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From: tommie@psivax.UUCP (Tom Levin)
Newsgroups: net.auto.tech
Subject: Re: Summary: Car speaker problem
Message-ID: <1049@psivax.UUCP>
Date: Wed, 5-Mar-86 16:06:07 EST
Article-I.D.: psivax.1049
Posted: Wed Mar  5 16:06:07 1986
Date-Received: Sat, 8-Mar-86 02:32:37 EST
References: <2003@uwmacc.UUCP>
Reply-To: tommie@psivax.UUCP (Tom Levin)
Distribution: net
Organization: Pacesetter Systems Inc., Sylmar, CA
Lines: 39
Keywords: Polypropelyne speakers, paper speakers

In article <2003@uwmacc.UUCP> jwp@uwmacc.UUCP (Jeffrey W Percival) writes:
>Problem: Car speaker (Pioneer ts-411) had a raspy noise, correlated
>with bass notes.
>
>Possibilities:
>4. Warped cone, rubbing on the piston.
>   Bingo.  The cone material is a paper-like substance, and
>   moisture from the trunk area plays havoc with speaker cones.
>
>There's no fixing this problem, so I'm shopping for new speakers.
>Some people recommended speakers with polypropylene cones.  A
>membranous material that looks highly resistant to moisture.
>All the good manufacturers make some models with this material,
>and I think I'll go with that to avoid buying speakers every
>two years.

Indeed, polypropylene is water proof as well as temperature proof.
Thus, it is an ideal material for a car speaker.  

There is an alternative, though.  For those of you who have paper
speakers, why not make them water resistant by treating them?
Go to your nearest art supply store and buy a small bottle of 
"Acrylic Mat Medium" along with a small paintbrush.  Apply a THIN 
coat (you don't want to change the speaker's mass significantly) 
to the speaker.  Not only will this make it water proof, but it will 
also "clean up" the mid-range quite a bit!  This is an old trick in
the speaker biz to make cheap drivers sound better.  It works because
you "stiffen-up" the driver without adding much to it's mass.  Are
you skeptical?  Well, Polk audio does this with their loudspeakers.
They buy cheap paper drivers and then treat them with "plastiflex".
I have used Acrylic Mat Medium on more than one system I've built
(both home and audio) with excellent results.

Cheers!
-- 
__________________________________________________________________________
Tom Levin           {ttidca|sdcrdcf|logico|scgvaxd|bellcore}!psivax!tommie

"Turn it up!!!"