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From: jhenders@wimsey.bc.ca (John Henders)
Newsgroups: rec.audio.high-end
Subject: Re: Subwoofer Building
Message-ID: <11128@uwm.edu>
Date: 18 Apr 91 12:41:06 GMT
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Approved: tjk@csd4.csd.uwm.edu
Originator: tjk@csd4.csd.uwm.edu


	On a different note concerning subwoofers. JBL seems to be useing
something called a triple bandpass design on their newer boxes. Has anyone
seen any articles on the theory behind this? I'd like to see some info on
volume and porting for various drivers.
	The club I work for just put in a pair that have 2 15' drivers
mounted in a centre chamber, magnet to magnet, facing into two other
ported chambers. These boxes are speced to be +/- 3db down to 32hz, and
run at around 90db 1watt/meter. They handle 800 watts and I can attest that
for their size, they are very efficient. 
	I saw the subwoofers JBL is using with their Control series sattallites
recently, and they seem to be using the same design. Anyone have further info,
as our local JBL rep knows less about this stuff than I do?

	John Henders
	Vancouver,B.C.