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Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!charm!prk
From: prk@charm.UUCP (Paul Kolodner)
Newsgroups: net.audio
Subject: Turntable-platter resonances
Message-ID: <682@charm.UUCP>
Date: Tue, 11-Jun-85 20:32:36 EDT
Article-I.D.: charm.682
Posted: Tue Jun 11 20:32:36 1985
Date-Received: Wed, 12-Jun-85 20:20:40 EDT
Organization: Physics Research @ AT&T Bell Labs Murray Hill NJ
Lines: 10

Ahem.  I have a question.  Every now and then (as recently
on this net), I see comments about turntable mats and 
record clamps.  These seem like a fine idea, but I don't
understand why people talk about resonances in the same 
connection.  The air space underneath a record has a thickness
of a millimeter or less, putting its resonance frequency
way above the audio range.  Vibrations of the record might be
resonant, but the speed of sound in vinyl is so much higher
than in air that the resonance frequency ought to be real high
there, too.  So, I'm a bit confused.  Any comments?