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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
(1) HEARING: Its Psychology and Physiology
Stanley Smith Stevens & Hallowell Davis
John Wiley & Sons, 1938 !!
Fred Herzfeld, MIT '54
78 Glynn Marsh Drive #59