Subject: Re: Robust method of fundamental frequency estimation. From: Eckard Blumschein <Eckard.Blumschein@xxxxxxxx> Date: Thu, 1 Mar 2007 12:41:20 +0100 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Richard F. Lyon <DickLyon@xxxxxxxx> wrote: > I assume you mean C. Kaernbach and L. Demany: "Psychophysical > evidence against the autocorrelation theory of auditory temporal > processing". Yes. >> ... I do not expect a simple mathematical solution at all, because the >> multipolars within CN do not synchronously respond to the >> frequency which stimulated the IHCs. Neurons are generally too slow as to >> directly convey all audible frequencies. Chopper frequencies in the kHz >> range are impossible due to refractory time. So auditory nerve and cochlear >> nucleus perform something like down-sampling. So harmony and in particular >> octave unison are quite natural phenomena. We need not look for their >> 'learned' basis. > > Here I have no idea what you think you're responding to. To some extent I tried to temper my own ideas http://iesk.et.uni-magdeburg.de/~blumsche/M277.html to some extent I uttered an anticipatory antithesis to what meanwhile Martin Braun and others contributed to this discussion. I am well aware of e.g. Edward W. Large of Florida Atlantic University who explains pitch like the result of a comparison between an expected cortical pattern of excitation and 'phase' of stimulus. Do not worry about the seeming contradiction between his complex Hopf oscillator and my insight that we do not need phase of a single signal, so called linear phase, at all. Relative phase is an apt parameter in case of comparison between different signals. One may benefit from using complex calculus but beware of misinterpreting complex results, cf. http://iesk.et.uni-magdeburg.de/~blumsche/M283.html. Acknowledging the role of comparison between upward input and active downward expectation which is also evident in vision, we should nonetheless not ignore that down-sampling of frequency is a must in mammal audition, and it necessarily goes along with something similar to a neural second analysis of an already mechanically cosine transformed signal. Therefore, I do not see any alternative to unlearned basic octave unison. I do dot accept the argument that octave unison must be explained by circular chroma attributed to thalamus rather than small integer periodicity just because generalisation over the distance of two octaves was found to be even stronger than that over the distance of one octave. We should have learned from the quarrel between Ohm and Seebeck that neural systems can easily be misinterpreted. What about the neural mechanisms, I guess we will understand them best if we imagine evolution like a player who tries to apply, modify, and judge every new occasionally found principle as universal as possible. Eckard