Subject: Re: harmonic vs. inharmonic sounds (one last time) From: Al Bregman <al.bregman@xxxxxxxx> Date: Thu, 15 Mar 2007 23:11:11 -0500 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Dear Kevin and list, Here's my take on the "perception of the missing fundamental". I'm going to frame it in terms of periodicity because it's easier to explain that way. Whenever a repetitive waveform is played (i.e. one whose partials are all harmonics), we hear the pitch that is characteristic of that repetition rate. For a tone having the partials 200, 300, 400, 500, 600, 700, the same exact waveform repeats 100 times per second. This gives rise to the pitch, "100 Hz RR", i.e., the subjective pitch associated with a 100-Hz repetition rate. Note that a pure tone of 100 Hz also repeats 100 times per second, and therefore, like your complex tone, it has the pitch of 100 Hz RR.. However, it has a different timbre. The repetition rate of the wave determines its pitch but its harmonic structure influences its timbre. Therefore, we shouldn't think of your complex tone as containing a 100-Hz pure tone. It is just that they both have the same pitch. I have framed the explanation in terms of repetition rate because it was easy to do, but it might not be correct. For example a "harmonic sieve" or template, might derive pitch. To be more general, we can say that whatever method is used to compute pitch, the relation between your complex tone and a 100-Hz tone is that they have the same pitch, not that you hear the simpler tone as part of the more complex one.. Cheers, Al ------------------------------------------------------------------- Albert S. Bregman, Emeritus Professor Psychology Department, McGill University 1205 Docteur Penfield Avenue Montreal, QC, Canada H3A 1B1. Tel: (514) 484-2592, (514) 398-6103 Fax: (514) 484-2592 www.psych.mcgill.ca/labs/auditory/Home.html ------------------------------------------------------------------- On 3/15/07, Kevin Austin <kevin.austin@xxxxxxxx> wrote: > On reconsideration, I would reframe the question something as: > > When hearing the partials 200, 300, 400, 500, 600, 700, do you > perceive the fundamental to be 100 Hz? Do you hear a 100 Hz component? > > Best > > Kevin > --