Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/3/84; site teddy.UUCP Path: utzoo!decvax!decwrl!Glacier!oliveb!hplabs!hao!seismo!harvard!talcott!panda!teddy!rdp From: rdp@teddy.UUCP Newsgroups: net.audio Subject: Re: Print-thru: Magnetic or Mechanical Message-ID: <1623@teddy.UUCP> Date: Mon, 11-Nov-85 11:07:38 EST Article-I.D.: teddy.1623 Posted: Mon Nov 11 11:07:38 1985 Date-Received: Thu, 14-Nov-85 18:42:59 EST References: <937@cvl.UUCP> <2860@wateng.UUCP> Reply-To: rdp@teddy.UUCP (Richard D. Pierce) Distribution: na Organization: GenRad, Inc., Concord, Mass. Lines: 29 In article <2860@wateng.UUCP> gtward@wateng.UUCP (Greg Ward) writes: >> If it is a mechanical phenomenon, then it should be stronger in one >> channel (the channel etched on the side adjoining the next groove) than >> the other. The record should also be in the same orientation at the >> onset of the pre-echo and at the onset of the corresponding music. >> Since I don't have any records with noticeable print-thru, I'd be interested >> to hear if other people's print-thru satifies/doesn't satisfy these >> conditions. >> >> - John Canning (jc@cvl.umd.edu.arpa) > >Your argument for why mechanical print through would be stronger on one >channel then the other is incorrect. You seem to be suggesting that each >channel is recorded on a different side of the groove. In fact, how the >two channels are multiplexed in the groove is that one channel is >recorded in the side to side variations of the groove, and the other is >recorded in the up and down variations. > > - Greg Ward Not entirely correct. In fact, the vertical modulation constitutes the L-R signal, while the horizontal modulation constitutes L+R. When we get all done figuring out how this mish-mash works, then we find that indeed, one wall holds the right channel information, and the other wall the left channel. The two channels are "out of phase" with one another so that the rumble components (thought to be primarily vertical motions) are playeed back out-of-phase. For all intents and purposes, each wall holds one channel worth of information.