From: mbk@lyapunov.ucsd.edu (Matt Kennel)
Newsgroups: rec.audio
Subject: Re: New LP-CD flame material
Date: 7 Apr 92 16:33:15 GMT
Organization: University of California, San Diego
NNTP-Posting-Host: lyapunov.ucsd.edu

jgardner@convex.com (John B. Gardner) writes:
: {DCC vs. straight wire subjective test gives null result}
: In article <ku1ib2INN2kp@network.ucsd.edu> mbk@lyapunov.ucsd.edu (Matt Kennel) writes:
: >I bet that if the same test were done, but with standard CD technology A/D 
: >and D/A vs. straight wire, one would get the same null result.
: 
: Strawman!  Strawman!  :-)
: 
: >And yet, how do CD players sound different if digital sounds like nothing?

: First, you'd lose the above bet.  Unequivocal ABX tests have shown CD players 
: can and do sound different, most notably the 1st generation with brick wall 
: filters and poor D/A's vs. the current 1 bit (bitstream) technology.

Oh yes, I believe that.  Real live "CD players".  What I'm trying to say is
that perhaps the quality of the components used in scientific listening
tests, say if we challenged Philips research labs {or whoever also makes
DCC} to put together a setup, is significantly better than those that come
out in consumer form.

: Second, CD and DCC technology are worlds apart.  Did you know that DCC 
: actually has (variable) 18 bit resolution?

Great.   But if everyone records with 16-bit linear no compression, this
doesn't really help, does it?

: It most certainly affects the 
: data recorded in a major way, such that it would be a poor choice for 
: archival purposes, but hey - the report said despite the modulation of the 
: noise floor and variable quantitization, the process on 1st generation
: processsing was inaudiable - which is significant.

Is it idempotent? I.e. a snotty way of saying, if you take a compressed
signal, uncompress, and re-record will you get the exact same compressed
signal, or with there be further degradation? 

Without any evidence, I suspect it isn't.  Perhaps at the pressure of
the recording industry....  \begin{paranoia}
"Sure copy all you want---yes it's digital! perfect forever, 
but wow doesn't that weird scratchy sound get alot worse the more
you copy it?  Oh sorry, no digital out or in, uh, we can't make it work
with the standard protocol, yeah that's the ticket..."

: Maybe, but one could argue that the *engineered* performance differences
: between the CD players of 5 years ago and today are audiable.

Maybe I should get a new player. I have an old Pioneer, probably 2nd
generation if not first.  (I.e. no mention of oversampling on the
marketdroidglitzyletteringonfrontpanel.)  I've compared it to my fairly
recent Sony D-66 portable "8x oversampling dual D/A converter...blah blah).  The
difference is extremely small. (I'm listening to mostly classical on
magnaplanar speakers) Will there be a much bigger difference comparing with
a modern home unit?

: Certainly
: the differences between "middle ground" players now are much smaller than 
: in the past, if due to nothing else than not relying on ultra-percison D/A's
: thanks to 1 bit technology.

So just about any of them would do OK?

:    /\ /_  _    jgardner@convex.com


Matt Kennel
mbK@inls1.ucsd.edu
From: kurts@hpnmdla.sr.hp.com (Kurt Strain)
Date: Thu, 9 Apr 1992 15:33:51 GMT
Subject: Re: Re: CD rot -- who gives a damn?
Organization: Milky Way Galaxy