Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site brl-tgr.ARPA
Path: utzoo!watmath!clyde!burl!mgnetp!ihnp4!houxm!houxz!vax135!floyd!cmcl2!seismo!brl-tgr!mike
From: mike@brl-tgr.ARPA (Michael John Muuss )
Newsgroups: net.audio
Subject: Re: CDs don't you just love them??
Message-ID: <3051@brl-tgr.ARPA>
Date: Sun, 17-Jun-84 17:09:32 EDT
Article-I.D.: brl-tgr.3051
Posted: Sun Jun 17 17:09:32 1984
Date-Received: Fri, 22-Jun-84 08:45:58 EDT
References: <4@sunybcs.UUCP>
Organization: Ballistics Research Lab
Lines: 29

Charles Pearson asserts 
 
	If they are sooooo good, them how come they naver can produce a 
	square square wave?

My NEC 803 produces a marvelous square wave.  While 44.1 khz is
woefully inadequate in my opinion, the NEC's technique of replicating the
samples and then dong digital filtering, and running the DACs at a much
higher rate with the (digitally) filtered result avoids all of the high
frequency problems that most CD players are guilty of.  The Philips
machine uses this technique too, although I have heard tht they had to use
14 bit DACs instead of 16 due to the higher data rates needed...

It is difficult to see how a test disk written by computer is likely to 
NOT have a perfect square wave on it -- my test CD does.

As for the validity of testing auudio equipment with 20 khzsquare waves,
Charles is RIGHT ON.  *I* can hear the difference between a 20 Khz
square wave, and a 20 Khz sine wave.  The only difference is due to sine
wave components at frequencies > 20 Khz.  Therefore, extended frequency
range is VITAL to accurate reproduction of very high frequency sounds,
esp. percussion.  This includes having speakers that are capable of
reproducing the high frequencies, too.  (My Infinity Quantum-2's are
flat to 30 Khz, and gradually roll off beyond that.  My Kenwood High Speed
amp is flat to > 100 Khz.  Even my Ortofon MC-20FL cartridge is fairly flat
to about 25 Khz.)

-Mike Muuss