Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site moncol.UUCP Path: utzoo!dciem!nrcaero!pesnta!moncol!ben From: ben@moncol.UUCP (Bennett Broder) Newsgroups: net.audio Subject: Re: If I may step aside from the CD/LP Wars,... Message-ID: <369@moncol.UUCP> Date: Sat, 8-Jun-85 13:25:29 EDT Article-I.D.: moncol.369 Posted: Sat Jun 8 13:25:29 1985 Date-Received: Mon, 10-Jun-85 01:09:51 EDT References: <2412@decwrl.UUCP> <350@moncol.UUCP> <304@tilt.FUN> <1199@hound.UUCP> <164@harvard.ARPA>, <1210@hounRe: If I may step aside fromSat, 8-Jun-85 13:25:29 EDT Organization: Monmouth College, West Long Branch, NJ 07764 Lines: 69 No, the benefit of the record clamp is not imaginary, it is one of the reasons that Oracle and Sota vacuum turntables sound so good. There are 4 reasons that record clamps work: -- 1) Vinyl resonances As the stylus accelerates laterally and vertically to follow the groove undulations, forces are generated on the order of 1000 g. All materials have inherent resonances that can be excited if enough energy is applied to them, and vinyl is actually quite a "lively" material in this sense. Some of the brittle harshness heard in modern music systems is actually a result of the stylus reading these mechanical vinyl resonances, which have been excited by the stylus itself. 2) Vinyl as an Energy Storage Medium Vinyl is an elastic material (i.e. "springy") This means that energy that is fed into it is actually absorbed for a certain length of time (like a spring compressing) and then released over a certain length of time (like a spring expanding). The drawbacks are as follows: as the stylus plays a transient it generates a shock wave into the disc. You hear the transient and then you hear it echoing back as the vinyl releases the stored shock wave over time. The major audible effect is a general blurring and smearing of musical detail, since this process is going on throughout the entire duration of the playing record. 3) Vinyl as a Transmitter of Acoustic Energy Acoustic energy in the air is reflected by or stored in the vinyl, and is retransmitted back to the stylus as unwanted vibration. Result: further blurring of detail, usually accompanied by boominess in the bass. 4) Warps This is one we are all familiar with, and is again due to the elasticity of vinyl. Warps upset the stability of the entire playing system, actually cause a change in the pitch of the music in the groove that the warp deforms (warp wow) and in general create severe subsonic problems throughout the entire reproduction chain. A warp also results in a portion of the record being suspended in free air, which increases dramaticlly its susceptibility to all kinds of excitation. -- The above, excerpted from an Oracle white paper, is given in support of their record coupling system, consisting of a special turntable mat, a screw on record clamp, and a little spacer which raises the record slightly in the label area. I would highly recommend purchasing the Oracle Groove Isolator mat and an appropriate record clamp. The Oracle mat is completely flat (sculpted ridges create air pockets under the record that resonate), and made of a special damping plastic absorbs vibration before it can be retransmitted to the stylus. Try tapping the runout groove with a pen and you will see what I mean. On a normal mat the sound is a high pitched 'tick', on a record clamped to the Oracle mat, a dull, barely audible thud. I think you will find that using a record clamp in conjunction with this mat will yield improvements far more noticable than using the clamp alone. Ben Broder ..ihnp4!princeton!moncol!ben ..vax135!petsd!moncol!ben