CD copies?
Nov 12, 2004 at 2:06 AM Thread Starter Post #1 of 19

Beach123456

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When you copy a CD with a CD burner, does the CD lose any of its original quality?
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Nov 12, 2004 at 3:57 AM Post #2 of 19

recephasan

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Yes, most burner software reads the CD once and writes what it sees. Even worse with CDs with 'copy protection' where the error correction screws up the original data and writes 'wrong' stuff into the copy CD.

use EAC if you're gonna do this (and nobody else in this forum does it, y'hear?), make a single wav file of the entire cd, with a cuesheet and use a burner software like Nero that can make use of that cuesheet, otherwise you'll have a perfectly copied cd all bundled into one track.
 
Nov 12, 2004 at 5:11 AM Post #3 of 19

Stephonovich

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Evidence of quality loss is sketchy at best. I still take precautions such as using EAC in secure mode, offsets corrected, and burning fairly slow (8x). I figure if I cover all my bases, bunk or not, I ought to be safe.

In theory, eventually you'll lose a bit here and there due to poor media, burner messing up, or what-have-you. Whether or not you'll notice a difference is doubtful, though. Consider the sampling rate of a CD... 44,100 per second, or 176,400 kbps (44,100 samples*16 bits*2 channels/8) At that rate, it's highly unlikely you'd notice a sample or two missing. The error protection is quite good.
 
Nov 12, 2004 at 5:19 AM Post #4 of 19

citywithoutmetal

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I've burned about 45 cds with nero "cd copy". an iso is created then it's burned promptly. every cd has worked on my pc so far even the multimedia. so all those cd's aren't exact copies? sigh, can anyone find out for me what the truth is?
 
Nov 12, 2004 at 5:25 AM Post #5 of 19

Stephonovich

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Obviously they'll work. The question is if you're anal enough to care about, say, 1/76th of a second of missing audio. (about what my burner will do if you don't use EAC and correct offsets) You're not going to hear it, even if you're trying. Error correction will cover it up for you, and your brain will do the rest. It's just the principle of the thing; it's not a 100% bitperfect copy. And yes, I have ripped originals and my copies and found they are exactly the same.
 
Nov 12, 2004 at 5:34 AM Post #6 of 19

Blue Meanie

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Quote:

Originally Posted by citywithoutmetal
I've burned about 45 cds with nero "cd copy". an iso is created then it's burned promptly. every cd has worked on my pc so far even the multimedia. so all those cd's aren't exact copies? sigh, can anyone find out for me what the truth is?


Even if they aren't "exact" copies, if you're listening through average computer speakers, you'd never hear a difference. Probably wouldn't even be able to tell on a fairly high-end audio only 2-channel system. I wouldn't bother sweating over it...
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Jeff
 
Nov 12, 2004 at 5:59 AM Post #7 of 19

enzoferrari650

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yeah, i've made tons of copys. I doubt you'd be able to tell even on the most top notch hi end systems there are. Maybe a slight bit if you are trying to find it.
 
Nov 12, 2004 at 9:04 AM Post #8 of 19

recephasan

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No, no and no. I'm sorry but you guys are wrong.

There are the 16 bits to every sample and then there are extra bits on every CD.

I've listened to a CD (with copy protection) on a Rotel which played it just fine but my DI/O simply crapped out with it, all kins of bad sounds. There was not even a scratch on it.

And about multimedia CDs, my copies of WC3 on Panasonic burners with Nero never start, so they are not exact duplicates. All the useful data is there, but still the copies are not identical.

Edit:
Yeah, on most CDs, esp. older ones, there is no copy protection and if the CD is clean, it will copy just fine. But some will not.
 
Nov 12, 2004 at 12:23 PM Post #9 of 19

Blue Meanie

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Quote:

Originally Posted by recephasan
No, no and no. I'm sorry but you guys are wrong.

There are the 16 bits to every sample and then there are extra bits on every CD.

I've listened to a CD (with copy protection) on a Rotel which played it just fine but my DI/O simply crapped out with it, all kins of bad sounds. There was not even a scratch on it.

And about multimedia CDs, my copies of WC3 on Panasonic burners with Nero never start, so they are not exact duplicates. All the useful data is there, but still the copies are not identical.

