[miklorsmith]

Ooo ooo.  I'm with Clark on the CD-R thing.  I've got a dedicated burner and I'll soon have my "shootout discs" back from George Louis.  Thanks, Clark!!  Didn't know George was back.

Cleaning the CD is Definitely Not all that can be done.

And, when the 626 kit is done, let me know so's I can cut the check.

[skrivis]

Ooo ooo.  I'm with Clark on the CD-R thing.  I've got a dedicated burner and I'll soon have my "shootout discs" back from George Louis.  Thanks, Clark!!  Didn't know George was back.

Cleaning the CD is Definitely Not all that can be done.

And, when the 626 kit is done, let me know so's I can cut the check.

Assuming that there is a difference, what would be causing it?

If the bits are the same (this can be tested), then why would there be a difference?

I'm not big on "magic" as an explanation. (That includes "magic" wire...)

[miklorsmith]

Good copies place the pits/lands more precisely than the physically torn ones of the original CD.  The CD-ROM drive can read the original over and over and over until it's sure it's got the right sequence before encoding  as a file.  Original CD's force your CDP clock into the compromising position of translating and correcting a larger number of ambiguous readings in real time.

If you don't think your CDP is struggling with real-time math problems, try plugging a non-OS DAC into the system (less math).  

Of course I don't understand the science.  This represents an amalgam of my reading and first-hand experience in several systems.

[ScottMayo]

Assuming that there is a difference, what would be causing it?

If the bits are the same (this can be tested), then why would there be a difference?

Having some idea how common it is to make a bit perfect copy of a CD in a standard rip operation, it's going to be hard to test the assertion. But I'd be willing to state that if you do get two discs which are verifiable as bit perfect copies, that they will sound identical in an ABX test, no matter how they were made. If the bits are the same, a CD player that produces different sounds from them is seriously broken.

[CornellAlum]

Scott, I am shocked at this response

I have read  multiple places that a copied cd sounds better than the original, I think I will have to try it.

[ScottMayo]

Scott, I am shocked at this response

I have read  multiple places that a copied cd sounds better than the original, I think I will have to try it.

By all means. This at least is a tweak that doesn't cost much.

But do it fairly. Buy a new CD, and copy it *first thing*. Now compare the original and the copy for bit differences. If there are none, then do your ABX listening test and see if you can pick out the copy.

If you can, then I think the good folk at Phillips (and the various CD manufactuers) have a lot of explaining to do. How dare they sell us originals when they could be selling us copies!  

Besides, we can all make copies of copies, and it will just keep getting better, right?  

Of course, if it's true that error correction is making it all better, then we need to get out our pitchforks and torches, and storm the manufacturers of CD players. Because if the error recovery strategy of a good duplicator is really that much better than what a CD player does, then the CD player ought to be redesigned to do the same thing: read the disk at 8x or more, reread questionable sectors, and error correct the bits into memory - and then play the music from memory. It's not like a half-gig of memory costs much anymore...

Though an SACD player designed along those lines might get a little expensive.  

[skrivis]

Good copies place the pits/lands more precisely than the physically torn ones of the original CD.  The CD-ROM drive can read the original over and over and over until it's sure it's got the right sequence before encoding  as a file.  Original CD's force your CDP clock into the compromising position of translating and correcting a larger number of ambiguous readings in real time.

If you don't think your CDP is struggling with real-time math problems, try plugging a non-OS DAC into the system (less math).  ...

Do CD-ROM drives read over and over? How do they determine what's correct if the physical surface of the CD is questionable?

Are the pits/lands on a CD "torn?" This is the first I've heard of that.

CD-ROM drives generally read at faster rates than a CD player. Wouldn't that make problems _more_ likely?

CD-ROM data disks read at much higher rates don't seem to exhibit errors - otherwise you'd see more errors with software. Video has more data than audio, and I don't see that there's any problem keeping up...

The DAC can either keep up or it can't. I don't see why a non-OS DAC would be better; in fact I'd think it would be worse because of the requirement for steeper output filters.

[Tim S]

In fairness to those who believe the copies improve the sound, it is not the act of copying that supposedly makes the improvement. It is the particular (usually black) cd that is used in place of the original. The idea is that something about the color or construction of the cd helps the cd to read it better. If they really are better then you are right that one has to wonder why they don't sell the original ones on the same black cd's. I've never tried it myself so I have no idea.

Tim

[ScottMayo]

Do CD-ROM drives read over and over? How do they determine what's correct if the physical surface of the CD is questionable?

http://www.cdrfaq.org/faq02.html#S2

Down around [2-43] it talks about the physical format. Read it, and then ask yourself what a device like the "Intelligent Chip" is supposed to be "upgrading".

In general, you can tell a CD-ROM to reread a file or a track as many times as you like, and compare the data. Whether rippers actually do this is another question, but uncorrected errors are reported by CD drives, so software can in theory be written to know it's being handed known bad data, and try again. Some software definitely tries this. I've seen operating system drivers go mad trying to do this with bad disks; there's the legend about the iMacs that locked up on some particular album.

Whether reading at higher speeds increases the error rate depends on the quality of the electronics. The bits are never flying by faster than electroncs can be designed to clock or photons can bounce, so the only issue is the tracking ability of the laser. Reading audio data at 16x is feasible. What's hard to do is seek backwards to an exact point on the disk that you've already passed (other than the beginning of a track or file) - apparently the redbook didn't include support for that - so "retrying a sector" is apparently a bit of a trick.

