Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site opus.UUCP
Path: utzoo!watmath!clyde!floyd!harpo!seismo!ut-sally!opus!rcd
From: rcd@opus.UUCP
Newsgroups: net.audio
Subject: (more on passive speakers, etc.)
Message-ID: <235@opus.UUCP>
Date: Thu, 15-Mar-84 20:12:01 EST
Article-I.D.: opus.235
Posted: Thu Mar 15 20:12:01 1984
Date-Received: Fri, 16-Mar-84 07:41:40 EST
References: <1049@inmet.UUCP>
Organization: NBI, Boulder
Lines: 21

> > 2.  Extra speaker in addition to the normal stereo pair...
> This isn't quite as far-fetched as it sounds.  THE AUDIO AMATEUR ran an
> article a few years back entitled "The Not-Quite Passive Radiator".  The
> premise of this article (sorry, I no longer have it) was basically:  When
> using a conventional woofer as a passive radiator, an R-L-C network could
> be attached to it to 'tune' its response by reinforcing the voice coil...

This misses what people have been questioning.  A passive radiator is built
into the same cabinet as the active radiator it supports - and is typically
not less than about 2/3 the area of the active radiator.  By being in the
same enclosure, the displacement of the passive radiator cone can be
expected to be on the same order of magnitude as that of the active
radiator - as compared to having a speaker "out in the room" where the
phonon field is much diminished.

Incidentally, the electrical tuning of the passive radiator is one way to
twiddle (sorry about the technical term :-) its effect - it can also be
tuned mechanically by placement, baffles, etc.
-- 
Cerebus for Dictator!
{hao,ucbvax,allegra}!nbires!rcd