CONCERT HALL ACOUSTICS
©1982 The Anstendig Institute, Revised 1984
(This paper should be read in conjunction with The Anstendig Institute's papers on sound equalization and hearing, which are available upon request.)
The acoustics of any hall, as perceived by a member of the audience, consist of three factors: volume, equalization, and reverberation (i.e., reflected sound).
Volume, easily understood as the loudness of sound, needs clarification in relation to acoustics. Technically, volume is referred to as sound-pressure-level and is measured in units called decibels. Subjectively, one decibel is the smallest difference in loudness that the human ear is supposed to be able to perceive. Objectively, six decibels is the amount sound becomes louder or softer if the distance from the sound source is halved or doubled.
In a concert hall, the sound one hears consists of 1) directly radiated sound and 2) reflected sound.
1) Directly radiated sound, referred to as primary sound, is the sound that reaches the ear directly from the source.
2) Reflected sound is the sound that reaches the ear after being reflected off the various surfaces of the hall (walls, ceiling, etc.). It is usually confused with and mistakenly referred to as reverberation.
Although the sound one perceives consists of both primary sound and reflected sound, the primary sound determines the perceived volume level. This is appreciably louder because 1) sound becomes softer in proportion to the square of the distance traveled and the reflected sound travels a much longer distance, and 2) sound is partly absorbed and diffused by the reflecting surface. Therefore, reflected sound normally plays a negligible role in the actual perceived volume level.
Primary sound and reflected sound are essentially two separately arriving sounds of different volume levels. A characteristic of hearing is that the loudness of two sounds of different volume is not perceived as the sum of the two. The combined sounds are perceived as being only as loud as the louder of the two sound-sources. The louder sound determines the apparent volume level; the less loud sound does not add appreciably to the perceived volume level. This can be demonstrated in a room with four speakers, one in each corner. If the speakers play with unequal volume levels, the sound will always seem to be coming from the direction of the loudest speaker even with differences in volume as small as a few decibels. It only becomes obvious that the other speakers are playing if they are switched off.
In everyday life, most sound-environments are full of sound-absorbing objects and materials and, because one is usually close to the sound source, reflecting surfaces are proportionally much farther away. Therefore, the ear is conditioned to hear a relationship of primary to reflected sound in which the volume of the reflected sound is so much lower than the primary sound that one is not aware of it. This apparent relationship between the volume of direct and reflected sound must be preserved if the sound in a concert hall is to seem natural. Because one is quieter, calmer, more relaxed, and more concentrated than usual during a concert, perception of subtleties is heightened. Therefore, for the sound to seem natural, the proportionate volume level of reflected sound relative to primary sound must be somewhat less than in real-life.
Equalization is essentially a further delineation of volume. Sound consists of vibrations (frequencies) of different speeds (cycles per second, or Hz), from approximately 20 Hz to 17,000 Hz, with most sounds lying within 40 Hz to 12,000 Hz. The equalization of sound is the volume of all the frequencies in relation to each other. If the equalization of a hall is correct, a sound from the stage in which all frequencies are equally loud will reach the audience in exactly that same volume relationship. If the volume level of some frequencies in relation to the others is changed when the sound reaches the audience, the hall is unequalized and does not radiate all frequencies correctly. In other words, the equalization of a hall is a function of volume in that it deals with whether the different frequencies reach the audience in their original volume relationship to each other, or whether the hall distorts that original balance, transmitting some frequencies more strongly than others.
How sounds radiate from their sources (their dispersion characteristics) differs over the frequency spectrum. Lower vibrations radiate almost equally in all directions, while higher frequencies radiate more directly in straight lines. Because strongly reflective surfaces usually change the frequency balance in favor of the more directly radiating higher frequencies, the reflecting surfaces of a hall have to be carefully designed to not change the equalization. That holds true for the directly-radiating surfaces of the stage as well as the reflecting surfaces of the hall.
Ideally, a concert hall should not favor the high frequencies, but should have a mellow, warm sound, i.e., it should slightly subdue the higher frequencies. The more mellow the sound, the more freedom the musicians have in the manner in which they can produce and articulate the sounds. The less the hall highlights the higher frequencies, the greater the range of dynamics (from triple-pianissimo to triple-fortissimo) and the more types of attack (from sweet dolce to vigorous, biting accents) the musician can make use of while retaining beauty of tone. But, in a bright hall, all hard accents and biting attacks sound overly harsh and stringent. The sound in loud passages has a harsh, biting edge. To compensate, the musicians have to avoid the more vigorous, biting attacks and accents, and the dynamics have to be kept down if the sound is to remain listenable. The strings, for example, cannot really "dig in" and play full out with plenty of bow-pressure and a big tone. If they do, the sound is hard, harsh, and edgy.