[miklorsmith]

This isn't the best place to have this discussion, but here goes:

Scott, don't get too excited on the "no difference possible" angle.  If you don't hear the difference in Clark's discs, I'll have pretty serious doubts about your ears.

I've discussed this before.  Read Gary Koh's article on the Genesis website.  His thought is that it's a combination of factors that produces the best result:  Good ripping software on a dedicated computer (preferably a laptop with external drives), then burning at slow-ish speeds with a good burning drive.  He says a power conditioner (PS Audio Power Plant in his article) is important for Best results.  The ROM drive doesn't automatically re-read every sector, but good ripping software can instruct multiple reads to ensure proper encoding.

This is the system I've built and it unequivocally works.  My uninterested friends agree.  I haven't played around with standard computers or compared between different blanks, though I generally use Memorex blacks.  When a friend and I visited Mr. Koh in his factory, we were immediately able to tell differences between different blank discs, though this was on a pair of $45k speakers.

Original CD's are physically pressed to create the impression ultimately played on your CDP.  These dies are very fast in production but wear out over time.  Try to imagine a die with the tiniest impressions pressing the aluminum sheet to its likeness.  Do you imagine a perfect match, or would you expect the aluminum to have some less-than-square edges?  How would you imagine diagonals to be interpreted by the CDP laser?  Pit or land?  Yes or no?  One or Zero?  This problem compounds as the dies dull.  Discs pressed later in production cycles are much more flawed than ones pressed early.  Cheap studios don't like to keep producing expensive press-dies either.

Burning them would be impractical from a production standpoint.  And, most CDR's have unstable ink that degenerates over time.  So, better keep those data files you ripped.  These files are very handy for future encoding as flac or .mp3 files BTW.

I believe the new Cary players are using CD-ROM drives, as they are reportedly far superior in jitter reduction than CD transports.  Why don't your cymbals sound like a stick striking metal?  Why isn't your bass as tight as you'd like?  Why haven't the Great Engineers of the Digital Age done a better job with all this stuff?  Your CD's can be improved, significantly.

And, if Mr. Louis' method is better than mine, I'll send him a check right away.

[clarkjohnsen]

Clean the disk and it's as good as it will get.

Have you proof of that assertion? Any, at all?...

Moreover you seem to dismiss the CD-R phenomenon, where the bits are all the same but the disc sounds different, usually way better. An impossibilty, you would claim.

I would tend to conclude, in this case, that the bits are _not_ the same. :)

Alas, alack, the bits are no more changed in a plain copy than they are by cleaning the original.

Gentlemen, the problem lies in the optical player, not in the production.

clark (former optical engineer)

[clarkjohnsen]

If the bits are the same, a CD player that produces different sounds from them is seriously broken.

Are you listening? OK...

ALL CD PLAYERS ARE SERIOUSLY BROKEN.

clark

[skrivis]

If the bits are the same, a CD player that produces different sounds from them is seriously broken.

Are you listening? OK...

ALL CD PLAYERS ARE SERIOUSLY BROKEN.

clark

That sounds rather final. I guess we should just give up on them then.

[Marbles]

That's why I'm going to a PC based transport in my REF system.....

[Russell Dawkins]

miklorsmith,
my understanding is that CDs are made with an injection molding, not stamping, process and that aluminum sheet stamping never comes into the picture, regardless of which of the three (in 1994) manufacturing methods are used. The aluminum or gold is vapor deposited after the pits are formed in the mold. Nevertheless, I would assume that deterioration of the mold is a factor.
I found these descriptions of the process with a Google search:
http://www.ee.washington.edu/conselec/CE/kuhn/cdaudio/95x6.htm
http://www.ee.washington.edu/conselec/W94/edward/edward.htm
Russell

[zybar]

That's why I'm going to a PC based transport in my REF system.....

AMEN!

[woodsyi]

That's why I'm going to a PC based transport in my REF system.....

From what I gather, you are going with I2S Off-Ramp.  Let us know how it goes.  If only it had wireless.........
I think this thread has now been officially hijacked........    

[Marbles]

That's why I'm going to a PC based transport in my REF system.....

From what I gather, you are going with I2S Off-Ramp.  Let us know how it goes.  If only it had wireless.........
I think this thread has now been officially hijacked........    

 

Still at least a month away..but you are correct.

[miklorsmith]

Well that shows how much technical know-how I have.  I have read a lot of overview-type documents about the process and that's the impression I had.  Sorry for the misinformation, it wasn't malicious.

Avoiding the mechanics then, suffice it to say that burning and manufacturing processes ARE different and DO create a different medium to be read.  My subjective interpretation is the burning method produces a superior result.

[clarkjohnsen]

If the bits are the same, a CD player that produces different sounds from them is seriously broken.

Are you listening? OK...

ALL CD PLAYERS ARE SERIOUSLY BROKEN.

clark

That sounds rather final. I guess we should just give up on them then. :)

Perhaps!

However, I would advise (and have so advised for fifteen years) simply not to drop big bucks on any of them. My fine-tuning procedures produce results on a decent Sony, say, that easily equal the dcS and Wadia efforts.

Moreover, were we never to admit how "broken" they all are, the truth of the matter would forever lie undiscovered.

clark