18 MB FREE!!!
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By the way, test disks for audio tuning will be replenished right here, so check back periodically ...
Please leave comments below so I can get back to you. Don't be afraid to join me
Let's imagine a person who is interested in music, but has never paid attention to sound quality. And so, having heard a lot about Hi-Fi and High-End technology, he decides to personally check what “real sound” is. As a rule, he does not have much money, and it is a pity to spend it, it is still unknown what. This is exactly the kind of person our bookshelf speaker test will be very useful for, and just in this price range you can find speakers that can demonstrate true Hi-Fi sound quality. Yes, you will have to make a small allowance for the depth of the bass. But, on the other hand, bookshelf acoustics, as a rule, play better at low volumes than floorstanders, and it will be easier to place it in the room. A dozen speakers is a rich choice. I am sure that among them there are very, very worthy specimens.
Criteria for evaluation
We are dealing with classic "workhorses", and the approach to testing is quite traditional. Frequency response and SOI will show us how flawlessly the speaker design is made from a technical point of view. Together with design features model, this will constitute a design estimate.
Listening will make its own adjustments and will reveal the nature of the sound of the speakers. Good bass depth and at the same time its high quality are rarely combined in shelf speaker format, so we will not be too strict about this parameter. But the presence of a clean and even upper register is quite within the power of small speakers. The importance of this parameter is extremely important for a natural, natural presentation of musical material. High-quality sound at low volume is also important and is an indicator of smooth, almost linear speaker dynamics. Timbre fidelity will allow you to enjoy the full beauty of the sound of each individual instrument. After all, musical instruments are created in order to enjoy their sound, and not to try to understand what exactly is playing. All this adds up to a sound score. The last estimate is inversely proportional to the price: the higher the price, the lower the estimate.
Acoustic Energy 301
Sound: 4Construction: 4
Price: 4
Advantages:
- High detail
- Timbre fidelity
Flaws:
- not enough air
When developing the 300 series, the designers sought visual minimalism. All small details such as screws, grill mounts are excluded from the appearance. The front wall of the speaker is finished with a black rubber-like coating that blends in color with the cones of the emitters. The finish of the speakers is also minimalist - black or white lacquer. The 301 features a signature 28mm fabric dome tweeter and a traditional, well recognizable 110mm bent, heavily anodized aluminum cone mid/bass driver. This speaker is a distant legacy of the legendary AE1 monitors.
Bookshelf acoustics Acoustic Energy 301 Curiously, the company decided to use a slotted bass-reflex port placed on the front panel. It was possible to save the size of the column with the convenience of its placement near the wall.
Sound
The absence of any noticeable color of the sound allows the speaker to turn around and, even playing rather restrainedly, present musical compositions in an interesting way. The smallest details are clearly distinguishable, and the timbres are very close to natural. The entire frequency scale is well balanced both in terms of level and dynamics - the sound is holistic.
Upper-register intelligibility is not bad, but it is a bit lacking for an open sound with enough air. On complex compositions, the intelligibility of musical material is reduced. At low volume, the character of the sound almost does not change.
measurements
The frequency response is very flat. The decline in the low-frequency region is uniform. Bass of medium depth. THD is quite low up to the lowest limit and practically does not depend on the volume level. The impedance is unstable.
Bowers & Wilkins 685
Sound: 4
Construction: 5
Price: 5
Advantages:
- Spacious sound
- Fast bass
Flaws:
- Slight simplification of timbres
The model represents the junior line of Bowers & Wilkins. With a laconic modern design, the line nevertheless inherited some technologies from the flagships themselves. Of course, this only applies to inexpensive and efficient solutions, such as Nautilus tubes for the tweeter, Kevlar cones and a bass reflex port with a golf ball surface. The aluminum dome tweeter is surrounded by a special material to help achieve surround sound. The midrange/woofer uses a static bullet to smooth out the high frequency response.
Bookshelf speaker Bowers & Wilkins 685 The crossover of the model is minimized as much as possible - it is of the first order. The speaker cabinet is finished with a film, and the front panel is covered with a velvety material that is pleasant to the touch.
Sound
The sound of the model is open, light. Detail is at a good level. Bass is tight and fast. Localization is clear. Impressive dynamic range.
Instrument timbres are slightly simplified at mid frequencies. At the same time, the upper case area is very active.
It adds airiness and spaciousness to the sound. Models are characterized by increased emotionality, expressiveness.
measurements
Irregularities are noticeable in the region of 2.5 kHz and 6-7 kHz, which disappear when the column is rotated by 30 °. However, the frequency balance is slightly shifted to the low-frequency region. THD is extremely low. The impedance is extremely unstable.
Canton Chrono 503.2
Sound: 4
Construction: 5
Price: 5
Advantages:
- Clean uppercase
- Accurate reproduction of timbres
Flaws:
- Bass is weak at low volume
Chrono 503.2 is a real German column: excellent workmanship, 100% quality control of each piece, Made in Germany. Despite the declared glossy finish, the column is pasted over with a film, and only the front panel is made glossy. The size of the column is not very large, but the speaker managed to accommodate an impressive 180 mm. Of course, it is equipped with the traditional Canton aluminum diffuser. The suspension is made in the form of a wave for the most linear and long piston stroke of the diffuser. The dome of the 25mm tweeter is made from a very light but strong aluminum-magnesium alloy. For reliability, it is protected by a metal grill. There are two threaded holes on the bottom for mounting on a rack or bracket.
Bookshelf speaker Canton Chrono 503.2 
Sound
The musical material is presented very carefully. The frequency balance is almost perfect. Instrument timbres are transmitted with high fidelity, and small details are not lost sight of. Increased emotionality is not observed, but thanks to a wide and even dynamic range, the speakers manage to accurately convey the musical idea of the composition. The bass is collected, neat, exactly in its place. However, it is not very deep, and at low volume it loses ground even more. At first it seems that there are too many high frequencies, but they appear exactly when you really need them, and in the right amount. The upper register is very clear, which will certainly be appreciated by fans of modern electronic music.
measurements
The frequency response is flat, although it depends quite strongly on the listening angle - the directivity of the speakers is relatively narrow. The THD is very low, and there is a good margin at low frequencies. The impedance is unstable.
Chario Syntar 516
Sound: 3
Construction: 4
Price: 4
Advantages:
- Emotional presentation
- Clear localization
Flaws:
- Tone simplification
The Italian column is made in the most classic design with veneer finish. HDF boards are trimmed on both sides with natural wood before sawing the walls of the body. This makes the column more durable. The assembly and further processing of the case are carried out manually by specialists in Italy. Finished copies are carefully tested for compliance with the required acoustic parameters. The Silversoft Neodium tweeter uses a special aluminum powder-coated membrane, just like the company's top-of-the-range speakers. It is interesting that a significant part of the mid-range is also given to the tweeter - starting from 1 kHz. The shape of the midrange/woofer cone, twice curved, was selected by the designers specifically taking into account psychoacoustics and during months of research.
Bookshelf speakers Chario Syntar 516 The bass reflex port terminates in a simple hole cut asymmetrically into the bottom. High rubber feet on the bottom of the case allow the port to work quite efficiently.
Sound
In the sound of the speakers there is, on the one hand, softness, slowness, and on the other hand, a very clear, active upper register. The timbre picture is slightly blurred, the smallest details are veiled. And meanwhile, the speakers manage to quite accurately, emotionally convey the mood of musical compositions. The bass is quite deep and slightly dominates the overall sound picture. With good localization, the music scene lacks clarity and transparency. This is more noticeable on complex compositions. At low volumes, the bass weakens, but the sound remains quite dynamic and emotional.
measurements
The best frequency response is observed at a listening angle of 30°. The unevenness is relatively good, a smooth decline in the bass. THD is quite good down to the lowest frequencies. The impedance is relatively stable.
Dynaudio DM 2/7
Sound: 5
Construction: 5
Price: 5
Advantages:
- Timbre fidelity
- Clean uppercase
Flaws:
- Severity in serving
The DM line is the entry level of acoustics in terms of the well-known Danish company Dynaudio. The column is designed in a quite recognizable style of this company. The gray front panel is specially made thicker to effectively dampen cabinet resonances. The case itself is also carefully muffled and finished with traditional veneer as well. The branded tweeter is equipped with a 28 mm textile dome impregnated with a special composition. The midrange/woofer cone is molded from the already well proven magnesium silicate polymer. The voice coils of the drivers are wound on a kapton base with light aluminum wire. Together with powerful magnet systems, this allows for remarkable dynamics and sensitivity.
