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From: sjc@mordor.UUCP (Steve Correll)
Newsgroups: net.audio
Subject: Re: low fidelity CD player?
Message-ID: <3684@mordor.UUCP>
Date: Fri, 27-Sep-85 16:23:32 EDT
Article-I.D.: mordor.3684
Posted: Fri Sep 27 16:23:32 1985
Date-Received: Wed, 2-Oct-85 00:51:50 EDT
References: <470@aero.ARPA>
Distribution: net
Organization: S-1 Project, LLNL
Lines: 29

> .   Meanwhile, the portable [CD player] is analyzed, and the defect found
> .to be a 770 kHz ringing only a few db down from the signal!  No wonder it
> .sounded so terrible, so horrible.  Further tests confirm the worst, and
> .the unit is returned.
> 
> Seriously though...
> 
> This particular unit did exhibit a large 770 kHz component of the signal, as
> well as the 20 kHz ringing we measured (and I HEARD!).  We all agreed that
> the sound was not audiophile quality, although I do not know whether the
> harshness, or "edge", we heard would be a problem in a car stereo or on
> cheap headphones.  I personally could not stand to listen to for very long
> because of the squeal - hissing is far less annoying to me.

Sounds to me like you need to upgrade your system. :-) Your speaker
cables must have excessive IM distortion in order for the 770kHz
component to beat down to a difference frequency within the audible
range. (If your ears really do transduce 770kHz directly, then you must
be in agony, poor soul, whenever an AM radio broadcast impinges on the
filaments of an audiophile-quality tube amp, causing them to vibrate in
sympathy.)

Seriously, quite a few CD players put out a spurious tone at around 24
kHz (I've never seen it reported as low as 20kHz), apparently as a
result of internal clocks beating against each other. Others (notably
the new high-priced Sony full-size players) do not.
-- 
                                                           --Steve Correll
sjc@s1-c.ARPA, ...!decvax!decwrl!mordor!sjc, or ...!ucbvax!dual!mordor!sjc