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Re: Is there considerable phase locking up to 6 kHz?

chen-gia tsai wrote:

Dear all,

I am working on the pitch perception of music sounds with dominant upper odd-numbered harmonics.

... snip...

This finding prompts the question: is there considerable phase locking up to 6 kHz?

Hi Cheng-Gia,
to the best of my knowledge, the answer to your prompted question is that, unless you are a barn owl (who may phase lock up to 9 kHz), the answer is almost certainly no. Auditory nerve recordings in cat and guinea pig have shown rather similar roll-offs in phase locking, starting at about 2 kHz or so (the curve rolls off earlier in guinea pigs) and by 4kHz there is practically no phase locking left. I don't know of any data from human auditory nerve fibres (for obvious reasons, such data would be hard to come by) but I think most auditory physiologists would be very surprised if any mammal was found to phase lock appreciably to frequencies above 4 kHz. Non-mammals typically do much worse than mammals. In this respect (as in many others) barn owls seem to be extremely unusual, and they should perhaps be reclassified as aliens from outer space.
When you mention that your stimuli lead to a perception of a rising "melody", you may have to tread a little carefully. When you say, "the musical pitch is ambiguous", some might argue that "ambiguous" means there no longer is "pitch" in the strict sense, and hence there is no longer "true melody". This isn't really my field of expertise, but I believe that frequency discrimination limens get much larger for frequencies above 4 kHz. If listeners can no longer easily discriminate a semitone, are we still looking at pitch phenomena?



Dr. Jan Schnupp
University Laboratory of Physiology             St Peter's College
Oxford University                               New Inn Hall Street
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