Why does the quality of a cd player matter for playback but not for ripping?

[zenpmd]

Thanks!

[ringenesherre]

There is a number of reasons for that:

 

1) handling of read errors:

There is a quite good chance for errors while reading from any CD (audio, data or whatever). For this reason, the standard for audio CDs (Red Book) defines a quite complex and powerful error detection and error correction mechanism. In this way, a lot of small read errors can be reliably detected and corrected without re-reading the data.

 

But the error detection can also quite often detect errors that cannot be corrected without attempting a re-read. Now in a playback situation, the CD drive cannot re-read a problematic block over and over without the data stream being interrupted, i.e., the music stopping. This is not desirable and so the drive just gives up and outputs the incorrect data. In a ripping situation this is the same except that good ripping software will attempt to re-read data for a long time until it is satisfied that the block is read correct (or it is sure that the block cannot be recovered).

 

2) jitter:

The individual bits in the digital data stream output by a CD player (either to its internal DAC or to an external DAC) will not be evenly spaced. Depending on the quality of the clock of the output buffer (and possibly influence of power supply noise, RF, cable etc.), the bits will arrive at the DAC a tiny bit too early or too late. Some DACs are quite good at tolerating high levels of jitter, but others will introduce a lot of distortion due do it.

 

3) the internal DAC:

If analogue outputs are used, the digital data has to be converted into an analogue signal using the internal DAC of the CD player. Here, a high-quality CD player probably has a better DAC than a low-quality one.

 

To summarize, if you are ripping and your ripping software is paranoid enough, you will get an exact digital copy of the PCM data stored on the CD. The quality of the CD player will then only matter w.r.t. how fast the ripping can be done etc. Of course, once you want to play back the ripped files, points (2) and (3) apply here, too. The data has to be streamed to a DAC (introducing some jitter) and the quality of that DAC will influence the final result.

 

Cheers,

Peter

[sandyk]

Why does the quality of a cd player matter for playback but not for ripping?

 

With all due respect to the "Computer Scientist", it does, but not to the same extent . The quality of the power supply to the CD/DVD writer also matters.However, I will not be further elaborating on this issue as it has all been thrashed around many times before, and the "bits are bits" brigade and the subjective side are never likely to agree on this issue unless it is actually demonstrated through a far better than average system.Even then, they are likely to dispute what they just reported hearing, after later being shown the checksums of the .wav files that they heard differences between !

This subject was also discussed in HiFiCritic Vol.6 No.1.

So Peter, I suggest we leave it at this, as it is another dead end, and I will not be going there again in this thread..

Regards

Alex

[ringenesherre]

With all due respect to the "Computer Scientist", it does, but not to the same extent.

So Peter, I suggest we leave it at this, as it is another dead end, and I will not be going there again in this thread..

 

Dear Alex,

 

I full-heartedly agree that we should agree to disagree here and not reiterate old discussions.

 

Cheers,

Peter

 

P.S.: Why the quotes around "Computer Scientist"? ;-)

[mav52]

I kind a like my Rega Saturn CD player. I recently sold my Rega Apollo player and the Saturn sounds a whole lot better and I really have a hard time hearing the difference between my external dac and the Saturn. I think the ripping software makes a world of difference, I use EAC and it seems to work for me.