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Re: effects of musical experience on pitch perception?

Hello Daniel, Robert, Kevin and List,

I know what pitch is. That is I know that if I listen to a
single frequency and change ONLY its intensity then the
frequency to which I make the match will change. The change
is well documented in (1) Figure 23 on page 71. Pitch of course is NOT the same as frequency and the relationship between pitch and frequency is again given in (1) page 81 Figure 26. Now comes the most difficult idea to understand. Timber. What is it or what can it be. Pitch of course is measured on a scale of one dimension. What about timber? Certainly a single frequency tone has NO timber. The piano, the violin and drums all have different timbers and these can depend on:

(a) the number of harmonics
(b) the phase of each harmonic relative to a specific harmonic
(c) the intensity of each of the harmonics.

It is thus obvious that timber must be measured along at least the three dimensions I gave above.

Suppose I play the same composite tone but with the amplitude of say the n th harmonic increased by some decibels. Then from Figure 23 we know that the pitch of the n th harmonic will change and therefore so will the pitch of the composite tone. But the envelope of the composite tone will also change because of the change in amplitude of the n th harmonic. If the envelope changes then so must the timber!! If I change the phase relationship of one particular harmonic then the envelope will again change and so will the timber. In fact the three dimensional surface above mentioned is what in part allows us (humans) to distinguish between different musical instruments. As for the number of harmonics it should be obvious that such a change will also effect the envelope. While JND’s for pitch are relatively easy to come by, I would think that one would need at least a Cray Computer to very very slowly develop the 4 dimensional surface representing timber. I have neglected other factor s which would make the required surface have even more dimensions but at least for not the above 3 suffice.

Robert, you said you ran a study with two groups of eight participants. This is a total of at most 16 participants. Later you said that “22/30 of non-musicians failed the training...” Where did the additional 14 participants come from ?

You said that the study was on the effect of timber on pitch perception. This wording to me means that you changed the “timber” and measured the resultant percepted pitch. How did you change the timber. It would seem to me from my ideas above that as timber was changed the expected change in pitch would have to be taken into account.

I certainly would appreciate comments on the above from any and all List members .


References: (1) HEARING: Its Psychology and Physiology Stanley Smith Stevens & Hallowell Davis John Wiley & Sons, 1938 !!

Fred Herzfeld, MIT '54
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Brunswick, Ga.31525