Q for Steve... CD or CD-R

I said I was done, but for clarity I'm going to jump in again.

It is possible to get some errors when copying an "audio" CD -- it should never happen with a "data" CD; if it did programs on the CD would crash and burn -- but for the sake of this discussion we were actually discussing disks that are, bit-for-bit, perfectly identical, and how it might be that they don't sound identical.

 

Steve,

What you are saying makes all the sense in the world.
An audio CD copied on a computer then is copied as data bit for bit.
I'm not sure where this jitter and smearing that everyone else is talking about comes in to play when copying an Audio CD to a CDR on a computer.

I beleive that everyone is a bit confused. Pardon the pun.

I'm not a debator, that's not why I'm here. I'll go with the flow. No points here to prove from me.

Everyone's point of view is a bit different. When someone in this thread
has written a thesis or a book on the subject, then
I will be a true believer. Unless they can cite their source and I can see
it in print from a leader in the field.

Until then, it's all theory or opinion. But very entertaining nonetheless.

I just don't take it too seriously.

Let's keep it light and fun.

 

The audibility of jitter may be overrated. I jsut noticed this by Arny Kruger on RAHE:

//
The audibility of jitter has been studied very thoroughly. A landmark
paper in the area is: Theoretical and Audible Effects of Jitter on
Digital Audio Quality. Author(s): Benjamin, Eric; Gannon, Benjamin
Publication: AES Preprint 4826; AES Convention 105; September 1998

This paper concludes by saying:

" The influence of jitter in causing audible distortion was found to
be less than anticipated by the authors, and less than that predicted
by both the technical and consumer audio press. Jitter induced by the
digital audio interface was not found to be an audible problem for
any of the program material auditioned."
//

It would be interesting to find out what material was auditioned, on what equipment.

here's a link to the post:

http://www.google.com/groups?q="[email protected]&rnum=1

 

Now were finally getting to documentation -Arny Kruger. Very highly respected.

Now in talking strickly about CD Rom Drives in Computers
The CD data is supposed to be duplicated to the CDR unless some of the data is corrupted somehow? Otherwise CDR has the same data as the CD?
The jitter occurs in the spinning of the CD or optical lense in the transport and it affects the sound as it is converted back to analogue and heard through the speakers? If neither the CD nor the Lens had to rotate then
the jitter would be illiminated? A novel idea.


Thank you Krabapple. Great stuff.

 

"Publication: AES Preprint 4826; AES Convention 105; September 1998"

I strongly disagree Krabapple. This is another area where science has consistently fallen short. I was able to clearly identify differences in the sound quality between an Alessis MasterClock at 176ps and a Lucid Audio GenX 96 at around 40ps...More instrument delineation, more individual voice reproduction in choirs.

I am putting together an experiment where I will mail people a CD with high jitter and low jitter transfers and ask them to identify the better sounding tracks. This fully blind test will be ready to roll by year end.

If you heard the effect of adding the GenX in my system, you would be convinced how audible jitter can be in even the picosecond range.

By the way, while AES numbers are nice, the AES is notably anti-high end. They were slow to even acknowledge the existence of jitter and the fact that ultrasonic noise in Super Audio can be reduced by dither. Also posting the numbers is less effective as the AES charges for the actual full paper.

 

Are you guys talking about jitter at the mastering stage of the CD or just the copying of an already released version of a CD to a CDR in a CD ROM
Computer drive?

 

Grant, the track that really gets me is..."Already Gone"! In comparison to the original Greatest Hits, it's incredible! Try it for yourself...you'll be amazed.

 

Hi Lee,

Everyone enjoying this thread will be very interested in your findings.

 

Lee,

I'd be very happy to loan you my ears in your experiment. PM me and we'll talk.

 

I have not read all 8 pages of this topic.
Only 1, 2, 7, & 8.
So if I missed this, oops!

I'd heard [pun intended] that CD-R's that do multi-formats, CD, DAT, etc., because of DAC's converting multi-sampling rates can not or don't make 'prefect' copies.

Anyone?

 

Grant,

Have you compared the SH CD to the DVD-A?