source file: mills2.txt Date: Mon, 25 Sep 1995 08:19:24 -0700 From: "John H. Chalmers" From: mclaren Subject: Tuning & psychoacoustics - post 2 of 25 --- Many and strange are the myths which afflict so-called "modern" music theory, particularly when it comes to the operation of the human ear. Most of these tall tales have been handed down to present-day musicians from the 19th century, although some of the myths date from much earlier--as early as the number mysticism of Pythagoras, the Babylonians, the Egyptians, and of Hindu astrology. Shockingly, typical "modern" music theory texts cite Helmholtz, Rameau and Mersenne as the sole authorities on acoustics and psychoacoustics--or they cite other "modern" music theory texts which cite only these musty & antique sources. This is comparable to a "modern" science text citing Lagrange, Hamilton and Newton as authorities on the nature of subatomic physics. A physics professor who wrote such a book would be laughed out the profession--but for some reason this practice is acceptable in music. Together, this antique trove of musical old wives' tales and acoustic "just-so stories" constitutes a body of misinformation which has been handed down through textbooks which thoughtlessly draw on older textbooks, until the chain of errors reaches back through 3 centuries or more. Partch has illuminated a few links in this monumental chain of fabulation and compounded error, but the amount of misinformation is far larger than even he could ever have suspected. --- Every statement presented in this series of posts as fact will be supported as far as possible by references from the scientific literature. When subscribers to this forum violently attack these posts--as no doubt they will--the interested reader is advised not to rely on *my* bare assertions *or* the unsupported claims of those who say "it's [a lie/ignorant/wrong, etc]" Rather, the interested reader is advised to go to the original reference sources. Read them. Search out the audio tapes & CDs specified below. Listen to them. And finally: perform your own experiments with Csound or a synthesizer, using your own ears and a computer. This last point is *crucial.* You will need to perform true double- blind tests on your own hearing to obtain valid conclusions. If you concoct a set of test tones and listen to them *knowing* what they are, your ears will lie to you and you will literally not be able to hear the test tones and acoustic examples objectively. Only by using a true double-blind procedure can you reliably ascertain what your ears *actually* hear, as opposed to what you *think* you're hearing. This is why the most common objection to the facts of modern psychoacoustics--"I don't hear it that way!"--is utterly meaningless. Without A-B-X double-blind tests, none of you can tell what intervals you prefer (nor can I) because the knowledge of what you *think* you're listening to and what you *expect* to hear contaminates and alters what you hear. --- This point is so important that it is worth an example: "The extent to which observers can persist in the same error of observation was shown to me by the following experiment. High-fidelity fans complained about the nonlinear distortion in a certain sound-transmission system. To test the maximal distortion these listeners would tolerate, an induction coil was made with an iron core that was highly overloaded and produced nonlinear hysteresis distortion. A second coil containing no iron was combined with the first in such a way that only the pure distortion remained. Musicians were delighed with this system, which made tenors' voices sound metallic and heightened the dynamics of the orchestra. Their adjustments of the system to optimal sound had about 70% pure iron distortion." [von Bekesy, G., "Hearing Theories and Complex Sounds," Journ. Acoust. Soc. Am, 35(4), April 1963, pg. 589] Without an objective reference and an independent means of measurement, *we do not know what we hear.