Equalization is the most important single factor in any acoustic, and, in fact, in sound itself. It is the factor that most obviously changes the quality of a sound. Anyone with a hi-fi system that includes an equalizer can easily find this out by observing the differences in the sound when the frequency balance is changed. But, for decades, people have been hearing grossly unequalized, distorted sound reproduction (recordings, live broadcasts, live sound reinforcement).1 They have been conditioned to ignore the distortions of unequalized sound, have become used to them, and thus do not notice that, in a bad acoustic, the equalization is inevitably the worst factor.
REVERBERATION and REFLECTED SOUND
Reverberation is the most misunderstood and least important of the factors. Reverberation is the process of the reflected sound bouncing back and forth off all reflecting surfaces until it stops. The word "reverberation" is the wrong term to describe what is actually heard. The sound quality that is heard and called reverberation is actually the result of only the first-arriving reflected sound. These sound effects, wrongly referred to as reverberation, are understood and discussed only in terms of reverberation time, but actually consist of two other factors: volume and reflection time.
The more important of these factors is the volume. If the reflected sound is so soft as to be covered (masked) by the primary sound, it will obviously not make the slightest difference except in the pauses. The time factor only plays a role when the volume of the measured reverberated sound is loud enough to be perceived, however subtly, by the listener. In a concert hall, the important point to remember is that the volume of reflected sound should not be loud enough to be consciously heard, even when the tensions of the body have relaxed and the listener is hearing very loudly.2
The characteristics of primary sound do not change. Therefore, the first-arriving reflections determine the character of a hall's acoustic because they are the only reflected sounds loud enough to affect the sound's characteristics.
The simple mathematical difference between the arrival-time of the primary and reflected sound is the pertinent time-factor in acoustics: reflected-sound-time minus primary-sound-time equals reflection time. This interval is purely a function of the size and shape of a hall. Reflected sound can also be measured from the source, in which case it becomes simply the time it takes for the sound to travel to the reflecting surface and back to the source. This measurement indicates how the performers, not the audience, experience the sound.
The concept of "reverberation time" as a meaningful acoustical measurement is wrong. It does not represent actual listening experience. In actual listening, there is no one single time for reflected sound to reach a listener. All sounds continue reverberating back and forth off all surfaces until they die down to absolutely nothing. But we can only perceive the reverberating sound while it is still loud enough to be heard. The misunderstanding stems from the measuring technique.
The value stated as the reverberation time is an arbitrarily chosen value that is supposed to represent the point at which the reverberating sound has died down to a volume level so weak that it essentially is no longer present (1/1,000,000th of the original volume). In a hall with a measured one second reverberation time, the sound would actually lose approximately 75% of its loudness in the first 1/lOth of a second. It would be almost instantly covered by the continuing sounds of the music and, in pauses, will be covered by the room's natural noise level (ambient sound) long before it becomes 1/l,OOO,OOOth of its original volume. The measuring instrument registers the first-arriving (direct) sound and then records the length of time it takes for that sound to die down (decay) to that irrelevant, insignificant volume level. But this measurement is worthless because it neither tells the actual time it takes for the reverberations to stop nor does it tell anything about the really important, bearable sound events that happen in between. Any effect the reflected sound would have on the acoustic qualities of that room would happen long before the measurement was reached.
Although no instrumental measurements can duplicate the way the reflected sound is actually perceived, they can provide helpful information. A more difficult, but more meaningful measurement for acoustical evaluation would be to measure the time-interval between the first arrival (direct sound) and the very next few arrivals (the first-arriving reflections) along with their volume-levels. Careful tabulation of that information for a large number of concert halls would probably lead to insights into the real differences between good and bad halls.
The first-arriving sound reflections are necessarily the loudest. But it is impossible to establish a single reflection time. The reflecting surfaces are at differing distances from the listener. Sound reflected off the ceiling, the side-walls, the back wall, and the wall behind the performer will reach the listener at different time intervals since each of these surfaces (even each segment of the surface) is at a different distance from the performer and the listener. Also, a measuring instrument has no way of telling whether the sound reaching it is a first arrival from a far wall or a second, third or fiftieth arrival from a near wall. Since all of the bearable reflections arrive so quickly, they amount to a steady sound made up of the many arrivals of reflected sound which are so close together that they cannot be registered separately.
