Re: Fw: sursound: speaker phones ("Beerends, J.G." )

Subject: Re: Fw: sursound: speaker phones
From:    "Beerends, J.G."  <J.G.Beerends(at)KPN.COM>
Date:    Thu, 26 Oct 2000 10:44:40 +0100

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

This message came from the mail archive
maintained by:
DAn Ellis <>
Electrical Engineering Dept., Columbia University