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Re: Fw: sursound: speaker phones

There is no such thing as a "law of the first wavefront" for timbre.
Timbre is determined by the incoming energy over up to 100 ms - like loudness.
So, something must be wrong with the statement below.

Jeens Blauert

> The answer is binaural and monaural decolorization, the first wavefront
> determines the timbre. With recordings the correct binaural and monaural
> cues are missing and thus its sounds hollow/colored. A ref. for the binaural
> decolorization:
> P. M. Zurek, "Measurements of Binaural Echo Suppression", J. Acoust. Soc.
> Am., vol. 66, pp. 1750-1757 (1979 Dec.).
> John Beerends
> KPN Research
> -----Original Message-----
> From: James W. Beauchamp [mailto:j-beauch@UX1.CSO.UIUC.EDU]
> Sent: Wednesday, October 25, 2000 20:44
> Subject: Re: Fw: sursound: speaker phones
> While we're on the subject of sound localization, can someone explain
> why speaker phones always sound like you're "talking through a tube" to
> the person on the other end of the line? I'm radiating a sound which
> is picked up by a diaphragm on a table and then directly transmitted
> to someone's ear via a small speaker. How is this substantially
> different from my talking to a hole in the table with someone's ear
> directly underneath?
> Here is a related problem: Suppose I wish to record someone talking in
> the front of the room, and I am in the back of the room. When I am
> actually there listening, the speech is as clear as a bell; I ignore
> all environmental sounds and echoes. To (roughly) simulate the pressures
> at the ears, I take the headphone of my Walkman, put it on, and use it
> as a stereo microphone. Later, when I play it back through the headphones,
> the basic sound is there, but now the echos and environmental sounds swamp
> out the speaker, who is rendered barely audible. Does using really good
> mics help? (Cheap actual mics don't seem to improve the situation.)
> If we understand what the problem is, how do we correct for it?  E. g.,
> why aren't there better speaker phones? (Maybe there are for a price.)
> I realize that this problem is being worked on in the context of hearing
> aids -- my neighbor has to take his off in order to hear a conversation
> when there's more than 1 other person talking -- and in tele-conferencing
> applications.
> Jim Beauchamp
> Univ. of Ill. U-C