There is a prevalent misunderstanding that reverberation is something beneficial that can be added to sounds at will within a wide range of parameters. Reverberation is really a PROBLEM that has to be controlled, and not a benefit for which it is only a matter of finding the ideal amount, and the more the merrier.
What reverberation amounts to is repetitions of progressively more and more distorted reflected sound because no surface reflects all frequencies equally. When loud enough to be heard, the effect of these reflections is similar to the effect of reprinting the same picture a number of times on top of itself, with each reprint shifted slightly and the color-values changed. The result on paper is a blur, and conically the result of repeated, bearable reflections is also a blur. The prevalent idea that a long "reverberation time" can be excellent for a Mahler symphony but wrong for the speaking voice (because speech would be rendered unintelligible) is not valid. If the reflections blur speech, they will also blur the Mahler symphony. The problem in recognizing this fact is that, in the Mahler symphony, it is the most subtle nuances, which are the most difficult-to-hear aspects of sound, that are blurred. We are seldom able to be aware of all the subtleties of nuance in fine music. It is therefore difficult to know that those nuances have been eradicated, and a regular audience quickly becomes used to music without them.
In Davies Hall, the main problem with the reflected sound is that it is too loud, not that the reverberation time is too long or too short. A single measurement of the hall's reverberation time is meaningless since all four walls, the ceiling, and the reflectors (which amount to a sixth, irregular, reflecting surface) are made of materials with unnecessarily strong reflecting characteristics. Each of these variously distanced surfaces reflects the sound audibly enough to cause blurring and an exceedingly uneven equalization.
Instead of simply trusting the instruments themselves to radiate into the hall, the design of Davies Hall relies on reflections to distribute the sound. Such a design is doomed to a sound that is blurred, unequalized, and has no resemblance to the sound environments we live in. All the surfaces of the stage are as shiny and reflective as could be achieved without simply installing mirrors. Since the stage is set forward into the hall and has its own low reflecting wall behind the players, the back wall of the hall becomes an extra reflecting surface. As opposed to a conventional design, this arrangement produces an extra set of strong reflections that further confuse the sound. In an attempt to distribute the sound evenly throughout the hall, the reflecting surfaces are designed in convex forms and incorporate added convex-shaped disks molded into them at key reflecting points. The hanging reflectors are also convex. This diffuses the sound and ruins much of the focus that the players attempt to achieve in their tone production.
The effect of the excessive, overly loud reflections in Davies Hall is a muddying of textures from the many arrivals and a predominance of overtones, particularly in the mid-range (approximately 200 to 2000 Hz). This is similar to the blurring that occurs with overuse of the sustaining pedal of the piano. In fact, during a piano recital, Claudio Arrau, who has an excellent ear for balances, was forced to use either little pedal or no pedal at all in order to keep the textures clear, more so from mid-keyboard on up than in the bass, which sounded proportionally weak.
Davies Hall uses baffles to supposedly change the reverberation time. But they do nothing of the sort: the real reverberation time is a fixed physical entity almost infinitely longer than the times that are measured. It is determined by the distance the sound travels back and forth among the reflecting surfaces in relation to the point of reference. The baffles in no way change these distances. They also cover only a small percentage of the reflecting surfaces of the hall. What the baffles do is absorb some, but not all, of the sound that would be reflected by the sections of the walls they are shielding. This somewhat reduces the volume of the reflected sound and causes the instrument measuring the so-called reverberation times to register a shorter interval. But the length of time for a sound to truly die out remains essentially the same and the timing of the more important first-arriving reflections remains the same.
The baffles do slightly reduce the volume of the reflections, but mainly in the areas most affected by the covered wall surfaces. This, in turn, changes the equalization of the hall somewhat for the better by slightly reducing the high-frequency sizzle and clarifies the sound a little bit by reducing the blurring. The point has already been made that an acoustic that blurs one type of sound will blur all others. The baffles should therefore be left down all the time, and more of them on all of the walls would probably improve the acoustic immensely. But that could be better accomplished by simply reducing the reflectivity of the walls.
The generally encountered opinion that Davies Hall has an overly bright acoustic is correct.