Shelf speaker Dynaudio DM 2/7 Special attention given the maximum linearity of the impedance to minimize the dependence of the speakers on the amplifier.
Sound
The presentation of musical material by the column is liberated, natural. Excellent timbre resolution makes the sound stage very believable. The spatial arrangement of tools is clearly visible.
The bass is tight and well defined. The upper register is clean and pleasant to the ear. The sound is highly detailed and lacks coloration. The speakers play just as confidently at low volumes as they do at high volumes.
measurements
The frequency response is extended into a very even strip with a barely noticeable skew to high frequencies. The focus is broad. THD is low and stable. The impedance is fairly stable. exemplary results.
Magnat Quantum 753
Sound: 5
Construction: 4
Price: 4
Advantages:
- Timbral accuracy
- Clean music scene
Flaws:
- Slightly sparse sound
A column from the Quantum 750 line of the mid-range price range from Magnat looks solid. The front wall is made thick (40 mm) in order to drastically combat cabinet resonances. A solid podium with a thickness of 30 mm also emphasizes the solidity of the structure. It is curious that the front panel and podium are polished to a shine, while the rest of the body surface is matte. The F-max tweeter is equipped with a double textile compound dome and has an extended operating frequency range. The midrange/woofer cone is made of ceramic/aluminium. The voice coil is well ventilated. The aluminum speaker basket design is optimized for optimal airflow and reduced resonance.
Bookshelf acoustics Magnat Quantum 753 The bass-reflex port with a large horn is placed on the rear wall. The crossover is optimized in terms of phase and amplitude of the signal and is assembled from selected high-quality elements.
Sound
Speakers play emotionally, dynamically, quickly. At the same time, the timbres of the instruments are perfectly transmitted, and the musical stage is not obscured by extraneous overtones - they are pure and deep. Sound source localization is excellent. Detailing is also at a high level.
The treble level is enough for an open sound with the presence of airiness, and at the same time the upper register is very neat, unobtrusive.
The bass is of medium depth, collected and fast. There is a little lack of physicality, density of presentation. At a low volume, the enthusiasm of the speakers is lost, the emotionality fades.
measurements
The unevenness of the frequency response is minimal, but the frequency imbalance towards the HF is obvious. The SOI varies within 1% and significantly depends on the loudness, but there are no obvious resonances. Good margin of SOI at low frequencies. The impedance is unstable.
Martin Logan Motion 15
Sound: 4
Construction: 4
Price: 3
Advantages:
- Energetic feed
- Fast and tight bass
Flaws:
- Weak at low volume
The speakers are eye-catching with their amazing natural finish and attractive black steel grille. The case cover is slightly tilted back. There is another surprise under the grill - a ribbon tweeter (a sign of an expensive device). The front panel of the speaker is made of black anodized aluminium. The cone of the long-throw mid/bass speaker is also made of black anodized aluminum to match the panel. The radiators are matched through a crossover with an improved topology, assembled on low-loss polypropylene capacitors and electrolytes, as well as hand-wound inductors.
Bookshelf acoustics Martin Logan Motion 15 The circuit provides thermal and current protection. The phase inverter port is brought to the rear wall. The speaker cabinet is assembled from 19 mm thick MDF boards.
Sound
The peculiarity of the speakers is that they do not like to play at low and medium volume at all. In this mode of operation, only the midrange remains from the frequency range, and the dynamics become inexpressive.
As the volume increases, a fast elastic bass and quite detailed highs appear. However, the lower middle still continues to prevail. The presentation of musical material is biting. At the same time, we must pay tribute, no extraneous overtones are felt, on the contrary, the overtones sometimes disappear even where they should have been.
The model tends to slightly simplify the timbres of the instruments. At the same time, the ribbon tweeter is very well heard, which gives a characteristic delicate color to the mid-high range.
measurements
Noticeable uneven frequency response in the HF region. The decline in sensitivity towards low frequencies is quite sharp. The focus is broad. THD has small rises in the midrange region, but nevertheless remains below 1%. The impedance is relatively stable.
MK Sound LCR 750
Sound: 5
Construction: 5
Price: 4
Advantages:
- Focused sound
- Good timbre resolution
Flaws:
- Do not hide recording flaws
All acoustic systems of the American company M&K Sound are executed in black color without any embellishments. And the main decoration of products - compliance with the highest standards of sound reproduction. The 750 series is a compact set of speakers for creating a home theater. And the most big column in the series (not counting the subwoofer) - model 750 LCR. The column is very unusual, especially in our test. First, the closed acoustic design reduces the bass response. Secondly, the use of two midrange / woofers at once significantly expands the dynamic range of the speaker. Third, the tweeter panel turned 4.7° away from the listener likely increases and/or equalizes the dispersion of various frequencies. The dome of the tweeter is made of silk covered with polymer.
Bookshelf acoustics MK Sound LCR 750 
The diffusers of the speakers are polypropylene, with a mineral filler. Of particular note is the phase-focused (Phase-Focused) crossover, which significantly improves almost all the parameters of the column. On the back wall there are many threaded holes for different options for mounting the speakers.
Sound
Excellent control of musical material. The sound is almost monitor, smooth. All instruments are at a glance: they are clearly defined both in space and in timbre. Nothing superfluous interferes with the overall musical picture, all the nuances are heard clearly. And since there is no emotional coloring, the sound of the speakers is not as exciting as that of many other models, and depends entirely on the musical composition itself.
measurements
The irregularities in the frequency response of the column are insignificant. A 30° turn gives the best results. THD is very low and grows very smoothly towards low frequencies, exceeding 5% only at low volume. The impedance is fairly stable. Very worthy results.
PSB Imagine B
Sound: 5
Construction: 5
Price: 3
Advantages:
- Natural tone reproduction
- Smooth dynamics
Flaws:
- Limited HF area
The Canadian company PSB has been offering the Imagine line for several years. During this time, she managed to earn the Red Dot award for design and a lot of positive feedback from various experts. The column body is a geometric intersection of several elliptical cylinders. All walls are curved. And this creates a feeling of solidity, structural strength. The 25 mm tweeter also looks solid - a dome made of durable titanium, the coil is cooled by magnetic fluid, a powerful neodymium magnet. The midrange/woofer cone is made of polypropylene with clay-ceramic filler (mineral). The phase inverter port is brought out from the back side. The column is qualitatively finished with natural veneer.
Bookshelf acoustics PSB Imagine B 
Sound
The sound is collected and well balanced frequency. Excellent localization and natural reproduction of timbres make the musical scene almost real, alive. Smooth dynamics allows the speakers to play naturally, liberated even at low volumes. The musical matter is pure. The HF range is slightly limited, due to which the airiness is partly lost, turning into an intimacy.
Speakers can miss the smallest details, but at the same time retain expressiveness, richness of sound. The bass, although not deep, is very well designed. Very good and mid frequencies, timbre saturated and quite correct.
measurements
A very flat frequency response measured along the acoustic axis. Turning the speakers away from the listener is undesirable - they begin to pass the HF. SOI is stable and low down to the lower frequency limit. The impedance is stable.
Rega RS1
Sound: 5
Construction: 4
Price: 4
Advantages:
- Clean uppercase
- Wide dynamic range
Flaws:
- Slight sound coloration
The English company Rega has developed and offers customers a single series of RS speakers. The purpose of their creation is to harmoniously complement other sound technology, also developed within the walls of Rega. However, speakers are available to buyers and separately from this technique. Model RS1 is quite compact and, judging by the weight, is assembled from thin MDF. Despite this, the performance of the speakers is up to par, there is a neat veneer finish and a strict design. The emitters are designed by Rega engineers and assembled by hand in-house. The 19mm tweeter features a specially shaped rear chamber for better damping of sound waves from the back of the tweeter dome. Midrange/woofer with paper cone.
Bookshelf speakers Rega RS1 The smooth frequency response of the speaker makes it easy to integrate it with a tweeter using a simple crossover with good phase synchronism. The phase inverter port is brought to the rear wall.
Sound
The speakers convey timbres quite accurately, but due to the slight coloration, the music scene becomes a little less transparent. There is a slight lack of upper case, but it is very clean. Details are present, but slightly veiled. The musical material is presented in a sweeping, open manner.
