Re: Fw: sursound: speaker phones (Jens Blauert )

Subject: Re: Fw: sursound: speaker phones
From:    Jens Blauert  <blauert(at)IKA.RUHR-UNI-BOCHUM.DE>
Date:    Thu, 26 Oct 2000 12:14:15 +0200

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(at)UX1.CSO.UIUC.EDU] > Sent: Wednesday, October 25, 2000 20:44 > To: AUDITORY(at)LISTS.MCGILL.CA > 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 >

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