A hall's acoustic is "bright" when an unequal transmission of the frequency spectrum favors the higher frequencies, i.e., in traveling from the stage to the listener, the balance of the higher to the lower frequencies changes, the higher frequencies becoming louder in proportion to the lower frequencies. In Davies Hall, this greater proportion of high frequencies peaks in the 2500 to 5000 Hz range, which is unfortunate because of two natural phenomena: 1) the sensitivity of our hearing is greatest in this range, becoming greater with increasing volume and 2) the overtones of most instruments, and especially the human voice, peak in this range (2500 to 3500 Hz). Since Davies Hall is a loud hall, the effect is that the music sounds harsh and expressively undifferentiated. In a vocal concert, for example, the voice has a harsh, raspy, grating "edge", which is a frequency peak at 2500 to 3500 Hz (male voices peak closer to 2500 Hz and female voices closer to 3300 Hz).
The distortion of the frequency balance in favor of the overtones detracts from the expressive effect of the music. Musicians play fundamental tones, not overtones. They do not think or conceive of music in terms of overtones. The fundamental tones, not the overtones, carry all the expressive, human nuances of the music. Therefore, the exaggeration of the overtones in Davies Hall reduces the expressive content, degrades the emotional experience inherent in the music, and robs it of many characteristic, human qualities.
In Davies Hall, the very high frequencies are not as exaggerated as the 2500-5000 Hz range. In fact, there may be a problem of transmitting the highest frequencies. The cymbals and triangle, for example, do not have enough of a high-frequency sheen. But the highest frequencies would become more prominent if the thickness due to exaggerated overtones were reduced. The bass fundamentals, which are not reinforced by the exaggerated overtone structure, are weak and suffer the most from the diffuse character of the hall's acoustic. The tuba, in particular, which radiates upwards into the reflectors, sounds so diffuse that it is a musical equivalent of the proverbial something hitting the fan and splattering all over the hall.
In listening for oneself, one should bear in mind that the brightness one experiences in Davies Hall, which a musician would refer to as being in the high, or upper, registers, would be referred to in hi-fi language as the "lower-highs" or "upper-mid-range". A high note on an instrument seldom exceeds 2000 Hz (high C is about 1040 Hz), but when an acoustics or electronics technician refers to "highs", he generally means frequencies well above 5000 Hz.
As a result of the strongly reflecting surfaces, Davies Hall is a loud hall. Even the auditorium itself is loud. Although a carpet has improved the auditorium somewhat, coughs and other audience noises are still more audible than necessary. Since hearing is much more forgiving of sound distortions at lower volume levels, the loudness of the sound in Davies Hall is a major aggravating factor in the bad acoustic. A loud volume level is not only unnecessary for a deep musical experience, it can even be detrimental. The frequency peaks are more disturbing. With a more subdued volume level, the audience has to calm down and become attentive in order to better hear details. A hall should not have so low a sound level that it is difficult to hear. But modern halls have such a loud volume level that the audience does not realize the need to settle down and become still in order to hear acutely. The abrasiveness of the resulting irritations and distortions keeps them on edge, making it difficult to relax and settle down.
THE PROBLEMS OF DAVIES HALL DUPLICATE THOSE OF RECORDINGS
It is obvious that Davies Hall has been built by people whose ideas of what music should sound like have been influenced by recordings. The distortions in the equalization of the hall occur in very much the same parts of the frequency range as the distortions of unequalized recordings.3 The idea of using baffles to alter the reverberation characteristics of the hall at will obviously comes from a type of electronic device, variously called a Time Delay System or a Reverberation System. These systems introduce, during sound reproduction, a repeat of the original signal. The time between the original and the delayed signal can be varied at will. This added signal is supposed to have the same characteristics as the reverberated sound in a concert hall, which is impossible, since it is only one repetition of the sound as opposed to the many reflections in a hall. The signal also cannot duplicate the changes in equalization that occur when sounds are actually reflected. In reality, all that these devices accomplish is to muddy and blur the sound. They in no way duplicate real reflected sound. Nevertheless, sound systems of this type are often used in the actual preparation of recordings and were even incorporated in concert halls as soon as they were developed. These systems are obviously the source of the utterly mistaken idea that reverberation TIME can be changed without actually physically changing the dimensions of the hall, i.e., without changing the distances the sound has to travel. They probably also have much to do with the acceptance of a blurred sound among acoustic technicians.
