Thread: Toshiba SD-M 1612 C2 ...

Hi there ... just a warning to all Toshiba SD-M 1612 owners ... do not trust C2 ... I just did a test with a badly scratched disc ... while the C2 read mode did not report any errors and ripped the disc at 15-17x, the non-C2 read mode ripped at 7-8x and showed some error correction re-reads (no read or sync errors, though) ... after comparing these two images there were some different samples ... if C2 should be working correct on this drive, this should not be the case ... or am I completely wrong about C2 ?

My choice is to deactivate C2 on this drive and wait a little longer for the rip ...

Just my humble opinion,

It seems to me the only drives that NEVER have problems with C2 error correction are the Plextors (or the TDK VeloCD drives, which are repackaged Plextors).

Or am I wrong about that?

And the rest of this message is for Andre:

Just wondering if you considered making some sort of warning in EAC telling them that C2 error correction likely won't work with their drive unless they have a Plextor?

I'm betting there are many people out there who falsely assume that their drive supports C2, and keep it on because EAC will rip much faster with it turned on.

To me, EAC is so valuable because of the quality it provides. I realize you could say the same thing about the other options that must be set correctly for accurate ripping:

Caching: - the test in EAC isn't wrong very often
Accurate Stream: - pretty much every drive made today supports this

It's the C2 that bothers me, because the 'test' for it is often wrong, and even when it's right the drive rarely supports it correctly. Anyone who doesn't take the time to read through the EAC forum or newsgroup won't realize this.

I just thought there might be a way in the EAC software itself to make sure the user knows exactly what these options mean, and a specific warning about C2.

chris

All right ... did some more thorough testing last night ... ripped the given CD 4 times with the four possible combinations of C2/caching settings and guess what ? 4 different results after wav compare with EAC ... all right, the differences are somewhat marginal cause the maximum sample value difference shown in sound forge is about 2500 (maybe 9 wrong bits or so ...), but I doubt that this particular drive is suited for DAE very well ... I will compare its ripping results with my other drives (my Plex is sooo slow on ripping this disc) during the next week so I can see which read mode is the correct one for the Toshi SD-M 1612 ...

Hello,

did some tests with my Toshi 1612 and the ONLY combination of settings that yields good results (same CRC on test & copy) is:
'has Accurate Stream feature' ON
'caches audio data' ON
'retrieves C2 info" OFF

Can be pretty damn slow on scratched CDs, though.

Absolutely right ... in the meantime I've been testing this drive with Feurio and EAC ... guess what: Feurio reports this drive to cache audio data (3 sectors) ...

I did some tests with my Toshiba 1712.
Same problem ...

Plextors have been reported to have perfect C2 with Plextools only, not with EAC.

The generic C2 reporting was perfect for an Asus and a Sony drive, but they were not tested under any conditions of error correction. http://www.digital-inn.de/exact-audio-copy-english/17426-asus-sony-perfect-c2.html

Hi Pio2001,

Sorry, but I don't clearly understand what do you mean by "not tested under any conditions of error correction".

Do you mean that the ASUS and SONY drives could have less C2 reporting accuracy if the test discs were only lightly scratched?

In other words, could it be possible that these two drives have perfect C2 reporting accuracy with severely scratched discs but bad C2 reporting accuracy with lightly scratched discs?

If that's true, it would be shocking!

Ciao.

It the other way, of course : they might have imperfect C2 if there were more errors.
According to the EAC graphs for the Asus (http://www.cdr-info.com/Sections/Art...D%2DRW&index=2), published at CDRinfo, the green part never crossed the 8th line, that is less than 3000 errors per second. Nero CD Speed graph shows less that 3500 errors, although I don't know if they are errors per second, in samples or bytes.
For Sony (http://www.cdr-info.com/Sections/Art...p+Vol1&index=3), the CD Speed graph is similar : less than 3500 errors (per second ?).

The error rate can grow up to 88200 per second in EAC graphs, and should go up to 176400 in Nero CD speed (C2 errors per second, 4 bytes per sample).

Now look at the sony DDU1621 behaviour :


C2 accuracy on random errors, in %, of the Sony DDU1621 firmware S1.6 DVD ROM drive, versus error rate in mono samples

This was obtained in the tests described here : http://perso.numericable.fr/laguill2/dae/dae.htm

You can see that the C2 accuracy of this drive is OK (99.3 %, see the C2 accuracy analysis part ) until about 25000 errors per second in mono samples, and then collapses completely, until missing nearly every other error at 88200 mono samples per second.

Those high error rate can occur as soon as one single scratch appear on the CD, if it it parallel to the groove (making the CD skip).

Hi Pio2001,

Thank you for the explanation.

Then it's safe to assume that those two drives will never fail to report a C2 error on slightly scratched CDs?

I'm not very worried about poor C2 reporting accuracy with badly scratched CDs (those are easily spotted). But I hate it when a drive reports that there were no C2 errors when in fact those errors really occurred!!

Best regards.
Ciao.