The bass is quite accurate, but it sometimes lacks weight. The localization of sound sources is somewhat blurry.
Complex music manages the column a little worse - the intelligibility of sound material is reduced. However, at low volume, the speakers play very convincingly.
measurements
Irregularities in the frequency response in the region of the upper middle and treble form a special character of the sound of the speakers. Speakers play more evenly when rotated 30°. THD is unstable, but quite low, less than 1%. The impedance is extremely unstable.
Triangle Color Bookshelf
Sound: 5
Construction: 4
Price: 5
Advantages:
- Open live sound
- Accurate reproduction of timbres
Flaws:
- Slight excess of bass
Very nice-looking speakers from the French manufacturer Triangle are available in three lacquer colors - white, black and red. The Color line stands out with its bright, cheerful style among all Triangle products and takes the place of the entry-level line.
The shelf model uses a titanium diaphragm tweeter and a paper cone mid/bass driver. In general, the speaker is quite interesting, its suspension is wide, corrugated and basically made of cloth. The paper diffuser is coated with a special composition. The dust cap is made in the form of a bullet. The design of the crossover uses developments from the top Magellan line. The bass reflex port is located on the back of the speaker.
Bookshelf speaker Triangle Color Bookshelf 
Sound
The sound of the model is very lively, natural. Timbre fidelity is very high. The presentation of sound material is natural and unconstrained.
Dynamics surprisingly accurately repeats a live performance. The bass is deep and well defined. Sometimes it even seems that it is too much.
The musical matter is very pure and exceptionally detailed. No nuances escape from the field of view of the speakers.
They cope with compositions of any complexity. Sound quality is not lost even at low volume.
measurements
The imbalance of the frequency response towards the HF is obvious. It is treated, as usual, - turn the AC by 30 °. The THD is quite low, although it is significantly higher in the midrange, but remains within 1%. High volume causes slightly more distortion in the upper bass. The impedance is unstable.
Wharfedale Jade 3
Sound: 5
Construction: 5
Price: 4
Advantages:
- Good detail
- Clear localization
Flaws:
- Slightly weakened dynamics
The British company Wharfedale traditionally spares neither effort nor materials, even for budget lines. And the model Jade 3 once again confirms this. In our test, this is the largest and heaviest speaker, and the only 3-way speaker. The curved-walled case is a hallmark of the top lines from many other manufacturers, but not from Wharfedale. Both the shape of the hull and the additional bulkheads make the hull as acoustically inert as possible, preventing unwanted sound coloration. High frequencies are handled by an aluminum dome tweeter. At the border of 3 kHz, it is replaced by a midrange speaker with a cone made of aluminum-cellulose composite. And already in the region of 350 Hz, the initiative is taken by the woofer, equipped with a wicker diffuser made from a mixture of coal and fiberglass. The combination of these materials with a woven structure brings the cone closer to the ideal piston, eliminating the problematic resonance phenomena inherent in metal cones.
Bookshelf speaker Wharfedale Jade 3 The speakers work in a closed volume. The speaker crossover has been computer optimized for maximum phase linearity.
Sound
Wharfedale speakers sound traditionally beautiful. All tools are clearly spaced. The music scene is clean and spacious.
The bass speakers are served neatly, unassertive, as if afraid to damage the balance of the overall sound picture. The same can be said about the upper case.
The softness of the presentation of musical material is combined in an interesting and harmonious way with excellent sound detailing. In addition, the speakers play very well at low volumes.
measurements
The frequency response of the model is flat, but behaves in a peculiar way at HF - a decline and a sharp rise. The bass is deep. SOI is almost perfectly flat and extremely low. Very solid margin for low frequencies. The impedance is pretty stable.
conclusions
It should be noted that it is becoming less and less interesting to study the results of column measurements in our test laboratory. Almost all models showed remarkably flat frequency response and very low SOI even in the bass area! This is explained by the fact that almost all companies have already adopted computer modeling tools, with which you can make everything sound, perhaps, which has been proved to us more than once, for example, by Boston Acoustics. Even the shape of the hull no longer plays such a significant role, the main thing is to correctly calculate the damping elements. Therefore, the ratings for the design of all models are either good or excellent.
Two models from our test deserve special mention. These are MK Sound LCR 750 and Dynaudio DM 2/7. The companies that created them are initially focused on the development of professional acoustics and lead this line even in their youngest lines. The main principle is the maximum accuracy of the transfer of musical material. And no embellishments. These two models fully comply with this principle and, in fact, are professional-level monitor acoustics, with all its advantages and disadvantages. Not all listeners may like it precisely in terms of sound, more precisely, in terms of neutrality of sound. This is a product for special connoisseurs and connoisseurs of music or even for home studios. Both models are worthy of the sympathy prize.
Virtually all companies have adopted computer simulation tools, with which you can make sound, perhaps, anything.
If we talk about beautiful and comfortable sound, then many speakers of our test successfully coped with this task. Accuracy of timbre transmission, accurate localization, accurate bass - all this is inherent in almost all tested speakers. The difference is only in the nature of the sound. And here the choice turned out to be rich: in the test you can find both a dense, rich sound (PSB Imagine B), and an imposingly refined sound (Wharfedale Jade 3), and a neat presentation of the material (Canton Chrono 503.2), and an open airy image (Rega RS1, B&W 685), and even defiantly aggressive pressure (Martin Logan Motion 15). However, most of all I would like to highlight the French speakers Triangle Color Bookshelf. They turn practically any musical material into a celebration of sound. Speakers are able not to miss the main idea of the work and at the same time present the material very beautifully, lively and dynamically. They are very pleasant and interesting to listen to. The Triangle Color Bookshelf wins the test.
Test audio tracks (tracks)
for checking and adjusting household and car acoustics, audio equipment
Description, instructions for using test audio CDs "AudioDoctor FSQ" and "AudioDoctor FSQ 2"
Quite often one hears the opinion that " HERE IS MY AUDIO SYSTEM PLAYING GREAT", however, during test listening, something often comes to the surface that is rather difficult to describe in words.
And it happens that the owner of the complex gets hung up on the fact that his equipment works "SOMEWHERE WRONG" and alterations, adjustments and many different, sometimes unnecessary, movements begin.
For the first time, I encountered test signals after purchasing the SURF E-024S equalizer, which had a built-in generator for fourteen fixed frequencies. That's when I realized that in addition to the sound, the overtone is of no small importance. When checking with a test signal of 31 Hz, it turned out that it was at this frequency that window glass began to resonate, and at a frequency of 63 Hz, plates folded under the bed began to tinkle.
The conclusion suggested itself - test signals or fragments of an audio recording are necessary not only for setting up and testing ultra-high-quality audio equipment and acoustics, but it is far from superfluous to check the audio path and the household complex.
In 2005, the magazine "AVTOZVUK" released an audio CD with test audio fragments and a description of how to use this CD when setting up the acoustics and the complex as a whole. Although the disc is already quite old, it has not lost its relevance to this day. Your attention is invited to the recommendations from this verification disc from the manufacturer and online verification of your computer audio system, as well as a copy of the disc recoded into WAV format, with virtually no loss in quality from the original CDA format.
To fully test the audio system with test signals, you will need the text attached to the disc:
PART I. TECHNICAL TRACKS
Turn on and warm up your audio equipment, put in a disc, arm yourself with a remote control and sit comfortably in your usual place. If you want to increase the accuracy (and hence the reliability) of measurements, try to get a sound level meter, it will greatly simplify the work.
So, to begin with, let's check the margin for the undistorted volume level, this is one of the most important indicators.
In a well-tuned sound path, even with the volume control fully engaged, no wheezing and other distortions should be heard from the speakers. However, the maximum undistorted volume level for equipment of different classes is different - one can bring down the ceiling, the other can only block a loud conversation.
What is the optimum for home conditions?
For reference:
A loud but calm conversation of two or three interlocutors standing next to each other usually reaches 75 - 80 dB.
The average volume level in the stalls of an auditorium of medium and large capacity from a jazz quartet does not exceed 80 - 85 dB, a symphony orchestra (not higher than Forte) 85 - 90 dB, and at a rock concert it can reach a pain threshold of 120 dB. Learn more about volume and audio sources.
Theoretically, 120 dB can be achieved at home, since modern technology this allows. But let's look at things realistically: if you live in an ordinary panel house, where walls and ceilings rarely have sound insulation of more than 40 - 45 dB, then even quite peaceful neighbors will be forced to call the police.
