Subject: Re: your mail From: Al Bregman <bregman(at)hebb.psych.mcgill.ca> Date: Wed, 11 Mar 1998 17:46:38 -0500Dear Alexander, Let me reply to your query about anomalies in pitch perception by sandwiching my replies in between parts of your text. I hope you will not mind my sending a copy to the AUDITORY list for comments and to the colleagues that I mention below: According to many music psychologists (Shepard, Krumhansl) there are two aspects to "pitch", namely "pitch height" and "chroma". "Pitch height" refers to the up-down dimension of pitch (e.g., the difference between A440 and A880). "Chroma" refers to the circular dimension, in which pitches repeat again in every octave. I think brightness might be related to pitch height. Galembo: > ... However, the pitch height dimension is not determined well [enough] > to measure it. > The known unit is an octave, but what about fractions of the pitch- > height octave? Bregman: Since pitch height is a psychological property, not a physical one, any measurement would have to come out of a multidimensional scaling. Perhaps the best people to talk to about this would be: Roger Shepard <ROGER(at)PSYCH.STANFORD.EDU>, Carol Krumhansl <clk4(at)cornell.edu> Galembo: > For example, I have a bass A1 tone with eqiual amplitudes and all-sine > phases of 100 harmonics, and another tone having alternate sine-cosine > phases of the odd and even harmonics correspondingly. When dicrectly > compared, the second tone is sounding for some subjects an octave higher > than the first. (This result corresponds, to some extent, to the finding by > Carlyon and Shackleton related to higher unresolvable harmonics of the > middle range fundamentals, published in JASA 95, 3529 (1994)). > But this "A1-A1 octave" interval is not "strong" and might be judged in > other situations as just increased brightness. > If to compare the second ("higher") tone with the real A2 tone, the > interval will also be an octave, but a "stronger" octave, (under "STRONGER" > I mean "more distinctive" in analogy with pitch strength - stronger pitches > have to produce stronger intervals - is it right to say?). > Then the sub-units of the octave in the pitch hight scale have to be > the units of the "octave strength"? But what then to do with this "octave > strength" if the phases manippulation make pitch of the tone becoming > distinctive fifth of the fundamental? > If I am understandable here, I would like to know your opinion. > Bregman: I have often thought that the pitch height dimension could separate two C's (for example) by more or by less than a conventional "octave, depending on the spectrum of the tones. Musicians might not like this, but it seems to agree with many phenomenological descriptions like yours. Perhaps we should argue as follows: The octave is a musical concept, not a perceptual one. We assume that an octave is defined by two tones that have the same chroma, but different pitch heights. Typically, when the spectra are similar (whatever that means), a 2:1 ratio of fundamental frequencies gives rise to the difference in pitch height that we associate with an octave. In such cases, (e.g., comparing notes on the same instrument), we don't notice the contribution of the spectrum to pitch height. I think many people have noticed the difficulty with the identification of a given fundamental with a definite pitch height, among them John Pierce at CCRMA. - Al ---------------------------------------------------------------------- Albert S. Bregman, Professor, Dept of Psychology, McGill University 1205 Docteur Penfield Avenue, Montreal, Quebec, Canada H3A 1B1. Phone: +1 514-398-6103 Fax: -4896 Email: bregman(at)hebb.psych.mcgill.ca Lab Web Page: http://www.psych.mcgill.ca/labs/auditory/laboratory.html ---------------------------------------------------------------------- > > Alexander Galembo, Ph. D. > NSERC-NATO Science fellow > Acoustics lab, Dept. of Psychology, Queen's University > Kingston ON K7L3N6 > Canada > > Tel. (613) 5456000, ext. 5754 > Fax (613) 5452499 > E-mail: galembo(at)pavlov.psyc.queensu.ca > URL : http://www.geocities.com/CapeCanaveral/Lab/8779/