In article ,
Dave Plowman (News) wrote:

Then the extra speed to read a dodgy CD rather pointless?

Depends a bit on the speed in question. Running at, say, x4 speed should be
enough to allow a re-read or few given a buffer. But CDROM drives in
computers and ripping software may tend to try and read at far higher
speeds because they (I guess) take for granted that the user wants to rip a
disc ASAP.

At some point this extra speed becomes counter-productive - either leads to
so many more read errors requiring re-reads that the rate of reliable info
extraction maxes (or falls), or means loads of mechanical noise, or both.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa...o/electron.htm
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Audio Misc http://www.audiomisc.co.uk/index.html

On 23/11/2017 10:05, Jim Lesurf wrote:
In article ,
Dave Plowman (News) wrote:

Then the extra speed to read a dodgy CD rather pointless?

Depends a bit on the speed in question. Running at, say, x4 speed should be
enough to allow a re-read or few given a buffer. But CDROM drives in
computers and ripping software may tend to try and read at far higher
speeds because they (I guess) take for granted that the user wants to rip a
disc ASAP.

At some point this extra speed becomes counter-productive - either leads to
so many more read errors requiring re-reads that the rate of reliable info
extraction maxes (or falls), or means loads of mechanical noise, or both.

Quite a lot of computer drives will slow down as they run retries, which
tends to indicate reading does get easier at low speed.

One of my CDs I found in a hedge. It plays perfectly.

The only time I've had a dodgy one was some sort of pressing problem.
The manufacturer sent me a replacement disc, and I sent them back the
old disc with a report from the CD tester we had at work. It wasn't a
speck of dust, it was all over it, and I assume they had lots.

Andy

In article , Vir Campestris
wrote:

One of my CDs I found in a hedge. It plays perfectly.

Not surprised. Often I can see no difference between discs that play fine
and the few that won't.

The only time I've had a dodgy one was some sort of pressing problem.
The manufacturer sent me a replacement disc, and I sent them back the
old disc with a report from the CD tester we had at work. It wasn't a
speck of dust, it was all over it, and I assume they had lots.

I returned a number of discs that had the 'brown rot' problem that PDO
created for a while. The replacements were all fine. But as previously
said, I also have various other discs that show problems. They are rare,
but crop up. Again, often with no eyeball detectable reasons.

Much lower levels of problems that I got with LPs back in the 1970s,
though!... :-)

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html