Therefore, it is generally accepted that the average volume level when listening to music in an apartment is 85 dB. And if your equipment can develop an undistorted volume 10 dB more, i.e. 95 dB., then this is quite enough. If this is not enough for you, you will have to fork out not only for more powerful equipment, but also for additional soundproofing of the room.
If the room requires additional sound insulation of 10 - 12 dB, then it will be provided by a carpet with a thickness of at least 1.5 cm over the entire floor area (if parquet or parquet boards on a bitumen basis are available) plus pasting at least 75% of the walls with additional absorbent materials (Daekwell , Cotex and similar). In addition, it will be necessary to lay the entire ceiling area with gypsum boards with a thickness of at least 1 cm.
The undistorted volume level is determined by the first track of the test disc. A musical fragment sounds on it, where the vocal and bass parts are additionally compressed. Gradually increase the volume level from zero until the overload begins, when non-linear distortions, perceived audibly as wheezing, begin to be clearly heard on the bass and vocals. This is the limit of the sound path in terms of undistorted loudness. Remember this position of the regulator.
To accurately determine the value, you need to use a sound level meter. Very convenient here is a small-sized digital instrument (FWE 33-2055 or similar in function and overall dimensions) with a weighing filter "C". The measurement procedure is simple: the sound level meter is mounted on a tripod in the place where you usually sit when listening. Without changing the volume control position, play track #15 with the pink noise signal. The device will show the exact value of the undistorted volume level, by which you can judge whether you will interfere with your neighbors.
The next step is to set the standard volume level. All of the following tracks on the test disc should be heard at the same volume level. If you are used to listening to music at a very specific position of the volume control - put it on this mark. If you prefer the 85 dB level mentioned above, use the sound level meter again. Turning on track No. 15, set the amplifier control to 85 dB on the scale of the device (do not forget to turn on the “C” weighting filter).
If you do not have a sound level meter, invite two or three friends and ask them, without forcing their voices, to discuss some problem. Focusing on the volume of the conversation and periodically playing track No. 1, try to set the same volume with the amplifier control. The accuracy of this operation depends on your patience.
Remember the position of the volume control and do not change it until the end of listening to the test disc!
On test tracks No. 2 - 4 the phasing of the audio path between the channels is checked.
For reference:
With correct phasing on a monophonic signal, the cones of the left and right channels move synchronously (forward and backward). In this case, the sound image reproduced by the stereo system will be perceived exactly from the middle between the right and left speakers. If the phasing is broken and one diffuser lags behind or ahead of the other, then the sound image in the center blurs, becomes fuzzy, or even shifts to one side.
On a stereo soundtrack, incorrect phasing leads to a distortion of the sound perspective. For example, some of the musicians in a symphony orchestra may end up in completely different places. Or a rock vocalist soloing in the center of the soundstage suddenly appears in the corner or even in the back of the stage.
On the "AudioDoctor FSQ" disk, phasing is determined separately for medium, low and high frequencies. On track No. 2, the voice of the announcer is recorded with the words: “Mid frequencies. Phase". These words should be heard from the center of the sound stage. Then the announcer says: “Mid frequencies. Antiphase". In this case, the narration should be played at a lower volume level and (or) out of focus for the listener and (or) shifted to one side or another from the center. If the speaker's voice on the last words sounds louder and more focused in the center, then in the mid-range the audio system is acoustically out of phase.
Similarly, the phasing is checked in the HF band along track No. 3 and in the LF band - along No. 4. For greater simplicity, or if the home audio complex is single-band, the phasing check is carried out immediately in the entire frequency band on the pink noise signal recorded on track # 16. The phase signal must be located exactly in the middle of the soundstage.
TREATMENT. If you find that the audio path is out of phase in the entire band, reverse the polarity of the speaker wires on one of the speakers. If the antiphase was found only in one of the bands, the situation is worse. Then pick up a soldering iron or take the speaker (usually this is an acoustic defect) to the workshop.
The presence of interference, rattling, extraneous overtones and noise in the sound path and the listening room is checked by test audio fragments #5 and #6. It is clear that any of the above does not decorate the sound, superimposed on it in the most inappropriate places. We had to listen to the “duet” of the vocalist with the poorly screwed amplifier cover periodically “singing along” to him. Her contribution to the sound was insignificant, so the owner of the system attributed the change in the well-known voice of the performer to the account of poor-quality recording and almost threw the CD away. On a real musical signal, especially a polyphonic one, when many instruments sound simultaneously, it is difficult to accurately track the interfering sounds.
Therefore, for testing on a test disk, a tonal (sinusoidal) signal is used, the frequency of which smoothly changes from the lowest to the highest frequencies (colloquially “sweep tone”). Separately, first for the left and then for the right channels. And here sometimes such “dirt” comes up that you are amazed. Here and the rattling of loose glass in a window, bookshelf or sideboard, and much more.
TREATMENT
1. The method of dealing with rattling is understandable and does not require special consideration.
2. If overtones of heads in the speakers come up on the sweep tone or, which is really bad, self-excitation of the amplifier, it smells like a visit to the repair shop. Diagnosis of self-excitation - spontaneously appearing in the sound "snap" in the high frequencies, noise, which can be especially well heard in the pauses between tracks on the disc.
3. Sometimes at higher frequencies (above 8 - 10 kHz) a series of low-pitched, increasing in frequency squeaks are heard. This is not self-excitation of the amplifier, but the effect of the appearance of a standing wave in the system: the output stage of the amplifier - cables - acoustic load. The sound signal returns from the acoustics to the output stage of the amplifier, adds up to a slightly higher frequency sweep tone, from where the beats arise. On a real sound signal, such a selection of components makes the sound at high frequencies frankly dirty. The fight against this phenomenon is quite simple - change the length or brand of speaker cable. Sometimes bad contact in the terminal connections is “involved” in the case.
4. The most unpleasant symptom is a low-frequency buzz at the very beginning of the sweep tone. In the worst case, it can become so loud that it will block your ears. Here, it is necessary to “treat” not only the equipment, but also the premises. We will learn about what exactly needs to be done from the next track (No. 7), designed to evaluate the low-frequency link of the audio path. Two parameters are determined - the lowest frequency of the operating range and the uneven frequency response up to 150 Hz. The evaluation mechanism here is based on one feature of human hearing - good memory and preference for the perception of low-frequency sounds.
And this is psychoacoustics.
For reference:
Try it at your leisure (if you have two generators audio frequencies) conduct an experiment: apply a signal with a frequency of 5 - 7 kHz to the amplifier. After that, from the second generator with the same level - one frequency, approximately 50 - 80 Hz. You will be surprised: the low-frequency tone will be well audible, and the midrange will either disappear completely or be barely noticeable.
This is called the masking effect, proving our ear's preference for bass. The phonogram, first for the left and then for the right channels, contains a recording of a number of fixed audio frequencies in the low-frequency range. First, the announcer will announce that the frequency is 60 Hz. Let's call it "base". Focus and remember its volume level. Then the announcer will announce 20Hz, 25Hz, 30Hz and so on. In the vast majority of cases, the frequency of 20 and even 25 Hz will be quieter than the reference, and then the volume will begin to increase. The first pure low-frequency tone (without distortion and turbulent sips), which matches in volume with the reference one, determines the lowest operating frequency of the audio path. Memorize it and keep listening. Ideally, the volume of the remaining tones up to 150 Hz should be the same, but in practice dips and bursts of levels are clearly audible. This is the unevenness of the low-frequency link of your system.
Judging by the reviews of users of the test disk, this phonogram is so effective that some fans even use it to adjust the phase inverters in speakers. We would like to note that here our ear surpasses even very cool spectrum analyzers in terms of accuracy of perception.
But back to the possible low-frequency hum that we mentioned above. If it makes your ears pop, highlight on track #7 the frequency at which the maximum rumble is observed. It is from her that you will have to “treat” your room. This, as already mentioned, is the result of the interaction of acoustic systems and the room, a standing low-frequency wave. Acoustics call them modes. In any room there are at least three of them (length, width and depth). But if they are close to each other in frequency, which happens with multiple room sizes (1:1, 1:2), then it is extremely difficult to deal with them.
