Does the quality of a digital signal matter?


I recently heard a demonstration where a CD player was played with and without being supported with three Nordost Sort Kones. The difference was audible to me, but did not blow me away.

I was discussing the Sort Kones with a friend of mine that is an electrical engineer and also a musical audio guy. It was his opinion that these items could certain make an improvement in an analogue signal, but shouldn't do anything for a digital signal. He said that as long as the component receiving the digital signal can recognize a 1 or 0 then the signal is successful. It's a pass/fail situation and doesn't rely on levels of quality.

An example that he gave me was that we think nothing of using a cheap CDRW drive to duplicate a CD with no worry about the quality being reduced. If the signal isn't read in full an error is reported so we know that the entire signal has been sent.

I believe he said that it's possible to show that a more expensive digital cable is better than another, but the end product doesn't change.

There was a test done with HDMI cables that tested cables of different prices. The only difference in picture quality was noted when a cable was defective and there was an obvious problem on the display.

I realize that the most use analogue signals, but for those of us that use a receiver for our D/A, does the CD players quality matter? Any thoughts?
mceljo
Mceljo,

Before you run out and buy an SACD player you might want to start another thread. Like which do you prefer to listen to more, multi channel SACD or Red book 2 channel CDs? Which gets played more often? Which do you have more of? CDs or SACDs?

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An example that he gave me was that we think nothing of using a cheap CDRW drive to duplicate a CD with no worry about the quality being reduced. If the signal isn't read in full an error is reported so we know that the entire signal has been sent.
Mceljo

Mceljo,

Not to open up another can worms, but there is differences in sound heard from a blank CDR burned on a home computer and one burned on a stand alone CDR recorder. And yes even when using "Exact Copy".
Not to open up another can worms, but there is differences in sound heard from a blank CDR burned on a home computer and one burned on a stand alone CDR recorder. And yes even when using "Exact Copy".

Since the CD copy should normally be a bit perfect copy (you can confirm this easily using a computer), you may want to invest in a better CD player or DAC. What you are experiencing are differences in sound quality due to small differences in the media disc such as weight, color, coating, central hole alignment, balance of the disc etc. - normally a good player will be immune to such differences - it should read the bits correctly without affecting the built in DAC and low jitter clock:it should result in identical sound.
Shadorne - CD copy should be bit perfect only if CD is copied as data and not as a music CD. For example - with I tunes I can make copy of CD that is not readable as data using MAX (with "do not allow to skip" option). You can make 10 copies of scratched CD with Itunes or similar program and every copy will be different (because many sectors might be on the edge of readability).

I use MAX for ripping but have few CDs that required use of Itunes to rip them because MAX with multiple attempts was failing.

The worse part is that Cross Interleaved Reed Solomon error correction code is approximating/interpolating uncorrectable data. Read what I found i Wikipedia under "ripping"

"CD audio has two major design constraints that make it difficult to obtain accurate copies in the form of a standard digital file. First, the system is designed to provide audio in real time in order to ensure continuous playback without gaps. For this reason, it does not provide a reliable stream of data from the disc to the computer.

Secondly, the designers felt that it would be preferable for major scratches in the disc to be covered up rather than resulting in total failure. Normally, an error correction system such as Reed Solomon would provide either a perfect copy of the original error-free data, or no result at all. However, CD audio's Cross-interleaved Reed-Solomon coding includes an extra facility that interpolates across uncorrectable errors. This means that the data read from an audio CD may not in fact be a faithful reproduction of the original.

Another practical factor in obtaining faithful copies of the music data is that different CD drives have widely varying quality for reading audio. Some drives are thought to deliver extremely accurate copies while others may do little or no error correction and even misreport error correction information."
Since the CD copy should normally be a bit perfect copy (you can confirm this easily using a computer), you may want to invest in a better CD player or DAC. What you are experiencing are differences in sound quality due to small differences in the media disc such as weight, color, coating, central hole alignment, balance of the disc etc. - normally a good player will be immune to such differences - it should read the bits correctly without affecting the built in DAC and low jitter clock:it should result in identical sound.
Shadorne

I knew when I posted it,... I would get that answer.... All I can say to you is, have you tried it? I suggest you try it for yourself.

I have a couple of dealers in my area that said the same thing as you. In both cases I proved them wrong on their own systems. In fact the more revealing the system the easier it is to hear the difference.

My experience the "Exact copy" from a home PC lacks the body and fullness as a copy made on a decent stand alone CDR recorder..... A couple of key things to listen for is Female vocals, and piano.

The manufacture of the blank CDR will also make a difference.
If redbook manufacture is supposed to commence play at exactly 2.00 seconds from the true zero pressed on the cd aren't we discussing data here.Programs like the forgotten Perfect Rip take this very seriously,correcting for sub-channel data in the process etc.Bit correction for offsets is what it is all about.I have discovered that Nero CD Speed Tool does report offsets correctly,just giving a total figure.Perfect Rip confirms Nero and this means that the Accurate Rip database is incorrect.All offsets given there are +30 samples out for every drive listed.I no longer get silly anamolies with ripping,they are perfect every time.I might add that voltage brown-outs and spikes badly effect ripping also.You reap what you sow.