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RE: CD Burn Rate

Subject: RE: CD Burn Rate
From: Dan Dugan <>
Date: Fri, 13 Dec 2002 11:55:25 -0800
DAN DUGAN
>  >But the RF levels I'm getting with Mitsui Golds is only adequate, 10%
>  >less than I got in the golden age of 63- and 74-minute CDRs.

PAUL ISAACS
>You only need be concerned about RF levels when they are very low.
>From my experience, if you have one disc with 70% relectivity and another
>with 60% reflectivity, it does not follow that the quality of recording is
>better on the higher reflectivity disc. I have found that reflectivity above
>60% is more than adequate and ensures good compatibility .

I wonder how reflectivity correlates with my crude relative RF level 
measurement. I think the raw RF level is more related to contrast 
(difference between pit and land) than reflectivity. And in my 
experience this measure is well-correlated with playability.

>What is more
>crucial is the ratio of the rf level coming from the shortest pit (3T) to
>the rf level coming from the longest pit (11T).

I think by metering the pickup preamp output, I'm looking at a slow 
average of pit to land, not short to long pit ratio.

>This should ideally be much
>less than '1' otherwise the CD decoder can get confused and misinterpret the
>length of pits.
>
>This is just one aspect of the quality of a disc. Reflectivity might be
>great, but problems can still occur - e.g. jitter
>
>>Please Paul, can HHB provide a hotter 1x-4x CDR?
>
>As already explained, hotter does not necessarily mean better. It is more
>crucial that you get a good overall balance of parameter specifications.

I agree that there are lots of things I'm not measuring, but when I 
can only get around 80% modulation off Mitsui Gold discs where I used 
to get over 90% with older stocks, and below 75% fails on older 
players, I want more margin of reliability.

-Dan Dugan


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