The acceptance of a highly diffused, unfocused type of sound quality as correct also stems from stereophonic sound-reproduction. Stereo is an impossible, irrelevant attempt to reproduce the way we hear a sound. It is only possible to reproduce the characteristics of the sound source itself.4
The fact that concert halls have been and are being built to sound like the flaws of unequalized music has created a vicious circle. Sound buffs attend concerts in these halls to check the accuracy of their sound systems. Of course, the halls sound very much like their systems. At the same time, performers who listen to unequalized recordings, which degrade the delicately refined expressive nuances, start to mimic the sound of those recordings. The home-listener hears something very similar to the concert he has just attended and thinks his system is marvelously accurate. Because this mess keeps music from fulfilling its greatest potential of uplifting us into the finest realm of experience, the conclusion must be drawn that it is dangerous to listen to music in Davies Hall.
The danger is not simply a matter of a bad acoustic in the auditorium ruining well-played music on stage. First, the playing can never achieve the musician's potential because the musicians are crippled by the various acoustical problems. Thus the desired "magic" of a performance cannot happen. Secondly, because simultaneous, direct comparison with correct-sounding music is impossible, we accept and become accustomed to (conditioned to) a wrong sound image and anticipate that image at future performances. When one's mind and body are set in anticipation of hearing a particular interpretation, it is nearly impossible to accurately hear a different one. Better to do without than to ruin one's frame of reference by developing and accustoming oneself to wrong listening habits. Once ingrained, those habits are almost impossible for most people to change. This is particularly tragic for young people since first impressions are the strongest determining factors in their development.5
HOW TO CORRECT THE DAVIES HALL'S ACOUSTIC
It is desirable to find out as precisely as possible what the characteristics of the hall presently are. While mechanical measurements do not duplicate actual live experience, if used by someone who understands the differences between the measuring of room acoustics and the measuring of actual music, they could provide valuable insights into the dispersion characteristics and the equalization of the hall. But they must be made under real-life circumstances, i.e., with an audience present. Such measurements are a prerequisite for any systematic attempt to correct the hall's acoustic.
That Davies Hall is a loud hall makes correcting it feasible. The steps necessary to correct the reverberation and equalization problems would lower the volume level, but there is ample leeway to do so without adversely affecting the musical experience. Substantially reducing the reflectance of all reflecting surfaces might solve the basic problems. Some experimentation might be desirable to determine whether or not the reflectance of all surfaces should be reduced equally.
The auditorium itself is too live, but the edginess and emphasis of overtones is also caused by the high reflectance of the stage. The apparent lack of fundamental bass is probably due to the overabundance of overtones in which case reducing the reflectivity of the surfaces could also solve the problem of the bass fundamentals. The protrusions of the back wall of the stage, which further diffuse and confuse the sound, would be unnecessary if the reflectance of the stage were lowered.
Sound becomes softer in relation to the square of the distance from the source to the hearer (the square of the distance the sound travels). The musicians' ears are next to their own instruments and in the midst of the other instruments around them. They normally hear primary, direct, unreflected sound and adjust their playing to those sounds, not to the reflected sound, which, in most halls, is too soft to be heard by the time it returns and arrives too late to be taken into consideration by their reactive responses. The extremely shiny surfaces of the stage and its back wall change this normal relationship so that certain players who are closer to the wall hear more reflected sound than other players and much more than they are used to hearing. The even shinier reflectors, which are much closer than a normal ceiling, have a similar effect.
In Davies hall, orchestra members complain that they have problems hearing each other. The complex problem of whether or not the musicians can "hear themselves" in a hall is mainly a problem of balancing the sound of distant players with that of players close by. The problem is complicated by the differences between the way the musicians hear themselves in a bad hall and the way they are used to hearing themselves. The usual method of trying to deal with this problem is to use overhead sound-reflectors which, in addition to helping the musicians hear themselves, are used to help distribute the sound evenly throughout the auditorium. This is a misunderstanding of acoustics. Since reflection times are a function of the size and shape of a hall, the artificial introduction within a hall of additional reflecting surfaces to conduct the sound can only make the sound more confusing. The characteristic qualities of a sound are determined mainly by the shape of the source and the shape of the space in which it is vibrating. Reflectors are foreign objects that are not part of the shape of a hall. They add additional time-delayed arrivals which confuse the ear and are unnatural to the sound qualities inherent in the hall's proportions.
The way the orchestra hears itself would be improved by drastically reducing the reflectance of the stage, eliminating or drastically reducing the number of reflectors, and enlarging the stage so that the back members of the orchestra can be much farther away from its back wall. This would also improve an additional problem, that the orchestra members hear the sound differently from the way the audience hears it. When the sound seems right to the orchestra, it does not sound so in the auditorium.