* Over the course of this series of posts, it will become clear that the ear sometimes adds to, sometimes subtracts from, and always changes the information that enters our auditory system as sound waves. For example: [1] Highly trained symphony orchestra musicians reglarly perform intervals as small as 683 cents and as wide as 725 cents, yet hear them as "perfect fifths;" ["Some Aspects of Perception - I," Shackford, Journ. Mus. Theory, Vol. 5, 1961, pp. 13-26] [2] So-called "perfect" intervals, including the octave and 3/2, can sound dissonant or consonant depending on the range in which they sound, even if they use harmonic-series timbres; ["The Science of Musical Sound," Sundberg, 1992, pg. 73] [3] Pitches transposed up an octave can be heard by musically trained listeners as dropping slightly in pitch; ["The Science Of Musical Sounds," Pierce, 1992, pg. 214] [4] Tones of specific pitch can be heard by musically trained listeners when in fact no tones are physically present; and tones can disappear and become inaudible to the ear/brain system even though they're presented to the ear at high amplitude; ["Psychoacoustics: Facts and Models," Zwicker & Fastl, 1993, pp. 91-135; "The Perception of Musical Tones," Rasch and Plomp, pp. 1-21, in "The Psychology of Music," ed. Diana Deutsch, 1982; "The Science of Musical Sounds," Sundberg, pp. 48-86.] [5] The ear/brain system can generate audible illusions which convince the listener that s/he is hearing paradoxical and impossible sounds--sounds which simultaneously speed up and slow down, for instance, or sounds which simultaneously rise and fall in pitch; or sounds which rise endlessly in pitch, or fall endlessly in pitch; ["The Science of Musical Sounds," Pierce, pg. 215; "Structural Representations of Musical Pitch," Shepard, in "The Psychology of Music," Ed. Diana Deutsch, 1982, pp. 334-373.] [6] There is a universal human craving for stretched intervals, which leads highly trained musicians to perform so-called "perfect" intervals consistently wider than the ratios by which "everyone knows" these intervals are defined; ["The Science of Musical Sound," Sundberg, pp. 104-105, "Introduction to The Physics and Psychophyics of Music," Roederer, pg. 155] [7] The ear/brain system detects pitch in a complex way still not fully understood, with the result that the pitch of a complex sounds is perceived to change with the loudness of the sound, the amount and onset of noise masking the sound, the type other harmonic sound played simultaneously, the degree of harmonicity of the partials in the sound, the length of the sound being played, the spectral centroid of the sound, and the suddeness of onset of the sound; ["Experiments On Tone Sensation," Plomp, pp. 127-129; "Introduction to the Physics and Psychophyics of Music," Roederer, pg. 135; "Perception of Timbral Analogies," Wessel & Ehresman, Rapports IRCAM 1978, pp. 1-29, Pickles, James O., "An Introduction to the Physiology of Hearing," Academic Press, 1988, pp. 270 ff., etc.] [8] Many of the inner workings of the ear/brain system are still unknown, and each of the conflicting theories of how the ear/brain system hears is supported by some psychoacoustic evidence, but contradicted by the rest. ["Experiments On Tones Sensation," Plomp, pp. 49-52; "The Science of Musical Sound," Sundberg, pp. 100, 186; "The Science of Musical Sounds," Pierce, pp. 101, 113-114; "Rapports IRCAM - Musical Acoustics," Risset, 1978, pg. 8; "Introduction To the Physics and Psychophysics of Music," Roederer, 1973, pp. 130-133] --- All of which points to the conclusion that the ear/brain system is *complex.* There is no simple explanation for how we hear. The ear/brain system generates false information, destroys some of what comes into our ears, and transforms all of it, either subtly or grossly. Yet the single common thread that will run through all the so-called "rebuttals" and attacks on this series of posts will be: THE EAR IS SIMPLE. "Helmholtz explained it all," one person will yelp, while others will screech "Terhardt explained it all," or "Backus' book tells you everything you need to know!" The interested reader is advised, again, not to believe me *or* to believe those who attempt to rebut me. Rather, the interested reader is advised to *study the psychoacoustic literature,* excerpts of which and references from which will be listed extensively in every post. Only by doing this can the objective reader get a real sense of the extraordinary complexity of human hearing, and the self-evident falsity of claims that "the ear is simple" and "Helmholtz explained it all in 1863," and "my 1939-vintage references don't say that." Do not lend your credence thoughtlessly to *any* statement without *testing for yourself* the evidence (or lack thereof) for that statement. Wisdom does not arise from credulity, but from doubt. --mclaren Received: from eartha.mills.edu [144.91.3.20] by vbv40.ezh.nl with SMTP-OpenVMS via TCP/IP; Mon, 25 Sep 1995 17:21 +0100 Received: from by eartha.mills.edu via SMTP (940816.SGI.8.6.9/930416.SGI) for id IAA21245; Mon, 25 Sep 1995 08:21:28 -0700 Date: Mon, 25 Sep 1995 08:21:28 -0700 Message-Id: Errors-To: madole@ella.mills.edu Reply-To: tuning@eartha.mills.edu Originator: tuning@eartha.mills.edu Sender: tuning@eartha.mills.edu