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-   -   Yamaha Audio Master Mode on CDR (http://www.diyaudio.com/forums/digital-source/6490-yamaha-audio-master-mode-cdr.html)

MRehorst 1st October 2002 05:52 PM

Yamaha Audio Master Mode on CDR
 
Recent Yamaha CDR drives (CRW-3200, CRW-F1, etc.) have what they call Audio Master Mode in which they claim to reduce jitter by lengthening the pits and (or?) lands on the disc. This is supposed to produce a better sounding audio CD copy. The recording process is slowed to 2X, and the capacity of the disc is somewhat reduced (consistent with longer pits/lands). Can anyone who knows about these things explain why lengthening the pits and/or lands would reduce playback jitter?

Thanks,

MR

LaMa 1st October 2002 07:08 PM

The newest one can burn audiomaster mode on 8X (according to the review I read). I can't add something that is really useful :)
But I'm also interested in the ideas and technic behind it.

johnny1 3rd October 2002 03:08 AM

Well... the general idea is that with longer lands/pits it is easier for the player to decide if a land is really a land and not a pit (and vice versa of course).
This improves the laser S/N especially with the CDR / old player combination. Older CD players (before 1994) where not designed to read CDR. They can play them, but the fact that a CDR reflects back only 80% of an original CD to the laser may introduce errors.
A Greek magazine that tested a Yamaha home writer said that the trick really works, and in some cases it can give a copy with better quality than the original (especially if the original CD is scratched)...

MRehorst 3rd October 2002 03:41 AM

I was under the impression that the pick-up detects transitions, not the actual pit/land. Since the data rate coming off the disc must remain more or less constant, the disc must spin slightly faster than normal to play back an audio master mode CD. Is there some reason why spinning a little faster would reduce jitter?

MR

cowanrg 3rd October 2002 04:54 AM

the "laser" does pick up just transitions... but since its such a microscopic amount, it sometimes doesnt know if its a transition or not, because of small cd vibration or even a slight bend or blemish in the cd... this is one way jitter occurs. so, yamaha makes the pits bigger so its easier to tell a transition. this reduces jitter. so the "laser" has to do less work.

Quote:

Originally posted by MRehorst
I was under the impression that the pick-up detects transitions, not the actual pit/land. Since the data rate coming off the disc must remain more or less constant, the disc must spin slightly faster than normal to play back an audio master mode CD. Is there some reason why spinning a little faster would reduce jitter?

MR


promitheus 3rd October 2002 08:48 AM

Sounds logical so far from you guys said.
I have another question that cam up now.

If the pits and lands are a little bit longer how does the cd change the speed of the reading process? Or is this a stupid question because this is automatic in CD player ?

MRehorst 3rd October 2002 12:22 PM

Quote:

Originally posted by cowanrg
the "laser" does pick up just transitions... but since its such a microscopic amount, it sometimes doesnt know if its a transition or not, because of small cd vibration or even a slight bend or blemish in the cd... this is one way jitter occurs. so, yamaha makes the pits bigger so its easier to tell a transition. this reduces jitter. so the "laser" has to do less work.


You're talking about an error- missing a transition or detecting one wen one is not there. Jitter is a matter if the timing of the transitions, i.e. the physical location of the transitions.

I'm thinking maybe by lengthening the pits/lands you're allowing the control electronics in the burner to more accurately place the transitions. It would be easy to believe if the pits/lands were made 10X longer, but what is actually done seems like such a small difference that it's hard to imagine it having much effect on the jitter.

MR

MRehorst 3rd October 2002 12:27 PM

Quote:

Originally posted by promitheus
Sounds logical so far from you guys said.
I have another question that cam up now.

If the pits and lands are a little bit longer how does the cd change the speed of the reading process? Or is this a stupid question because this is automatic in CD player ?

CD players adjust speed continuously as the disc is played in order to get a constant data rate streaming off the disc. The data is recorded at a fixed density on the disc. That means that when data is read from the inside edge the disc has to spin faster than when it is read from the outside edge. So the disc starts rotating fast and slows down as it is played.

MR


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