I just want to summarise this thread.
It seems to me that it is very likely that if CDs are ripped to Flac using
Exact Audio Copy in sercure mode and a good DAC is added to the digital
output of the Squeezebox then there is no real reason why the analogue signl
to a hifi amp should not be more accurate than that obtained from a very
expensive CD Player.

Hmmm... better sell my CD player quick....

Simon Turner
Brighton UK

-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com]On Behalf Of Pat Farrell
Sent: 27 February 2004 02:11
To: Slim Devices Discussion
Subject: [slim] [OT] Audiophiles: Can the audio reproduction of the CD
be equalled or bettered?


At 05:11 PM 2/26/2004, Mark Bennett wrote:

Pat Farrell wrote:

The beauty of digital audio is that it is digital, it flat works or
does not.
No room for subtle degradations.
I'm not so sure I agree with this statement in this context.
In absolute terms you're completely right, but this is different.

No, it really isn't. :-)
Actually I think we are in agreement here.


The problem with CD player's is that they do occasionally read
the disc wrongly, and when the error correction is overloaded
they send out bad information. This damages the works/doesn't
work argument, because a few bits here and there wrong in the
data stream, which the mechanism interpolates to fill in for,
would be very hard, if not impossible, to detect subjectively.
As a whole I would expect them to appear as a subtle degradation.

Correct. Since Red Book audio is read as analog pits, there is
plenty of room for the reading/extracting process to go wrong.
And the specs have assorted error correction techniques, and
finally some "fake the last signal" stuff to avoid silence.

And PC readers vary in quality a lot. The cheap ones do not
extract reliably. I use the TDK Velo ones, which are more expensive
but a lot more accurate. It is next to impossible to find out what
the real error rate is, some of the errors are caught and fixed in
the drive circuitry before it gets out to any real part of the CD player.
The errors have to be pretty massive before the main player
error fixup routines are called.

It might be cheaper to buy new CDs for the few that won't read
than to worry about it.


I suspect that in most cases the uncorrected error rate is pretty
low, if not zero, but I wouldn't like to put money on it.

It can be very high. Depends on the CD drive, the media,
surface grease, dirt, etc. It is common for two drives to extract
different files from a single CD.


The squeezebox really should have zero errors all the time, since
hard disks and computer networks have so much error correction
built in that it isn't likely to happen. If you get glitches on
the squeezebox it's probably going to be because the buffer empties
than any other reason.

Again, this is really a separate issue.
Once the data is properly extracted ("ripped") then
you can transfer it all you want. The Sqbx will only
glitch if it is not fed fast enough.

A suitable network should more than keep an DAC happy.
And if not, you can replace hubs with switches, which are nearly
as cheap. Red Book audio only needs 150kB/s. Which is trivial
on any decent network. Even 96/24 stereo only needs about
four times that, still trivial.

Pat