Burning CDs Degrade Quality?

quote:

a digital transfer should be perfect copies of the original

If that is the case you should be confused when you discover that your copies are noticeably inferior to your originals.

Bob

This has been covered a few times, mostly in The Padded Cell, so search there for particulars. Copying at 1X speed is a good place to start on improving the quality of your copies.

quote:

Copying at 1X speed is a good place to start on improving the quality of your copies.

I've tried this - the copy still sounds inferior. Fine for the car etc: but not for serious listening on a good system.

John.

Which burner-softwear do you use?

I copy at 8x and can detect no difference.

On a good system Nigel?

My 'real-time' copies lack space and ambience, and sound a tad raw.

I'm using 'Nero'.

John.

I think the difference is small - and for a party situation negligable

but for serious listening hten yeah go the original

I do my copies at 4x using Nero. They sound slightly different to the originals, can't put my "ears" on what that difference is though.

Howard

quote:

Originally posted by J.N.:
On a good system Nigel?



John.

On my system, which is the only one that counts for me.

quote:

I think the difference is small - and for a party situation negligable

but for serious listening then yeah go the original

Yes Jason; that's a good summation.

John.

I've got a few copies, all of them indistinguishable from the original. I've used Exact Audio Copy to compare the original and copied WAVs and generally found them to be identical. Occasionally there are trivial, microsecond differences at the start of a track but no more than that. Whatever causes the copies to sound different (and I have so far detected no audible difference) it's not the digital copy process.

Now that i'm getting used to things, I can hear that the copies lack a bit of the detail of the original. Fine for the car, the portable or background music. I definitely won't use them for auditioning the CDX2 tomorrow. Thanks for the help.

Then I'd suggest you want to look at how you're copying them, and the blanks you're using because if you're doing it properly you're listening to the same bit stream.

I use a Mac with the software "Toast." Sounds pretty good to me. I wonder though for those of you critial CD listeners if these blanks from Mobile Fidelity might help.

john

quote:

Originally posted by TomK:
I've got a few copies, all of them indistinguishable from the original. I've used Exact Audio Copy to compare the original and copied WAVs and generally found them to be identical. Occasionally there are trivial, microsecond differences at the start of a track but no more than that. Whatever causes the copies to sound different (and I have so far detected no audible difference) it's not the digital copy process.

EAC is excellent. However, I would be interested if anyone could be bothered to copy a CD, make a copy of the copy, make a copy of the copy of the copy - say, ten times.

I doubt the resulting CD would still confirm the total robustness of copying in the digital domain.

If right about this - there must be losses in each of the stages. Are these important? If you can hear them - yes.

Also, copying is illegal.

I would say that a copy of a copy of a copy * 10000 times (using verify of course) will result in the final copy having exactly the same data as the first copy. It is digital after all.

Mike

Adam,
Why should you think this? Assuming the EAC compare functionality does what it claims to do the copies I've made have been clones of the originals apart from the occasional microsecond differences at the start of a track. On one occasion the checks showed minute errors in the originals which were corrected in the copies. These were audible as occasional ticks on the original and the listening tests showed that the error correction had done its job i.e. they were gone.

The sort of effects claimed on here - "loss of detail", "loss of spaciousness" etc would require wholesale differences through the whole WAV and would probably result in a failure to do the compare (EAC stops if it finds what it thinks are completely different WAVs). This has never happened. I'll repeat that whatever is causing the differences people on here claim to hear (not me I add) it isn't the digital copy process.

It just ain't as simple as the bit-stream being the same.

The fact that Japanese made CD's always sound better than their EU made equivalent, proves that you only have to so something slightly different in the manufacturing process, to make a CD sound better/different.

John.

J.N. that's the point I'm making. There was a thread on this topic a few months ago where there were several claims made that the digital copy process was somehow losing this bit or that bit or some other bit and that was what was causing the degradation. This is simply not the case and if there are differences (and I have not heard any) then it's caused by some other part of the process. Perhaps the error correction circuitry is having to work harder on a copy which makes it more difficult to retrieve the data in real time. Who knows?

However I stress that I have not heard a single difference and have several copies being used as my primary source (my son and I occasionally share CDs where he has the original and I have the copy or vice versa). All playing quite beautifully on my CDX2/XPS2 without a hint of a problem.

