Lossless Files Vs CD's

My understanding is that if a CD is in good physical condition, the main reason why it might sound inferior to playback of a bit-perfect computer file is NOT errors that the player can't correct on the fly in a bit-perfect manner, which would therefore require inexact interpolation. My understanding, based on numerous references I have seen in the past, is that for a disk that is in good condition that will happen rarely during the playing of a disk, and not at all in many or most cases.

The main reason that real-time CD playback may provide inferior results is that electrical noise generated by the servo mechanisms and circuitry in the transport part of the player, as it tracks the disk, may couple into unrelated downstream circuitry in the player, causing jitter in the D/A conversion process, and/or effects on the analog signal path. The degree to which that occurs will be dependent on the design of the particular player, of course, as well as on the condition of the disk.

From this Wikipedia writeup:

Reed–Solomon coding is a key component of the compact disc.... In the CD, two layers of Reed–Solomon coding separated by a 28-way convolutional interleaver yields a scheme called Cross-Interleaved Reed Solomon Coding (CIRC).... The result is a CIRC that can completely correct error bursts up to 4000 bits, or about 2.5 mm on the disc surface. This code is so strong that most CD playback errors are almost certainly caused by tracking errors that cause the laser to jump track, not by uncorrectable error bursts.

Note that the term "error correction," as properly defined in this context, refers to bit-perfect correction. "Error interpolation" is the term used to refer to the less than bit-perfect approximation that can occur (rarely) when bit-perfect correction fails.

And from a post by Kirkus in this Audiogon thread:

CD players, transports, and DACs are a menagerie of true mixed-signal design problems, and there are a lot of different noise sources living in close proximity with suceptible circuit nodes. One oft-overlooked source is crosstalk from the disc servomechanism into other parts of the machine . . . analog circuitry, S/PDIF transmitters, PLL clock, etc., which can be dependent on the condition of the disc.... One would be suprised at some of the nasty things that sometimes come up out of the noise floor when the focus and tracking servos suddenly have to work really hard to read the disc.

Regards,
-- Al

"for a disk that is in good condition that will happen rarely during the playing of a disk, and not at all in many or most cases."

Probably one explanation for why I can't hear a difference in most cases. The eror correction built into CD redbook format is fairly good it seems, but of course there is always a threshold in regards to disk quality and mechanical/optical reader performance/reliability in practice that could make a difference.

It still seems to me that Bit-perfect ripping does provide the best case scenario for reliably getting the data off the optical disk as best as possible still though I would say in that the need to read data in real time with a certain minimum throughput (in lieu of buffering) is a constraint with playing a CD that does not exist with ripping.

THere is still lots that can go wrong downstream from there in regards to jitter in particular even with a practically bit perfect ripped .wav file. More so in general perhaps in the case of FLAC which is lossless but compressed and requires more processing in the D2A conversion process.

Al,

Thank you very much for that post. It escapes attention that a properly designed (with isolation in mind and execution) CDP can sound as good (and sometimes better) as a well set up computer system.

Shiny new object? :-)

As you've stated in many a thread, interaction between components that share close proximity inside a CDP (or DAC, amp, etc.) can and will have a great and deleterious effect on playback if not properly isolated.

There is always a numbers game with any new technology that on paper, sounds great, but in practice, doesn't. Numerous examples abound.

CDPs are a mature and proven product. With careful consideration, one can get a great sounding CDP for under a grand.

Computer audio is in its growing stages. Painful and costly ones at that. One innovation after another is trotted out. Then it's modded. Then the MK II comes out, Then it's modded. Then some overlooked implementation is brought forth. You get the picture.

I hate to bore you all with this as I've stated this already, on other threads, but I can't stress enough, the quality of playback I've gotten from my CDP just by messing around with some cables. CDPs can give you all the satisfaction you need if you just listen.

And as for the argument that one gets about having it all at your fingertips with computer audio and with CDs, you generally limit what you listen to, to about 5% of what you own, I ended up doing the exact same thing with my computer set up as I went for the really good recordings that caught me ears and which I found out, sound much better on my CDP.

All the best,
Nonoise

Jwm - I download all kinds of FLAC files. Then I immediately convert them to .wav. Sounds a LOT better. If you dont hear any difference, its your preamp or your source has jitter too high to hear this. I routinely demonstrate this at RMAF and now at Newport Beach show. Everyone hears the difference.

I know, I know, everyone firmly believes that their system is highly resolving, but get real, it probably isn't. Not unless you have modded every single component including the crossovers in your speakers, used the best cabling and eliminated your active preamp. Then and only then will you maybe be able to easily hear differences in FLAC, .wav and AIFF. I have done all of these.

Steve N.
Empirical Audio

Audioengr,

What is the reason for the sound difference between FLAC and WAV? Is FLAC a more limited format in some way than WAV?

Is it a format related limitation or something more to do with software for creation or the playback?

In my case, 99% of my files are .wav. I have a few FLACS created via different software. I think I hear a difference in general between the two but have not compared carefully enough to say for sure.