TREATMENT in such cases it is not easy. Most often, processing is performed in the entire audio frequency band (it's easier) with the help of sound-absorbing coatings - floor and wall rugs, upholstered furniture. This is usually done taking into account the overall design of the room. You just need to remember that synthetic rugs in winter, with dry air in the apartment, can accumulate a significant static charge that can disable displays on equipment. The way out is portable air humidifiers. Good results are also obtained when laying the ceiling, and sometimes the walls, with dry gypsum plaster slabs (SGSH). If it is possible to change the geometry of the room, it can be very effective to lay an additional wall (0.5 bricks) near one of the walls, moving away from the existing plane by 3-5 degrees.
Very effective, although also quite expensive, is the use of stretch ("French") ceilings made of dense fabric. The sloping false ceiling in the form of a monolithic sound-absorbing structure also significantly reduces modal resonances. But if the mode frequencies are known exactly (using track No. 7), then it is best to place sound-absorbing sheets near the ceiling and on the walls, the geometric dimensions of which are a multiple of the mode wavelength. For example, to eliminate the 63 Hz mode, two sheets of perforated plywood measuring 1.25 x 1.25 (1/4 wavelength), suspended from frames near the ceiling, reduce the resonance by 8 - 10 dB.
The unevenness of the frequency response in the region of medium sound frequencies is most noticeable for our ear, especially sharp bursts and dips following one after another (the pros call them “fences”). To evaluate this parameter by ear, without a spectrum analyzer, track number 8 is used. The phonogram on it is a high-quality stereo recording of the applause of a large number of spectators in the hall. Clapping your hands in a rather noisy room is equivalent to a diffuse field - noise, evenly distributed over the spectrum.
However, against the background of this monotonous noise, the human ear manages to distinguish the very beginning of the pops (bursts). On a linear frequency response path, you really hear applause, but when uneven ("fence"), they become like the sound of heavy rain. And the greater the unevenness, the more natural the downpour seems, and the individual pops that stand out from the general sound background, in this case are perceived as annoying drops, strongly knocking on the windowsill.
TREATMENT
The main source of "rain" is acoustics. Manufacturers usually draw eye-pleasing horizontal frequency response lines on packaging boxes, but the reality, especially for speakers with woofers on polypropylene cones, is simply terrifying.
In addition, multiband speakers are distinguished by “raininess”, and most often the maximum unevenness appears at the junctions between adjacent frequency bands, especially with not very high-quality crossovers. Here, there is an incorrect choice of the crossover frequencies, and the joint radiation of the heads spaced apart from each other at the cutoff frequencies (due to the insufficient cutoff steepness of the filters). The magnetization of the cores of the inductors also makes a significant contribution.
The treatment method is the most radical - it is better to get rid of such columns.
On track No. 9, the linearity of the stereo image is determined along the width of the sound stage. This is also necessary in order to check the correct placement of the columns. The phonogram contains seven drum beats, smoothly moving from left to right across the entire width of the stereo image. The impacts are precisely localized in direction, and their movement in space is linear, i.e., the angles between the impacts are the same. The first beat is heard on the first sound plane from the leftmost edge of the soundstage; the second is a little closer to the middle and a little deeper; the third blow is carried a little further into the depth of the sound stage and closer to its middle. The fourth beat should be perceived by the listener exactly from the middle of the sound stage, in depth, on the second - third sound plane. The fifth and sixth beats are similar to the third and second, respectively, but on the right side of the middle of the stage. The seventh strike is in the foreground on the very right side of the scene.
TREATMENT
1. The first hit merges with the second, and the sixth with the seventh - push the speakers apart, they are too close.
2. No depth movement is felt - move the speakers forward.
3. Impact angles are not symmetrical - pay attention to the furniture located next to the speakers or its different sound-absorbing properties. A soft sofa on one side and a polished wardrobe on the other are a sure provocation of such an ailment.
4. If the blows themselves are not very clear in orientation in space (not focused), then there may be two reasons:
- Insufficient resolution of the audio path, most often due to the low quality of the source. This is where the difference between expensive and cheap CD players is especially clearly visible. Equally important here are the parameters of the amplifier, in particular, its phase-frequency response. Cables also have a very noticeable effect on musical resolution, and even more interconnected. Very often, the mixed up direction of the cable makes the sound faded and smeared. You may not believe it, but when you hear the effect live, you will understand that you were wrong. Unless, of course, the class of the audio path allows you to hear the difference. And by no means the last role is played by the speakers, and to a greater extent their design.
- Acoustic processing of the listening room (do not confuse it with soundproofing, which we talked about above). In an insufficiently muffled, booming room, there is always a lot of re-reflections at mid-bass and mid-bass frequencies, blurring the localization of the sound stage, although the sound itself usually has a pleasantly bright, juicy character. At the same time, a muffled room is always better in terms of localization, but the sound loses its cheerfulness and becomes dry. It is clear that in such a case a reasonable compromise is needed, which path No. 9 will help achieve.
Specific example: Listen to the moving drum in a room with lacquered parquet and then again with a carpet covering 40-50% of the floor area. Localization will improve markedly. And then unfold the carpet and cover 100% of the floor area. Localization will be a little better, but the sound will be drier. The same experiments can be done with wall and ceiling coverings, using the acoustic materials and draperies mentioned above. But do not get carried away with sound absorption and do not forget about sound scattering. It should be both, in a compromise. In good studios, there is always a large set of sound absorbers in the form of suspended curvilinear or asymmetrical structures that improve the diffuseness of the sound field.
Note: Track #9 also shows crosstalk between channels. As you know, the snare drum has tensioned springs from below, which are well audible. If, when the drum is moved to the right channel, the after-sound of the springs is heard in the left channel even after the fifth or sixth beat, the sound path cannot be considered high-quality. Most often, the amplifier or source is to blame for this, but sometimes the situation can be improved by replacing the interconnect cables.
PART II. MUSICAL MATERIAL
In this part, you should be especially careful, since for each of the phonograms you will need to evaluate at least two or three parameters. Study the description of the tracks in advance, then the path diagnostics will be noticeably easier.
And the methods of treatment will depend on the specific type of your components, financial capabilities and personal musical preferences.
Track No. 10 determines the microdynamics and depth of the created sound stage. The phonogram is a small piece of music with two instruments - a double bass and a drum set. The recording is of exceptionally high quality. It was produced in a large music studio using two condenser microphones X-Y pattern, 24bit/96kHz. analog signal was digitized immediately after the microphones and transmitted to the console already in digital form.
The drummer and his drum kit are located in the middle of a not very wide sound stage, in its very depths (on the third or fourth sound plane). The double bass player is also far away, slightly to the left of the drum set. At the beginning of the fragment, both musicians play very quietly. Nevertheless, their instruments are well audible, the music is perceived clearly, with exceptionally high detail. The sound of the double bass is bright and full-bodied. Even at such a low volume level, the movement of the musician's bow along the strings and the light tapping of his fingers on the fretboard are clearly audible. When playing pizzicato, the double bass sounds clear and distinct, without interfering boom and blur. The drum beats are full-bodied and resilient. The drummer's "run" over them literally amazes with its clarity and clarity. The cymbals sound very authentic, both when the musician plays very quietly at the very beginning of the fragment, and at the end, when he plays loudly.
Sound evaluation
1. An unacceptable depth of sound stage is considered if the musicians are visually located on a horizontal line between the speakers (that is, in the foreground).
2. With unsatisfactory microdynamics at the very beginning of the phonogram, quiet beats on drums and cymbals are not audible at all, and playing with a bow on the double bass is hardly distinguishable. Microdynamics can be considered satisfactory if the drums, cymbals and double bass are audible, but in the sound of the double bass you can’t hear the musician’s fingers tapping on the fretboard and (or) when the double bass player plays with the bow, you clearly don’t hear the “resting” movement of the bow along the strings. And the microdynamics will be good if the double bassist's fingers are heard clearly and clearly. The sound path has excellent microdynamics and exceptionally high quality if a very quiet rustle is heard (time 1’09”), when the drummer accidentally touches the cymbal with his elbow and immediately clamps it with his hand. You can be proud of such a sound path.
On track No. 11 of the test disc, the naturalness in the sound transmission of the musical attack is determined, as well as the position and focus of the sound stage in width (in the horizontal plane) and height (in the vertical plane).
