| Dick,
Reading your very thoughtful analyis the real, I mean “real,” question that comes to mind is what, if any, the use of the many available HRTF databases is, since (as you state) these functions are time varying and even subject to cognitvely induced changes. This being the case, the only reliable HRTFs are those measured in KEMAR, a head the cognitive functions inside which should be negligible.
Pierre Sent from my iPad Hello Mr. Schoenwiesner -
Here are the mails that have come to me. As Dorte Hammershoei rightly notes, the outer ear transmission functions are old hat. In particular, Shaw has contributed much to this. The word "head-related" has long been common and semantically correct in stereophony as opposed to "spatially referenced". The transfer function to the eardrum from a plane wave or the near field of a source are not head related, but are just the transfer functions of the head (together with the upper body). At the time, Geo Plenge had a big problem with Dennis McFadden, who did not want to print his article on Out-of-the-Head Locality. I always suspect nor that Dennis suggested the wrong term HRTf, instead of HTF, which would have been better. Now, the abbreviation HRTF but has introduced worldwide, and especially Americans love handy shortcuts. More interesting today is the question to what extent HRTFs, which presuppose LTI systems, describe the situation with sufficient accuracy. For example, the eardrum impedance is modulation-dependent. This is but u.a. controlled by the middle ear muscle reflex, where even cognitive feedback plays a role. Furthermore, head movements play a major role in current research, with the "HRTFs" being time-varying !! So there is still much to do. I myself have the pure discovers physical aspects of this topic and is currently writing. about feedback in the auditory system.
- With kind regards, Jens Blauert
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