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Re: About importance of "phase" in sound recognition.

Hello Emad,

this is a very late reaction (I have been in Canada), and it is not an answer to your question (I am unfamiliar with implants). I hope, however, that I may have something relevant to say about the influence of phase on timbre. The finding of Plomp and Steeneken ["Effect of Phase on the Timbre of Complex Tones", JASA 46 (1969) 409-421], that the effect is noticeable at low frequency, may be due to the fact that the strong-vibration zones of the BM due to sine tones of frequencies f and 2f overlap if f is low. I just did an experiment on the DX11 music synthesizer with f = 55 Hz and 2f = 110 Hz. The wave form depends on the delay between the two sine tones, and that delay varies accidentally from one try to the next. Indeed there are slight differences. In some tries the sound is smoother than in other tries. At 55Hz and 110 Hz, there are inner hair cells the motion of which is a superposition of 55 Hz and 110 Hz, and the moments of time of the nerve potential spikes from these hair cells depends on the wave form. For choir and orchestra music it is relevant that the just mentioned sound variation is slight.

----Ursprüngliche Nachricht----
Von: emad.burke@xxxxxxxxx
Datum: 13.10.2010 17:09
An: <AUDITORY@xxxxxxxxxxxxxxx>
Betreff: Re: About importance of "phase" in sound recognition

I just had one question about Roy's last email, which is a intriguing question that i has been puzzling me for quite a long time, and shortly that is : if the cochlear (mechanics) effects on the perception of sound are that crucial as a lot of people in the cochlear modeling community also stress on, then how would you explain the hearing capabilities of the "deaf-born" patients with the help of cochlear implants that use quite a crude representation of auditory nerve spikes at least compared to super complex structures that has been developed in the cochlea over the ages. Actually there are various cases that shows after a period of learning, these people can earn a remarkably significant hearing sense. is there any explanation for this in your theorem of hearing ? 


Reinhart Frosch,
Dr. phil. nat.,
CH-5200 Brugg.
reinifrosch@xxxxxxxxxx .