Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uwm.edu!csd4.csd.uwm.edu!info-high-audio-request
From: kasha@twolf.ce.YALE.EDU (Dan B. Kasha)
Newsgroups: rec.audio.high-end
Subject: Re: Crossover Passion.
Message-ID: <13499@uwm.edu>
Date: 27 Jun 91 12:54:35 GMT
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Approved: tjk@csd4.csd.uwm.edu
Originator: tjk@csd4.csd.uwm.edu

I wish to answer the first part of your question.  You say low
frequencies are dispersive.  Not true.  As you know, Radio Frequencies
can be beamed to sattlites by antenna arrays.  I remeber a trick
question in a physics of music class.  "What is larger, a woofer
or a tweeter?"  The trick was that they ment larger compared to
the wavelength, which is the naswer to your question.  A woofer
diam. is about a foot.  And at 20 hz, the wavelength is many feet
(look at a low organ pipe).  And the woofer diameter is very small
compared to wavelength.  At 1KHz, the wavelength is about a foot.
When the wavelength is large compared to the source, the sound is
omni directional.  When the wavelength is cmparable or smaller than
the source, the sound is directional.  This is why I hate 2 way
speakers.  The woofer must go to a couple of KHz, and if it is
large enough to have guts, it has no dispersion.  I do not sit in
an ideal spot, and I like a reflective sound, so I like when the
1KHz stuff bounces off the walls.  At 20Khz, the wavelength is
about 1/2 inch.  The tweeter beems then as well, but there is little
to do about that.  I like multi tweeter/mid speakers that shoot
sound all over. I do not buy the interference stuff, and have heard
such speakers DUST the best- B&W, Magnapan's, Duntec, though the
speaker is a bear to work with.  The Cello speaker - based on the
1968 AR LST!