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Old 28th April 2016, 20:15   #7  |  Link
Ghitulescu
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Join Date: Mar 2009
Location: Germany
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Quote:
Originally Posted by Groucho2004 View Post
So, the quality scans I ran for years with my Plextor PX-B950SA and Sony BWU-500S (both re-badged Lite-on) were pointless?
The Plex is an LG IIRC, so it should be a good reader. One can see if it's a true Plextor by the eject button.
The Sony is indeed a LiteOn.

The results are not entirely wrong. Actually, the LiteOn can provide good results in terms of precision. It is OK to compare with the standards, keeping in mind that is only an approximation.

In other words - if you consistently use the Sony for checking up the quality (and only for quality - that is the reading properties stay as constant as possible) - you can build your own database with quality parameters. Keep in mind that the LiteOn is better than the average and thus the results may be better (less errors).


There are a few caveats - some drives do not provide all the parameters required for a full analysis. Sometimes not even a basic info like the jitter.
Also the way data is presented may differ from one manufacturer (or even model) to another and/or from the standards. For instance the Plextors made by LG are obviously different form the original Plextors. The reading speed is also of paramount importance. Foreseen was 1x for both. However, with some precautions, industrial testers may use higher speeds, like 2x or 4x. The errors are corrected by a certain factor. Some drives only give all infos at a particular speed, eg the Plextors should run at 1x or 2x (some also at 4x but no more).



However, instead of approximate values that might tell nothing, better is to do a WRITE/VERIFY and pay attention to the reading graph - it should approximate the reading curve of the drive - id est, the drive reads the CDR/DVDR with full speed (if there are errors, even small, the drive reduces the speed - one sees the graph falling and/or hears the noise changing).
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