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From: bhs@siemens.UUCP
Newsgroups: net.audio
Subject: Re: Request for Opinion (Golden Ears) Re
Message-ID: <30200002@siemens.UUCP>
Date: Tue, 19-Mar-85 09:09:00 EST
Article-I.D.: siemens.30200002
Posted: Tue Mar 19 09:09:00 1985
Date-Received: Thu, 21-Mar-85 02:47:16 EST
References: <1007@hound.UUCP>
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Nf-ID: #R:hound:-100700:siemens:30200002:000:2872
Nf-From: siemens!bhs    Mar 19 09:09:00 1985



Well, here we go again...

Categorically, the oversampling technique is superior to brickwall, analog
filters. However, the question of wether one can hear any difference is not
answered as easily as that. One componenet frequently introduced by the analog
filters is ringing, which is caused by the capacitors used. Another is the
phase shift which you mentioned. 
The digital filtering used with quadruple oversampling does not introduce any
frequency dependent phase shift. It also severely reduces ringing. It can not
entirely eliminate it, as there is still an analog filter in the system, in
order to filter out the high-frequency switching transients from the D-A
converter.
What is most critical in the analog filters is how meticulous the filters have
been designed- leafing through a very technical report on various CD players
available on the German market, it was quite revealing to see the differences
in output code coming from the various analog filters used in the various
players. Comparing even the best of the analog filters with an oversampling
machine showed quite clearly the advantage of the digital filters. 

But, I notice that I have not yet answered your question. I believe that you
can hear a difference between a player incorporating oversampling and one with
analog filters. Analog filters tend to create a sound which is slightly
crisper, sometimes harsher and colder, than that put out from digital filters.
I atribute this to the relative lack of high-frequency ringing. This feeling is
confirmed by my observations comparing my Magnavox 2020 with my brother's
Technics SL-P8. Mine is more mellow, without sacrificing any of the clarity or
high-end sound. Ah, well, this is of course a matter of taste.
An additional caveat- I do not think that, after listening to several players,
you would definitively be able to state which ones had analog filters and which
ones had oversampling. You are not comparing Chevettes to Corvettes. However,
you are comparing slightly better machines with slightly-less-better machines.

Oh, and I do not see why going for oversampling will kill your budget. The
people who built the first oversampling CD player also are quite inexpensive.
Philips and Sony co-developed the standard. Sony concentrated on building a
machine with fancy remote control and good programmability, while Philips sat
down and designed the better signal processing- quadruple oversampling, digital
filtering. Somehow, I bought my player for it's sound, not for it's
programmability. I have a VAX at work for that. And- it cost me $299. The newer
Magnavox players have remote control and improved programmabiltity, but I give
mine the edge in styling. Oh, an added bonus- what is sold here as the Magnavox
player is identical to the Philips players- they are all built in Belgium.

Bernard H. Schwab 
Siemens RTL, Princeton NJ