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From: shauns@vice.UUCP (Shaun Simpkins)
Newsgroups: net.audio
Subject: Re: CD Reflections-Question, Mr. Simpkins...
Message-ID: <78@vice.UUCP>
Date: Mon, 21-Jan-85 12:45:58 EST
Article-I.D.: vice.78
Posted: Mon Jan 21 12:45:58 1985
Date-Received: Thu, 24-Jan-85 19:37:15 EST
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Reply-To: shauns@vice.UUCP (Shaun Simpkins)
Distribution: net.audio
Organization: Tektronix, Beaverton OR
Lines: 35
Summary: 


Well, Phil said in greater detail than I would what I was going to say about
input filtering, so I won't say it.  However, I can offer some interesting
evidence to his contention that one should just sit back and listen, not worry -
a study has been brought to my attention (I am trying to get a copy of it now)
that examines the psychoacoustic effects of brick-wall filters.  High-order
filters similar to those used in Sony products were cascaded and auditioned.
Two cutoff frequencies were employed - 5KHz and 20KHz.
Result - differences could be heard between the single 5KHz section and a
cascade of 4, while no differences could be heard with the 20KHz cutoff
filters, again in a cascade of 4.  I do not know whether these filters were
compared with Bessel filters of
equal order.  I suspect they were, and will report to the net.  By the way, the
bandwidth shrinkage that you would assume in such an experiment
(final bandwidth = sqrt N where N is the number of identical cascaded stages)
is not correct.  Since these filters' responses aren't Gaussian the shrinkage
is much less.  Therefore, the researchers claim that any audible differences
are primarily caused by phase aberrations.

Whoopee.  Check out the latest issue of TAS.  They auditioned the CD-X1, the
NEC and the KYOCERA player.  RADICAL differences between them.  DISGUSTINGLY
inferior to the digital master tape.

I didn't heard much difference at all when I listened - I might believe that
the CD is less pristine than the master.  I'm still waiting for Rounder Records
to issue their first CD...

The wandering squash,

-- 
				Shaun Simpkins

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