Re: effects of musical experience on pitch perception?

[Fred Herzfeld <herzfeld@xxxxxxxxxxxx>]

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 .

Fred


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

--
Fred Herzfeld, MIT '54
78 Glynn Marsh Drive #59
Brunswick, Ga.31525
USA