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From: rzdz@fluke.UUCP (Rick Chinn)
Newsgroups: net.audio
Subject: Re: Re: CD musings and freqs gt 20 kHz
Message-ID: <520@tpvax.fluke.UUCP>
Date: Thu, 31-Jan-85 04:35:39 EST
Article-I.D.: tpvax.520
Posted: Thu Jan 31 04:35:39 1985
Date-Received: Sat, 2-Feb-85 11:13:22 EST
References: <220@wdl1.UUCP>
Organization: John Fluke Mfg. Co., Inc., Everett, WA
Lines: 27

> 
> RCA used an acoustic low-pass filter with a cutoff of 7Khz.  The
> filter was made of vertically mounted slats which pivoted so that
> the filter could be opened and closed, sort of like a sideways
> mounted Venetian blind.  There was a live instrumental combo behind
> the filter and a curtain in front of it.  Groups touring the RCA
> facility would come into the room, sit down, and do a blind A/B test.

Actually, it was Harry F. Olson, while he was at RCA. The date was circa
1947. You can read more about it in Musical Engineering (now called Music,
Physics and Engineering and reprinted by Dover).

Just a bit of trivia.

Rick Chinn
John Fluke Mfg. Co MS 232E
PO Box C9090 Everett WA 98206

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