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Error Correction during CD replay // Super Black Hole from Herbie's Audio Lab

I tried my best but just cannot comprehend this statement from Herbie's page:  "Error correction in audio CD discs is not perfect; it is algorithm-based "guessing," not binary like in data CDs"
Why is that? and does this apply to, say, McIntosh players spinning discs at double speeds? What about CDs ripped onto HDD?
Any info or links very much appreciated.

For months now I am struggling with my Wadia 781i trying to understand why it refuses to play a few CDs from my collection. Narrowed down, at least some, to pressing defects: some CDs are seriously eccentric, when played on tiny Discmans such CDs make them jump like an unbalanced centrifuge! But only Wadia refuses to play such CDs.
sevs
georgehifi's avatar
georgehifi
10,312 posts
 
First released in 2008, 9 years ago that for a sacd/cd player is getting long in the tooth, it may need a new laser, as back then sacd/cd lasers weren't the most durable.

Cheers George  
kijanki's avatar
kijanki
4,453 posts
 
However, if error correction algorithm is engaged then I also agree this is not "perfect" and is in fact a "best guess"

Error correction and interpolation are two different things.  System will interpolate when it cannot error correct any more (gaps longer than 4000 bits).  When it is able to error correct then data is recovered bit perfect.  When you error correct you can still get expected/verified CD checksum.
Data CDs are also error corrected.  Extra bytes required for error correction waste about 15% of disk space.  For instance 700MB CD-ROM has 737MB data capacity but in reality contains 847MB.  Additional 110MB is used for error correction coding.

sevs OP
301 posts
 
Today I gutted one cheapo Discman, what is left is just a spindle motor and plastic bottom half of the player. Connected spindle motor to variable DC. At 2V / 1000+rpm some CDs make this CD-centrifuge vibrate like crazy (e.g., all CDs from German "Brain" label), some are perfectly centered (4AD label). Wadia refuses to play only eccentric CDs, treatment with AudioDesk CD lathe cures some CDs, and lowers vibration on some.
Oh, and it plays CDR, CDRW and scratch-test CD without any problems

Wadia is practically not used: until a week ago I always used Naim CDS3 for CDs. But I will open it up tomorrow (I did this before, to reset its "gain" switches) to check its CD mechanism.

Cannot wait to get to the fun part of different color markers for CD edges!!!   :-)
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