The phonogram shows a fragment of a drum solo. A clearly expressed localization of the cymbals in direction and depth allows the listener to correctly and accurately assess the spatial arrangement of all the "components" of the drum set. It was recorded in a "close-up", i.e. positioned close to the listener across the full width of the sound stage. The sound is bright, full-bodied and beautiful. At the very beginning of the phonogram, attention should be focused on the playing of the musician. The drums sound bright, with emphasized elasticity and "meatiness", very dynamic and attractive to the ear. The second part of the soundtrack is accentuated on cymbals and hi-hat, articulatory clarity of their sound and position accuracy in stereo space. The hi-hat is located slightly to the right of the middle of the stage, slightly above the snare drum. When the "interruption" on the cymbals begins, the "second" cymbal is visually perceived by the listener to the right, higher and slightly closer to the hi-hat, the "third" - a little to the left.
Further, the musician's playing shifts to the left, and the next, "fourth" cymbal sounds much more to the left and is already noticeably higher than the hi-hat. Then a blow is heard on another cymbal, which is heard even more to the left, higher and closer to the listener. Behind it, the “sixth” is heard, perceived a little higher and deeper than the previous one, and to top it off, the seventh and eighth beats sound almost simultaneously, moved even further away from the listener in depth and located slightly lower than the previous ones. The naturalness of the musical attack is evaluated by the first part of the phonogram, the focusing of the cymbals in space - by the second.
Sound evaluation
1. An unacceptable transmission of an attack is considered if the sound of the drums is dull, there is no elasticity and “meatiness” in it; unacceptable - if the sound of the drums is quite dynamic, but has an element of "cardboardness" in the beat.
Treatment: if the midbass and bass lack elasticity and clarity, place the speakers with spikes on marble slabs 3 - 5 cm thick. In nine cases out of ten, the sound will improve.
2. It is considered unacceptable or hardly acceptable if the sound stage is narrower than the space between the speakers (the extreme right and left plates are shifted to the center), and also clearly below or above the line of the listener's eyes.
3. Unacceptable or hardly acceptable if the cymbals and hi-hat are at the same height (in the vertical plane) or the difference is insignificant (last hits on the left cymbals are only slightly above the hi-hat position).
On track No. 12, the timbre and musical balances of the sound are evaluated. The phonogram is a fragment of a jazz piece with male vocals; the quality of the recording can serve as an example of musically balanced sound. Saxophone, piano, electric guitar, bass guitar and drum set are located across the entire width of the sound stage, on the first and second sound planes, as if arranged in a line next to the listener. The instruments are spatially clearly oriented in front of the listener, musically balanced among themselves and perceived with the same volume.
On the left is the piano, on the right is the guitar and bass. In the middle of the soundstage, just behind the main instruments, is the drum kit. It is recorded widely, drums, cymbals and hi-hats are sort of placed on the front plane. In the center, in front of the drum set, a saxophone is heard a little closer to the listener. The musician during the game sometimes migrates from the middle a little bit to the right, and the movement of the saxophone is felt on the recording. Male vocals are heard exactly from the center of the stereo image. At the very beginning of the play, the singer approaches the microphone from the back of the stage - his voice moves from the background to the foreground and “remains” there until the end of the play. Timbre vocals sound soft and full-bodied, with a good content of low components.
It is clear, crisp and legible, but by no means harsh. The piano is perceived as full, dynamic, with a bright attack and is accentuated in several places in terms of level. The bass is dense, thick, very pleasant in terms of timbre coloration. In the overall sound picture, he is between the first and second plans and does not come forward. The guitar, whose main role in this piece is an accompaniment, is also visually located between the first and second sound planes.
Timbre balance (natural sounding of instruments) and musical balance (balance between the instruments and the vocalist in terms of level) are evaluated by the listener separately.
Sound evaluation
1. It is considered unacceptable or hardly acceptable from the point of view of timbre balance if any of the instruments sounds unnatural and (or) if the vocal timbre has a sharp or unpleasant sound character.
2. It is considered unacceptable or hardly acceptable from the point of view of musical balance if the vocal or any of the musical instruments clearly goes beyond its sound plan, i.e. clearly stands out in terms of volume (pushed forward) or falls out of the “general line” in terms of volume (pushed back).
On track No. 13, the linearity of the sound path in terms of volume level, its macrodynamics and the ability to transmit a polyphonic sound image are evaluated. The phonogram contains a high-quality recording of a symphony orchestra, performed in the Great Hall of the Moscow Conservatory. The recording was originally digital (the sound signal was digitized directly after the microphones) in 24-bit/96 kHz format and after mastering was reduced to the standard 16-bit/44 kHz CD format. According to the sound engineer, the listener should be somewhere in the middle of the hall and feel the overall sound of the orchestra with maximum airiness and volume. Therefore, musicians are perceived as distant from the listener. The fragment consists of four main parts, differing from each other in volume level and dynamics. And the first part, which sounds very quiet (pianopianissimo), and the second (piano), and the loud third (forte), and the fourth, final (forte fortissimo), should be perceived equally naturally. The pizzicato of the group of string instruments in the first part, despite the low volume, should be crisp and clear, the listener can freely and clearly distinguish the "pinch" of the musicians' fingers. The solo brass instruments in the second part of the phonogram are light, distinct and well localized in terms of their location in the orchestra.
The third, loudest part of this phonogram is not at all simple for the sound path. Here the orchestra sounds very powerful. A group of cellos and double basses enters, giving grandeur to the sound of the orchestra. By ear, it seems that the overall picture, as it were, unfolds in front of the listener and visually slightly rises up. The perception of a large number of string and wind instruments should be polyphonic - remain pure and natural, where not only string and wind groups, but also individual instruments in them are legible and clearly audible. A sound path that is good in terms of dynamics transmits this part of the phonogram easily, musically and dynamically. It should not seem “blurry”, merge into a common “cloud” filled with tools.
Sound evaluation
1. It is considered unacceptable or hardly acceptable if the string pizzicato in the first part is completely unintelligible or sounds too quiet, sluggish and indistinct compared to the next, louder part.
2. It is considered unacceptable or hardly acceptable if in the third part (after the introduction of a group of cellos and double basses) there is no noticeable jump in volume (forte) and then, in the final, one more jump (forte fortissimo), in other words, the sound clearly lacks lightness, dynamics , energy.
3. It can be considered unacceptable or hardly acceptable when non-linear distortions are clearly audible in the third and fourth parts of the phonogram or there are no distortions, but the orchestra clearly does not reach forte fortissimo in volume.
4. It is unacceptable if the orchestra already in the third movement begins to sound like a common “mess”, to merge, separate groups of musical instruments are hardly distinguishable or these groups are completely indistinguishable.
Track 14. Additional track for evaluating the sound quality of the lowest audio frequencies. It is needed for sound paths capable of reproducing the lowest bass and working in acoustically treated rooms. The phonogram contains a nine-second fragment of the sound of a symphony orchestra, which includes a large (Turkish) drum with a very low register. It can only be heard with a high quality subwoofer that naturally reproduces frequencies of 20 - 25 Hz. For ease of evaluation, the passage is repeated three times in a row, and the Turkish drum enters the track from the 3rd, 17th and 32nd seconds.
Sound rating I
If you feel that from the indicated seconds a clearly distinguishable low bass beat is added to the sound of the orchestra every measure and the room does not hum, you can be congratulated from the bottom of my heart.
For the ON-LINE test of acoustics and audio system, the contents of the "FSQ AudioDoctor" disc, recoded to MP3 with maximum quality, are presented.
Online acoustics and audio system test
In 2006 "AVTOZVUK" magazine released the second version of the CD with test fragments. The second version contained the same 16 tracks for testing and tuning audio equipment to which additional tracks were added for finer tuning. Initially, the test fragments were in CDA format, which was the most optimal at the time of the release of the disc. However, the gradual death of this format forced them to convert these audio fragments to WAV. Thus, the quality was not affected, but the ability to copy test recordings to USB flash drives significantly expanded the options for using these tests.
The archive, packed with minimal compression, contains the contents of the "AudioDoctor FSQ 2" disk, which makes the archive more versatile, since it contains both versions of the disk.
Well, for a better understanding of what it is, a copy of the accompanying text from the "AudioDoctor FSQ 2" test disk is provided, which allows you to more accurately tune the acoustic systems and the amplifying complex:
FROM THE COMPILERS OF THE "AUDIODOCTOR-2" TEST DISK INTENDED FOR CHECKING AND SETTING UP ACOUSTIC SYSTEMS AND AUDIO EQUIPMENT:
This disc got its name in the most logical way. It's not just that this is a new edition of the most popular "test-configuration" CD in our country. The new edition of the disk with test signals for checking acoustics consists of two completely independent parts. Yes, they have different authors. In the first part, this is Dmitry Svoboda, in the second part, Andrey Elyutin.
