Subject: Re: Mel scale, in general From: "James W. Beauchamp" <jwbeauch@xxxxxxxx> Date: Thu, 30 Jul 2009 15:15:55 -0500 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Dick, Don, Leon, Pierre, Richard, Diana, and all, I agree with Leon, that there are two aspects or types of pitch, one associated with "place" and the other associated with periodicity. As long as we can identify the pitch chroma and match the pitch on the piano, we are hearing periodicity pitch. If we sense a general region of pitch, low vs. high, it's place pitch, or tonal height. A nice experiment is to synthesize several harmonics going from k1 to k1 + k2 on a certain fundamental and gradually increase k1 while keeping k2 fixed at say 4 or 5. At what point do we switch from hearing perodicity pitch to place pitch? Another related experiment is start with a fundamental at say 1 KHz and again just have a group of harmonics k1 to k1 + k2. Gradually lower the fundamental while raising k1. I find that my aural receptor goes through some curious gyrations while listening to this sound sequence. I also think Steven's remarks in the book Dick referred us to (Psycho-Physics) to be pretty interesting: "Musicians are often surprised to be told that the apparent size of a fifth expands to sound about seven times larger when it is moved from a low-frequency interval, 64 to 96 hertz, to a higher-frequency interval, 2048 to 3072 hertz. Those intervals both sound like musical fifths -- the frequencies are in the ratio 2 to 3 -- but as Stumpf and other observant and psychologically oriented musicians have noted, a fifth in an upper register seems perceptally larger than a fifth in the lower register. .... The musician's 'equal interval' generally means equal in frequency ratio, and equal frequency ratios do not in general produce equal intervals in subjective pitch." To my ears, bass tones played at various frequencies do kind of compress in that way, but so do frequencies played above 4000 Hz, because it gets to be more difficult to associate a chroma pitch to frequencies in these ranges. Jim Original message: Date: Thu, 30 Jul 2009 20:48:34 +0200 Reply-To: Leon van Noorden <leonvannoorden@xxxxxxxx> Sender: AUDITORY - Research in Auditory Perception <AUDITORY@xxxxxxxx> From: Leon van Noorden <leonvannoorden@xxxxxxxx> Subject: Re: [AUDITORY] Mel scale, in general Comments: To: "Richard F. Lyon" <DickLyon@xxxxxxxx> To: AUDITORY@xxxxxxxx In-Reply-To: <20090730174515.D22D27042@xxxxxxxx> Precedence: list List-Help: <http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>, <mailto:LISTSERV@xxxxxxxx?body=INFO AUDITORY> List-Unsubscribe: <mailto:AUDITORY-unsubscribe-request@xxxxxxxx> List-Subscribe: <mailto:AUDITORY-subscribe-request@xxxxxxxx> List-Owner: <mailto:AUDITORY-request@xxxxxxxx> List-Archive: <http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY> Dick, Your formulation suggests that you identify pitch with chroma. My position is that pitch is a two dimensional entity, in which both chroma and tone height are involved. In a musical context the chroma aspect plays a dominant role. In a speech context I have never noticed the appearance of the chroma aspect. Probably because we never talk with a limited set of fixed pitches. Or because our "vowel processor" is occupied with the meaning of the words and not with the names of the notes, which is certainly the case in the perception of possessors of absolute pitch, who are very chroma oriented. Leon On 30 Jul 2009, at 17:36, Richard F. Lyon wrote: > Pierre, > > I think the resolution is in what Leon said, that the mel scale is > really more about "tone height" or "frequency" than about pitch or > melody. So it's mis-named, at the least. It's also not accurate, > as Don points out, and maybe a cochlear map is really the better > concept. > > But as you also know, it's used in speech primarily because it seems > to work well (at least a local optimum), which is mostly about not > resolving pitch harmonics but adequately resolving formants. I > think you also agree with me in the feeling that it works well > largely because speech systems don't usually have a good model for > what to do with pitch information, so they're better off not > resolving it; and that this is a problem and an opportunity to find > a better way... > > Dick