Subject: Re: Frequency response was Re: [linux-audio-user] Audiophile CD's
From: Jason (hormonex_AT_yankthechain.com)
Date: Mon Jan 28 2002 - 07:24:12 EET
On Sun, 27 Jan 2002, Remco Poelstra wrote:
> On 2002.01.27 06:29 Jason wrote:
> > DVDROM drives SHOULD be able to read SuperAudioCDs. I say should because
> > I
> > kind of doubt that the ones that exist in the real world actually do.
> > SACD's if memory serves are 20bit 88.2 kHz. Which is inferior to
> > DVDAudio's 24bit96k, so having a DVD laser read them should just be a
> > software issue. I think.
>
> SACD's are 1 bit 2MHz. It's discussable whether they are or are not
> inferior to DVD Audio's. They have a better frequency response and the D/A
> converters are more lineair, but there are great problems with noise
> shaping.
This is correct, to quote sony "Direct Stream Digital (DSD) is a 1-bit
representation of the audio waveform with 2.8224 MHz sampling." It's
pretty
obvious I haven't been doing my homework on
that one; so in the interest of ceasing to speak out of my
gastrointestinal system when backing up my gut instinct that SACD is a
doomed medium, I've done a bit of research and come up with the following
evidence:
<rant>
1.) you can't really compare the rates used for
Pulse Code modulation (CD's and DVD's) to those in Direct Stream Digital.
I really dislike the marketing hype that's going along with the SACD. I've
jsut been doing some reading about this because I don't know as much about
DSD as I should, and Sony's apparently making abig deal out of the alleged
benefit of being able to reproduce frequencies up to 100kHz. Never mind
that they're sampling at nearly 3mHz to do it, and a standard PCM system
could produce a similar freqency response with a sampling rate of ~200k.
Furthermore, several testers have indicated that the extendfrequency
response isn't as clean as the oft quoted 120dB dynamic range would
indicate. this is particularly relevant since the assertion that there is
viable reproducable audio content at those higher frequencies appears a
bit dubious for my previously stated reasons, and if you aren't really
getting a better picture, or more "clarity", and are in fact doing severe
filtering of the upper frequencies, then the argument for all that extra
highfrequncy response disappears altogether.
2.) SACD, much like Betamax, is a propreitary system, whereas DVD-A is
supported by the DVD
consortium. As such, SACD violates Quackenbush's Law, which statess "New
technology will only be adapted by a mass market, if and only if the
developer of the technology makes it easy for Radio Shack to sell cheap
knock offs for cut rate prices". Most DVD players, which have been selling
like hotcakes thanks to judicious understanding of quackenbush's law, will
not play SACDs, and I think it hihgly unlikely that there are enough
buyer's with the type of audio palates that would appreciate the
difference between CD and SACD that are also willing to shell out the cash
for a second high end disc player for a different format, when teh DVD
player they've already bought probably plays DVD-A just fine.
Now, I've never actually heard and SACD, so I could be completely off in
my understanding of the available material regarding it's sound quality.
THis is just my educated guess. However, I doubt that the rank and file
consumer electronics salesman is going to have a very easy time moving
SACD players when compared to DVD players at a similar price point.
Which brings me back to my earlier point, which was, I wouldn't worry
about DVD ROM drives being able to read SACD's.
</Rant>
-- YankTheChain.com - You can pretend we're not here. That's what I do.,
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