Subject: Re: Frequency response was Re: [linux-audio-user] Audiophile CD's
From: Jason (hormonex_AT_yankthechain.com)
Date: Sun Jan 27 2002 - 08:33:16 EET
I stand corrected. I knew there was a reason they weren't catching on.
On Sun, 27 Jan 2002, Len Moskowitz wrote:
> SACDs use a variable width pit to prohibit copying, so standard DVD drives
> can't read them.
>
> ----- Original Message -----
> From: "Jason" <hormonex_AT_yankthechain.com>
> To: <linux-audio-user_AT_music.columbia.edu>
> Sent: Sunday, January 27, 2002 12:29 AM
> Subject: Frequency response was Re: [linux-audio-user] Audiophile CD's
>
>
> >
> > > So I have number of questions:
> > > 1) Can regular CD/DVD drives on a PC read them? (If the answer here is
> no
> > > then the rest is irrelevant).
> > 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.
> >
> > > 2) If so, then is there any Linux software to read and play them?
> > no clue. it shouldn't be too hard though, I imagine.
> > > 3) What about writing? (Surprising as it may sound, the regular CD
> format
> > > is actually not quite adequate for fully representing the sound on 78's,
> > > I've even seen signal [and I really do mean SIGNAL not the spectrum of a
> > > click] going up to 29kHz on an _acoustic_ disk [probably a resonance in
> > > the horn]).
> >
> > The human ear can hear fundamentals roughly between 20Hz and 20kHz. It is
> > this poorly understood fact that led to CD's sampling at 44.1kHz.
> > According to the nyquist theorem in order to accurately represent a simple
> > signal
> > digitally, you have to sample it at twice it's own frequency, the result
> > of sampling at less than that frequency is a phenomenon known as Aliasing,
> > in which the samples actually give tehm impression of a mathematically
> > related lower frequency. It actually sounds kind of cool as an effect.
> >
> > So anyway, A/D converters put these brick wall filters in line to
> > eliminate the frquencies above 22.05kHz. Since they have to be cheap in
> > most cases, they start doing that cuttoff a lot sooner. hence why sound
> > blaster and similar sound cards aren't really suitable for quality
> > recordings. cheap card = cheap converters = cheap filters = sound
> > attenuation above 15 kHz.
> >
> > Any way, It's not really fair to compare CD's to vinyls because vinyl
> > doesn't have a flat frequncy response; it's an intentional distortion in
> > order to allow for higher dynamic range. In fact, a lot of the alleged
> > "warmth" of vinyl doesn't come from the vinyl at all, but rather the built
> > in compensation in the phono preamps. That having been said, vinyl is
> > allegedly supposed to be capable of accurate reproduction up to 25kHz,
> > although I don't have the kind of dog ears necessary to be able to comment
> > intelligently on that. However, I defy anyone short of geoff emerick or
> > carl beatty to point me to a sound system that isn't accurately
> > reproducing frequencies above 18k. It's really an issue that too much is
> > made of, IMHO, because most people can't hear it, and of the ones who can,
> > it's such a small portion of the available information, that it's
> > practically irrelevant.
> >
> > What I do know, is that it is possible to hear into a much higher spectrum
> > than 20k when it comes to harmonics, and this is the one argument That I
> > acutally feel is valid when it comes to the dismissal of 44.1 as adequate.
> > Most people who can still hear 20k can distinguish between a 20k sine wave
> > and a 20k square wave. which means that they are at least hearing a few of
> > those overtones that you wouldn't be able to hear as a fundamental.
> > however, I do think that a bit too much has been made of the issue,
> > because as everyone knows, there are only two octaves between 20k and 80
> > k, so there isn't MUCH useful information there, so while 96k recordings
> > do sound nice, I really personally don't feel that it's nice enough to go
> > replacing my CD collection once DVD audio comes down the pike in a big
> > way. Good mixes and good converters mean much more than higher sampling
> > rates.
> >
> > In other words, I wouldn't worry about buring SACD's, and I'd spend my
> > time and money on some really good EQ's, learning the exact implementation
> > of the RIAA reproduce curve in whatever phone preamp you're using,
> > buying fantastic apogee A/D converters and making really good standard
> > CD's. I think you'll find that reduced noise, the more even reproduction,
> > and the flatter response will be much more satisfying sonically that
> > simply upping the sampling rate ante.
> >
> > somebody take away my soapbox, please...
> >
> > ~jason
> >
> >
> > --
> > YankTheChain.com - You can pretend we're not here. That's what I do.
> >
> > ,
> >
>
-- YankTheChain.com - You can pretend we're not here. That's what I do.,
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