I can't detect any difference between a copied CD and an original.

A friend uses burned CD's in a portable CD player [so as not to damage the originals]. He finds sonic differences between different brands of blank CD [prefers Phillips to Sony].

The burned CD could be identical [bit-wise] to the original but the reflectivity is less and some players may have a bit more trouble reading a CD-R than a CD. Ditto for different brands of CD-R [based on different dye formulations].

There is also an argument that reading a CD to hard-disk and playing it back from disk should give better results than playing it 'live' with the same computer/soundcard because 'ripping' [with a good program] does multiple reads to correct any errors; 'live' playing just interpolates errors. I have not tried this. Also I have no idea if using the hard-disk playback would give less jitter.

So I think it's quite possible that with the right [or wrong !!] combination of disks / player the recorded disk can sound worse but mainly because the player is having trouble reading the disk.

James H.

Lets face it.. if you are copying music cd's for alternative uses around the home etc you might be grateful one day that you copied it, especially if the original goes missing and you cant buy it anymore!!!!!!!!!!!1

James,
I think that's fair comment. The problem (if there is one) is not with the digital copy process itself as some suggested here a few months ago (based to be honest on a load of technical nonsense from Linn as far as I remember).
If some folk claim they can hear differences I'm not going to argue. I spent much time many years ago convincing myself that the 30amp cooker cable I was using for my speakers sounded better that the rest, when the only tangible result was that it almost ended up ripping the connectors off the back of the speakers!

TomK,

My Marantz CD player can play original CD's, CD-R's but not CD-RW's [it's quite old]. I presume it has a bit extra trouble with CD-R's.

James H.

Hi All,

Some interesting arguments.

I had a debate with my brother regarding this a few years ago and we did a (digital, verified)copy of a few diverse tracks and listened for differences.

We didn't hear any differences, and the points we agreed on can be summed up as follows:

*If bits can indeed get mangled as a result of the CD plastic having a different opacity and/or refractive index and/or colour, there is just as much chance that the most significant bit will get lost/misinterpreted as the least significant bit i.e. we'd expect to hear some audible 'ticks' every now and again.

*We know that the audio stream is whizzing past at great speed and that perhaps a mangled bit of a music signal might be audible to some and not to others, but what about using the same quality CDs for computer information, where almost every bit counts? (I say almost every bit because its possible that data CDs are written with SEC/DED algorithms such a single error in a word can be corrected, and a double error can be detected yet not fixed.) If two bit errors occur in the same word, even if you have a SEC/DED algorithm, for computer usage your CD is effectively useless. Neither of us has ever heard of or seen this happen - discs we burn and verify always come up fine, which leads us to believe that the bits are written to the disc accurately and are able to be retrieved from it also. Plus a bit error would be detected in the verification process so if the disc passes verification it should be digitally 'perfect'.

Just possibly the drive in the CD player might have difficulty reading a CD written by a PC drive(I haven't rigged up a test whereby I listen to a CD on a PC, copy the CD on that same computer and then listen to the copy - I used my CDX2 as playback). Yet if such a drive was to have a difficulty with the plastic of the CD, surely there would be LOTS of errors, very frequently, often involving the more significant bits of the word, so basically there would be lots of 'bthht' noises and ticks etc or a complete failure to play the discs at all (such as James H's Marantz player). Also I'd be surprised that a cheap drive in a PC would be so much better at reading a disc spinning 8 or 16 times faster than a single speed drive in a CD player - both CD player drives and drives for PCs are made in huge numbers so economies of scale apply equally to each (OK, maybe in favour of PCs but we pay a lot for the drives in our CDPs so can expect a quality item).

Given that some of my original discs have plenty of scratches and fingerprints on yet still sound fine, I find it extremely hard to beleive that a CD material of a slightly different colour, which has been verified OK and (if produced as a data disc) works fine to store data for a PC would fail to perform as well in an audio CD player.

The only time I have heard a difference between digital sources was when jitter was either deliberately allowed or re-clocked and eliminated. As far as I can see it is only jitter that represents a 'soft-underbelly' that threatens the integrity of the digital transmission concept.

Feel free to flame me while I'm away - I'm going hiking in Switzerland now!!

Regards,

Richard.