PART ONE. DIAGNOSIS AND TREATMENT
Judging by the numerous reviews, we underestimated the level of competence of our readers. The first "AudioDoctor" was made on the basis of the judge's CD "Car Audio FSQ" with some simplifications. So, we increased the pauses between the tracks in order to leave more time for analyzing what was heard. We recorded the difficult-to-read tracks for checking the phasing of the audio path at low, medium and high frequencies repeated twice.
In the second edition of "AudioDoctor" it was decided to abandon this and return to the form that was included in the original FSQ test disk. Therefore, "AudioDoctor-2" is designed for fairly experienced listeners, which, apparently, are the majority of our readers. The selection of test tracks itself has not changed, since the original disc has been "polished" for six years to a generally recognized reliable and proven tool for operational acoustic expertise. However, to increase convenience and versatility when setting up the sound path, we decided to add several technical tracks. The content of the first 14 tracks has not changed, and here we refer the reader to the booklet published on the magazine's website to the first "AudioDoctor".
From the description of AudioDoctor FSQ 1
However, I would like to make some comments on these tracks as well. We already mentioned a nuance on track 10 (timer 1:07), where the drummer accidentally touched the cymbal with his elbow, but then, so that it would not ring, he clamped it with his hand. She managed to ring, very briefly and so quietly that you can only hear it on the sound path with a very high musical resolution. That's why we left this sound on the phonogram in order to use it as a test.
Judging by the readers' letters, this fragment solves its tasks more than successfully. In Krasnoyarsk, for example, two audiophiles, with the help of "AudioDoctor", staged a "review competition" of the audio equipment displayed on the counter in front of amazed sellers. Of the wide range of equipment offered there, only a few samples had really high detail. By the way, not the most expensive products... Another "zest" of this phonogram (timer 1:47) is the barely audible sound of a jumping drummer. The recording then was long and difficult, and after that, a successful double, the musician, having worked out the last blows on the cymbals, jumped up, full of musical ecstasy. This place turned out to be at the very end of the phonogram and could easily be cut out by the mixer during mixing. But we decided to leave this sound as a test one. And if you hear both of these sounds at a normal volume level, you can be justifiably proud of your equipment. What else is "hidden" in the tracks you already know? The notorious phonogram No. 9 consists of a "moving" drum from left to right and serves to determine the linearity of the width of the sound stage. But the same notation is very convenient to use to assess the crosstalk between the channels of the audio path, a very important parameter, but undeservedly overlooked. If when you move the drum to the right in those places where it just sounded, after-sounds are heard, beware - this may be a sign of insufficient crosstalk attenuation. If the echo of the seventh beat (rightmost) is heard not only in place of the fourth (central), but also the very first (left), then the crosstalk is clearly not enough, the stereo image will be blurry and unnatural. The main source of this defect in the audio path is the power amplifier. More about this track. The snare drum that sounds in it is structurally equipped with metal springs stretched outside the lower plastic (there are usually four to six of them). They, of course, contribute to the sound, which is why the frequency range of this instrument extends up to the very highest frequencies. Experienced FSQ experts on this drum sound can quickly and accurately assess the frequency response of the sound path. Practice, maybe you will succeed ... There is one more piece of advice regarding the assessment of crosstalk and plus the tendency of the amplifier to self-excitation. If a sweep tone played in one channel (tracks 5 and 6) has extraneous sounds in another channel (where there is no signal), then you have problems, you can expect a dirty, modulated sound and distorted sound perspective. This is a consequence of poor crosstalk between channels and self-excitation of the amplifiers. The first is the scourge of hastily made amplifiers, where the sound signal penetrates into the adjacent channel through the common power circuits or due to illiterate PCB layout. And self-excitation is already unscrupulous circuitry. In the worst case, spontaneous self-excitation (usually at the treble) can even burn out the tweeter.
Now about the technical tracks.
Track 15 is a recording of uncorrelated pink noise in both channels. Noise is a random process, and in this phonogram the processes in the channels proceed independently of each other. To the ear, such noise is perceived as a sound cloud of impressive size, hanging in the air. The first edition of "AudioDoctor" also had this track, but with in-phase pink noise. Correlated pink noise is now recorded on track 16 in phase and out of phase. In this case, the signal in the stereo channels is the same, common-mode noise should be focused between the speakers, and anti-phase noise should be smeared in space, trying to "stick" to the acoustics of one or another channel, which turned out to be closer.
On tracks 17 and 18 recorded pink noise, filtered by HPF with a cutoff frequency of 500 Hz, separately for the left and right channels. Practice has shown: it happens that in stereo mode phasing separately for HF, MF and LF (tracks 2 - 4) gives encouraging results, and listening reveals some unnatural sound. This may be due to the fact that in the left or right channel, the LF and HF emitters are out of phase with each other. For more accurate localization of low-frequency risers when placing left and right speakers in home premises, tracks 19 and 20 are used. They can also be used when setting up stereo subwoofers in car audio (this happens). The tracks are exactly the same as track 7, but recorded separately for the left and right channels.
PART TWO. HEARING TEST
Even the Scripture says: "Physician, heal thyself." For those who wish (we will not force anyone), we have supplemented the toolkit for setting up sound systems with a set of special audio tracks to assess the visibility of certain distortions sound signal or the ability of the listener to notice them. The specially processed signals for this part of the disc were mostly developed by the American Arnold Krueger as part of his research into blind comparative listening techniques. The tracks are very short, in order to completely exclude the short-term factor of auditory memory, but there are a lot of them, therefore, for the convenience of work, we recorded CD-text on this disc, and the content of each track is displayed (if it is provided for by your equipment) in abbreviated form - conditional. When describing tracks, we will give its designation on the display during playback. The degree of visibility of distortions artificially introduced into phonograms depends on their magnitude and nature and varies from "very easy" to "almost impossible". This, I mean, is subject to an impeccably working path and a very talented listener. You can learn a lot about both by experimenting with different paths (and/or different listeners) if you wish. Collective exercises with test fragments become especially exciting, when one of the listeners makes up the "blind" part of the audience; the compilers checked this both on themselves and on those who came to hand. On an enlarged basis, materials for "hearing test" are divided into three groups: frequency distortions of various mechanisms, non-linear distortions and noise.
FREQUENCY DISTORTION
Tracks 22-26 contain a phonogram consisting of two series of castanets. In each pair, the first fraction is the original recording, and the second is made through a low-pass filter with a very large steepness. You are invited to evaluate your ability to notice the bandwidth limit of the audio path from above.
Track 22 cutoff frequency 5 kHz LP 5 kHz very easy
Track 23 cutoff frequency 9 kHz LP 9 kHz easy
Track 24 cutoff frequency 12 kHz LP 12 kHz harder
Track 25 cutoff frequency 15 kHz LP 15 kHz hard
Track 26 cutoff frequency 18 kHz LP 18 kHz very hard
Track 27, like 21 before it, is used to pause between chapters and display information about the upcoming chapter on the display. Tracks 28-31 contain two sets of snare drum hits. In each such pair, the first series - the original, reference, the second - was recorded through a high-pass filter with a different cutoff frequency. The frequencies are frankly low (some are indecently low), but really experienced listeners catch this, they need a path with a wide band at low frequencies to be happy.
Track 28 cutoff frequency 50 Hz HP 50 Hz easy
Track 29 cutoff frequency 32 Hz HP 32 Hz harder
Track 30 cutoff frequency 20 Hz HP 20 Hz hard
Track 31 cutoff frequency 10 Hz HP 10 Hz almost impossible
Track 32 displays "TILT DOWN". This is what it is: a brass chord is taken. On each track, it is first played in its original form, and then - after passing through a path with a frequency response that has a uniform rise to the lower frequencies and the same uniform decline to the upper ones. Like a sloping straight line, the slope you notice will mean that your hearing is sensitive to skewed overall tonal balance.
Track 33 +5 dB at 20 Hz, -5 dB at 20 kHz Down 10 dB easy
Track 34 +2 dB at 20 Hz, -2 dB at 20 kHz Down 4 dB harder
Track 35 +1 dB at 20 Hz, -1 dB at 20 kHz Down 2 dB hard
Track 36 +0.5 dB at 20 Hz, -0.5 dB at 20 kHz Down 1 dB almost impossible
On the following tracks, the slope of the frequency response is opposite, with a rise to the upper frequencies (TILT UP). Please note: with the same amount of frequency distortion, the degree of visibility will be different.
