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From: wjm@lcuxc.UUCP (B. Mitchell)
Newsgroups: net.audio
Subject: Re: JSE crossovers
Message-ID: <345@lcuxc.UUCP>
Date: Wed, 17-Apr-85 09:52:38 EST
Article-I.D.: lcuxc.345
Posted: Wed Apr 17 09:52:38 1985
Date-Received: Thu, 18-Apr-85 03:42:27 EST
Organization: Bell Communications Research, Inc.
Lines: 27

JSE developed their "infinite slope" crossover to prevent the same frequency
range from being sent to more than one driver and causing interference between
the signals from multiple drivers.
I have not examined the crossover networks in my JSE-1's (I don't want to void
the lifetime warranty!!) although I strongly suspect that they are passive
L-C-(and probably R) networks.   JSE claims they have a slope of 100 db/octave
which would require a 17th order filter section (and is effectively "infinite
slope").  They have obtained a patent on the circuit, so one might be able
to determine something about the topology from the patent (however, patents are
noted for their vagueness for two reasons - 1) to cover as much ground as
possible and 2) since they are public documents, to give away as little data
as possible, consistent with the legal requirement that "one skilled in the
art" should be able to reproduce the invention from the patent).
What I can say is that the concept works extremely well - I have not heard ANY
speaker costing less than $5000/pair that has better stereo imaging than the
JSE-1 or JSE-2.  Personally, I think the 1's have better midrange imaging
than the 2's but the 2's provide a bit more low bass response (below 35 Hz).
Frequency response on both models is superb.  The 1's list for $925/pair and
the 2's for about $2200/pair.   If you can't afford these two models, JSE
also has a smaller model, the .06 for $545/pair that sounds better than anything
under $1000/pair except its big brother (the 1's).
Admittedly, JSE speakers aren't discounted, but then they are already an
execptional value at their list price.  If you are looking for speakers for
a stereo system with a system price of $1K or more, I strongly recommend you
listen to the appropriate JSE model.
Regards,
Bill Mitchell ({ihnp4!}lcuxc!wjm)