Why does CD sound better copied?

Status
Not open for further replies.
Jump to Latest
#121
kiraly said:
As a pro, regarding digital signal conversion, I have some comment to this discusion about copying music to CD /HDD

When playing a CD on a normal player, there are some bit errors, making necessary for re-read the disc (read: causing delays in conversion), that the player correct by interpolation each time there is a read error, this is a natural part of playing a CD, however when once recorded on a new CD media or HDD, the bits of the original material have been corrected, and all read errors have been corrected when stored on a new media, when re-playing from the new media CD/HDD, there are no errors, and no need for re-read, causing no delays, and lower jitter. Of course a copied CD will by time also get scratches, and need re-reads, here the Hard drive wins.

I am working on a project (professionally) with a high-end Integrated amplifier with built-in Harddisk, for High End music reproduction.
Click to expand...

The delay in conversion is utter nonsense.

Normal discs that aren't severely damaged, can be read back, retrieving all data originally available on the disc. Th EFM coding is made such that sufficient redundancy is available to restore EEXACTLY the original data.

If not, in audio systems, the interpolator does his job.

When a disc is copied to CDR, its' data is exactly similar to the data on the CD. That can be easilly checked, using todays' software.

The only remaining diference is pit-jitter

best
 
#123
kiraly said:


When playing a CD on a normal player, there are some bit errors, making necessary for re-read the disc (read: causing delays in conversion), that the player correct by interpolation each time there is a read error, this is a natural part of playing a CD,
Click to expand...

To elaborate a tiny bit on Guidos valid comment, CD players do not reread anything. Contrary to data CDs, the ordinary audio CD format contains no form of sectoring or sync information (on lower level than tracks) that can be used to sync in if trying to reread. Hence CD players are not built to do any rereading. The format itself has error correction on two levels, plus a clever sample interleaving to cope with certain types of errors without more degradation than temporarily halving the data sample rate. In addition to that, it has interpolation to minimize the damage when consecutive samples irrecoverably lost.

When reading an audio CD in a computer drive, a clever program like EAC can reread the data, but it can take long time because of the simplicity of the data format. I think EAC uses some clever algorithm to try syncing in by using pattern matching to try avoiding rereading tracks from the beginning, but I am not sure of that, and it presumably takes a lot of computing power to do so. Theoretically one could build a CD player with a very fast CD-ROM drive that uses a combination of buffering and rereading, but apart from the small advantage, it would have disadvantages like noisy CD-ROM drives spinning at high speed, the need for a powerful computer and a large buffer memory and then still not being guaranteed that it can succeed to read the correct data in time to avoid buffer underflow.
 
#124
christer, wasn't there some company in the states who recently made a cd player that rips to hard drive using a multi read-till-right algorhythm.

basically EAC to hard disc and then reads off disc throguh buffered jitter free FIFO buffers.

it was either absolute sound or audiphile where a coupleof the reviewers dropped the $10k for there own personal use.
 
#125
sq225917 said:
christer, wasn't there some company in the states who recently made a cd player that rips to hard drive using a multi read-till-right algorhythm.

basically EAC to hard disc and then reads off disc throguh buffered jitter free FIFO buffers.

it was either absolute sound or audiphile where a coupleof the reviewers dropped the $10k for there own personal use.
Click to expand...


Perhaps, but that would be a rare exception. Of course one can build such a player, just as I suggested. If it rips the CDs to hard drive off line (ie. one does the ripping once for each CD and before listening to it), then one could get around the problem with noisy CD-ROM drives and potential buffer underrun. Of course, hard drives are not exactly silent either, so that would have to be acoustically isolated and the computer in the player would have to run with passive cooling to be silent etc. But it is all possible. We have the technology.
 
Status
Not open for further replies.
Top Bottom