Track 38 -5 dB at 20 Hz, +5 dB at 20 kHz Up 10 dB very easy
Track 39 -2 dB at 20 Hz, +2 dB at 20 kHz Up 4 dB easy
Track 40 -1 dB at 20 Hz, +1 dB at 20 kHz Up 2 dB harder
Track 41 -0.5 dB at 20 Hz, +0.5 dB at 20 kHz Up 1 dB hard
Tracks 43-46 illustrate the visibility of deep dips in the frequency response. A frequency band with a center at 4 kHz was cut out from the original phonogram (by a digital notch with attenuation of -100 dB). The width of the cut strip is different, as is the degree of visibility of such vandalism.
Track 43 bandwidth 1/2 octave -1/2 oct. very easy
Track 44 bandwidth 1/3 octave -1/3 oct. easily
Track 45 bandwidth 1/6 octave -1/6 oct. harder
Track 46 bandwidth 1/12 octave -1/12 oct. difficult
On tracks 48-51, a burst of constant height (+6 dB) with different widths is created on the frequency response.
Track 48 bandwidth 1/2 octave +1/2 oct. very easy
Track 49 bandwidth 1/3 octave +1/3 oct. easily
Track 50 bandwidth 1/6 octave +1/6 oct. harder
Track 51 bandwidth 1/12 octave +1/12 oct. difficult
Tracks 53-56 are dedicated to the visibility of the constant-width dip in the frequency response. A notch around the same frequency of 4kHz is created using a parametric equalizer with a quality factor of Q = 0.5, which means a bandwidth of about two octaves, and the depth of the notch varies.
Track 53 - 3 dB at 4 kHz -3 dB easy
Track 54 - 1 dB at 4 kHz -1 dB harder
Track 55 - 0.6 dB at 4 kHz -0.6 dB hard
Track 56 - 0.4 dB at 4 kHz -0.4 dB almost impossible
NONLINEAR DISTORTION
Track 58 recorded a 1 kHz tone with minimal non-linear distortion. On the subsequent ones - with artificially introduced distortions in the form of a typical mixture of harmonics. We don't give a rating of difficulty here, but you'd be surprised how early distortion starts to be heard on a clean tone.
Track 59 - 0.3% distortion at 1kHz THD 0.3%
Track 60 - 1.0% distortion at 1 kHz THD 1%
Track 61 - 10% distortion at 1 kHz THD 10%
The following tracks are dedicated to the visibility of harmonics in a musical signal. A second harmonic has been introduced into the short piano fragment, which distorts the symmetry of the signal. Please note: it is not so noticeable, even at a very high content.
Track 63 - Piano REF original recording
Track 64 - 2nd harmonic, 0.1% 2nd 0.1%
Track 65 - 2nd harmonic, 1% 2nd 1%
Track 66 - 2nd harmonic 10% 2nd 10%
A similar series for the third harmonic, it is much more noticeable.
Track 68 - Piano REF original recording
Track 69 - 3rd harmonic 0.1% 3d 0.1%
Track 70 - 3rd harmonic, 1% 3d 1%
Track 71 - 3rd harmonic 10% 3d 10%
A piece of a phonogram, to which noise with a predetermined level relative to the signal level is mixed.
Track 73 noise level -80 dB -80 dB
Track 74 noise level -70 dB -70 dB
Track 75 noise level -60 dB -60 dB
Track 76 noise level -50 dB -50 dB
Track 77 noise level -40 dB -40 dB
Track 78 noise level -30 dB -30 dB
The graphs show what type and what magnitude of frequency distortion was introduced into the phonograms on tracks 33-56. The name of each graph will appear on the display at the beginning of the section (if CD-text is being output), and the curve labels will appear as they are played.
The track descriptions of part 2 of the disc are given in the following format:
track number / content / CD-text / difficulty level
From the author of the test disc:
YOU PROBABLY NOTICED THAT people who are completely satisfied with the sound of their technique are not so common. Something is always wrong, as we would like, because of which we involuntarily have to listen to the advice of friends and sympathizers. But the perception of sound is subjective and purely individual, so it is pointless to follow such advice. The result can be paradoxical - by changing the components to others, as a rule, more expensive ones, you will not get the desired peace of mind. Therefore, it is best to deal with your problems yourself, and with a competent formulation of the problem, you can achieve success.
As you know, the main thing in the treatment of any disease is the correct diagnosis. The selection of the necessary medicines, potions, etc. - will be later. If you really want to enjoy music at home, the diagnosis of the sound image in general is as important as in medicine. By "in general" we mean the general perception of music, which depends both on the selection of audio equipment, cables and disks of the appropriate quality, and on the acoustic properties of the room itself.
It's no secret that the finest audio equipment at home may not sound. At the same time, in a good, acoustically adjusted room, the process of selecting components and their correct settings is greatly simplified.
The test disk "AudioDoctor FSQ" will facilitate diagnostics and correct setting home tract. The FSQ methodology is specifically designed for objective and subjective acoustic testing. We will describe in detail all the tracks and tell you what you should hear. And, of course, we will conduct a course of treatment if the sound is not all right.
The subjective-statistical method "Fast Sound Quality" (FSQ) was developed at the Acoustic Center of the Department of Radio Broadcasting and Electroacoustics of MTUCI for professional subjective-statistical examinations (testing) to assess the sound quality of the sound path. It makes it possible to obtain high reliability of results at low cost of expert time. The method includes an optimal selection of objective and subjective parameters that determine the sound quality, a test disc with specially selected and recorded phonograms, and a methodical development of listening.
In 2001, the method was adapted to assess the sound quality (SQ) in a car interior. An original expert (judging) protocol was developed and a test disk "Car Audio FSQ" was published. MTUCI began training qualified experts capable of listening (judging) sound in cars.
In 2002, the method was detailed at the 21st international conference of the AES (International Society of Acoustic Engineers), and the following year, the Car Audio section was organized at AES.
In 2003, the FSQ method began to be used to assess the short circuit of multimedia audio systems and studio professional monitors of the near field with its test disc "Multimedia FSQ" and expert (judging) protocol.
FOR REFERENCE
FSQ METHOD IS DESIGNED FOR PROFESSIONAL EXPERTS, however, its accessibility allows it to be used by experienced listeners as well. The main thing is to carefully study the phonograms included in the disc and the approach to assessing their sound. Do not be discouraged if the first time you do not hear the whole sound information- at first it's really not so easy. Most importantly, fully concentrate on the musical material, do not hesitate to repeat a fragment that is not entirely clear to you several times.
Now about what and how we will listen.
What - of course, your audio system and exactly in the place in the room where you usually are. We emphasize this on purpose, since the sound field in the room is not uniform, there may be places where hum and cross reflections occur.
But about how to listen, we will tell in detail.
Since there is no physical quantity that unambiguously describes the sound quality in nature, experts use various terms. From the most simple and non-specific "better", "worse" to more accurate "clear", "blurry". More correctly, these buzzwords are called subjective criteria. There are more than 100 of them, and many of them are non-specific or duplicate each other, which greatly complicates acoustic examinations and sometimes even levels the results. Attempts to unify terminology have been carried out all over the world for more than a dozen years, but so far they have not been successful.
The FSQ method clearly regulates the main and secondary subjective criteria for assessing sound quality. The main ones that will appear in the test disk "AudioDoctor FSQ" include:
Headroom for undistorted loudness.
The correctness of the phasing of the stereo audio path.
Unevenness of the amplitude-frequency characteristic (AFC).
Microdynamics of the sound path.
Macrodynamics of the sound path.
Natural timbre balance.
Natural musical balance.
The ability to linearly reproduce low frequencies.
The presence of noise and interference.
The linearity of the stereo image across the width of the sound stage.
The width and height of the sound stage, its position (orientation) in the horizontal and vertical planes.
Sound stage depth (separation).
The naturalness of the transfer of musical attack.
Linearity of the stereo image at different volume levels.
The ability of the audio path to transmit polyphony.
A solid list, but it's not as difficult as it seems. The phonograms on which these assessments will be made are very accessible for perception. Don't be embarrassed that at first you will have to stop often and listen to fragments of the FSQ Audio Doctor. Practice shows that after four or five listenings, most of the difficulties disappear.
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