A good acoustic with the sound dispersed evenly throughout a hall depends on 1) each seat receiving direct sound, which means having a direct view of the stage, and 2) the reflections remaining substantially below the volume level of the direct sound. The use of reflectors only raises the volume of the reflections and introduces other, new anomalies. The proper way to proceed is to do whatever is necessary to correct the hall without any reflectors, and then, only as a last resort, add a minimum of reflectors for the musicians to hear themselves, if absolutely necessary. Reflectors should not be used to improve the acoustics of the auditorium.
Probably the classic forerunner of the low-budget, Davies-type hall is the Berlin Philharmonic Hall, the "Philharmonie", which was one of the first to use reflectors. But the reflectors were not used to help the acoustic of the hall itself. The hall was not designed with reflectors, but the orchestra complained that they could not hear themselves as well as they should. Some judiciously placed reflectors seemed to help that problem, which was not as serious as in Davies Hall. An important point is that the orchestra in the "Philharmonie" does not sit immediately in front of a highly reflective, polished wall, as in Davies Hall.
was designed by one of the greatest geniuses of the famous Bauhaus group, who
designed it around an extraordinarily harmonious geometric pattern and allowed
no compromise in that shape. The angles of the geometric pattern of the walls
(reproduced on the cover of recordings made in the hall) do not direct the
reflected sound as unremittingly towards the listener as those of Davies Hall
nor do they diffuse the reflected sound as much. The inside of the auditorium
is an artistic masterpiece that perfectly sets the tone (mood) for the
experience of music, easing the audience into the necessary state of calm
relaxation. The mood set by the visual impressions is an important point in a
hall's success. But even in the "Philharmonie", the seats behind the
orchestra never had good acoustics and still do not. After the experience of
A good acoustic (or any acoustic, for that matter) is essentially a product of the shape of the room. A room that does not have harmonious proportions will never have a good acoustic, no matter what one does with it. While a person sitting in the orchestra section of Davies Hall might not have as strong a feeling of harmony as in some past architectural masterpieces, one certainly does not feel uncomfortable with one's general impression of the shape and proportions of the hall. This leads to the conclusion that the hall could be considerably improved. Ideally, along with changing the reflectivity of the walls, the seating behind the stage should be abandoned, the back wall of the stage eliminated, and that area either left open or reconstructed solely to act as an evenly radiating horn for the sound from the stage.
The acoustic of a concert hall can only be best in ONE particular part of the hall. Trying to design equal, perfect coverage for all seats is an impossibility that, at best, can only result in a mediocre acoustic for all and more often results in an overall bad acoustic. That particular "best" part of a hall can only be the most central section of the center-orchestra section. If that central part of the audience has an excellent acoustic, the rest of a well-designed hall will have the best chance of being good. If that central part of the hall is faulty, there is NO chance of the acoustic being really good anywhere else. Some other sections might, by accident, be a little better, but the collective experience possible with music in a good acoustical environment will not happen.
The most sensitive measuring instrument by far is the human being. But the more sensitive an instrument, the more one must know precisely how to direct the measurements and the more care that is necessary. Mechanical instruments cannot replace the ear in devising, evaluating, tuning, or correcting a concert hall.
The senior acoustician of Davies Hall, Robert B. Newmann, said that "the acoustic of every new concert hall is an experiment" in that the acoustician never knows beforehand how it will turn out. That should not be the case. The morass of misunderstandings and wrong concepts prevalent among concert-goers and acousticians is fatal to building halls with the excellent acoustic one should be able to expect with today's technology. The first step is to know what to listen for and how to preserve the ear's sensitivity. An understanding of the concepts set out in this paper is essential.
1 See our papers on sound equalization.
2 See our paper "Sound Equalization" for a description of how hearing changes in relation to the relaxation of physical tensions during the course of a listening session.
3 See our papers on sound equalization.
4 See our paper "Stereo, a Misunderstanding".
5 See our paper "Our Conditioned Responses to Music."
The Anstendig Institute's other papers on acoustics and equalization, which are available to the public free of charge, help the public understand what to listen for. They explain in non-technical terms the factors involved in acoustics, sound reproduction, and hearing, putting these elements in proper perspective and clarifying many misunderstandings. Their purpose is to provide a knowledgeable basis for forming one's own opinion.
The Anstendig Institute is a non-profit, tax-exempt, research institute that was founded to investigate stress-producing vibrational influences in our lives and to pursue research in the fields of sight and sound; to provide material designed to help the public become aware of and understand stressful vibrational influences; to instruct the public in how to improve the quality of those influences in their lives; and to provide the research and explanations that are necessary for an understanding of how we see and hear.