Edit:
Yeah, on most CDs, esp. older ones, there is no copy protection and if the CD is clean, it will copy just fine. But some will not.



Well, maybe you just suck at copying CDs...Just kidding!
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Just to clarify MY opinion, I wasn't referring to copy protected discs in my reply.

Jeff
 
Nov 12, 2004 at 2:07 PM Post #10 of 19

blessingx

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I think I've only seen two copy protected audio CDs ever (though I'm on a Mac so may not have noticed some of the Windoze auto-load issues), but if you trust verify or info programs they appear to be exact copies (in information not placement).

Now can a bit drop off in copying? Sure, just like an occasional pressed CD does also (we've all returned a CD over issues at least once right?). I really think you have much more to worry about CDRs becoming increasingly unreadable as time goes on.
 
Nov 12, 2004 at 2:12 PM Post #11 of 19

bangraman

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Quite apart from the degeneration of CD-R's there's plenty of evidence with my own ears, and the even more sensitive ears of an A&R friend of mine (who can tell the difference between the original CD and a quite well burned copy of it on a boombox
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) that some copies are worse than others. EAC will do a good job but it is labour intensive. Others may not.
 
Nov 12, 2004 at 4:15 PM Post #12 of 19
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Quote:

Originally Posted by bangraman
Quite apart from the degeneration of CD-R's there's plenty of evidence with my own ears, and the even more sensitive ears of an A&R friend of mine (who can tell the difference between the original CD and a quite well burned copy of it on a boombox
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) that some copies are worse than others.



I did research this problem quite seriously few years back in a process of Creek CD53 design. Yes, there could be a difference in the sound between an original "silver" CD and a bit-perfect copy of it. This difference could be heard even on a medium quality equipment. Moreover, usually it is easier to spot the difference on such equipment, thought I didn't actually try to do it on a boombox
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. I found that there are ways to minimise (or more precisely illiminate for most purposes) this difference. Main source of such difference is not in a digital domain at all, but in a purely analogue domain. Put it simply, the servo system of the player, especially the laser tracking part of it, is a single most powerful source of an audio frequency electrical noise in the player, mostly into the power supply. There is a difference between how a pressed disk or a burned disk are affecting the servo - the spectrum of the interference does change somewhat and this is what in my experience does change the sound. There are several different ways how this noise could affect the sound - from direct coupling to the audio output of the player, to a different jitter components in the DAC and on the SPDIF output.

Alex
 
Nov 13, 2004 at 12:31 AM Post #14 of 19

Alu

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I use EAC (www.exactaudiocopy.de) as well, using the following method :

1) Use EAC (Exact Audio Copy) to Rip your album.

(Under EAC -> Drive Options Menu)

2) Under Extraction Method use Secure Mode
3) Under Drive select Spin Up Drive
4) Under Writer detect write features
5) Under Writer create an offset cd
6) Under Offset/Speed detect read sample offset correction
7) Under Gap Detection select Secure for Detection Accuracy

(Under EAC -> EAC Options Menu)

8) Under Extraction select High for both Extraction and compression priority
and Error Recovery Quality

9) Then begin Ripping your cd.

10) After Ripping check your log. If there are no errors (ignore the >100%s on
track qualities) create the log and save it in the ripped directory.

11) If there are errors either delete the tracks and/or rerip them until you have no errors.

BTW, does it really affect the quality of an audio-cd when burning it with various speeds? I always burn them with 24x.
 
Nov 13, 2004 at 3:09 AM Post #15 of 19

wolfen68

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Quote:

Originally Posted by recephasan
And about multimedia CDs, my copies of WC3 on Panasonic burners with Nero never start, so they are not exact duplicates. All the useful data is there, but still the copies are not identical.


Copy protection issues aside, remember that a burned disk is "different" than an original factory disk EVEN if it is a bit perfect copy. Different devices may respond differently to a burned disk since it a different type of "etching" (maybe a bad analogy) than factory pressed.

Now you get into issues of device laser strength and general compatibility issues. I beleive antonik is also commenting on this phenomena (with more detail) and I agree.

I'm significantly more concerned over cd-r longevity than I am on hearing a sound difference between the original and burned. One study I read showed cd-r's of many brands beginning to fail after only two years after being exposed to reasonable temperature/humidity cycles.
 

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