Suggestions to QC your mastered discs

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Discussions on QC'ing master discs, and what equipment to use.

Originally Posted by Rich LePage

We have one of those expensive Clover QC systems and based on analysis using that, approach above still seems to produce least errors. A few of the newer drives, notably some Sony OEM units (which are actually Lite On, surprisingly) seem to dependably give few errors at higher speeds, but many others don't, though the error rates are fine for use as refs done high speed.

But, it's case by case. I have two identical model Sony OEM drives and one is very dependable while the other one isn't-- when swapped into same system.
Both run fine, but time and again, one produces higher error rates on discs than the other one. And that's at just about ANY speed, too. Many newer drives actually can do worse at very slow speeds than mid-range ones like about 8x. Each seems to have its own favorite sweet spot in the limited try and see testing I've done.

Also the Mitsui (now MAM-A) QC is just not what it used to be, I seem too often to have to reject burned masters for too many errors. Not willing to send them to a plant unless I can verify in 2 sep test passes that the error rates are very low. With the old burners especially, I run the gold media, seems to give best results and still have only ever had one master rejected by a plant for too many errors -- long ago, before we got the QC system.

Tried the Wavelab demo and liked it, might go with that in a few months. Adobe has a major new version of Audition, supposedly way different than the old Cool Edit Pro, so at some point will probably try both that and Wavelab and see which works better for typical needs here.

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More thoughts from Rich:

Originally Posted by Rich Lepage

Your experience in real world listening seems to run parallel to mine and also to what I have been seeing with the Clover QC unit. Yep, diff. media and diff speeds, burners and so on do sound different to me too.

But the gold seems to be about the "roundest wheel". The MAM-A silver, well the quality (listening and Clover testing) has been all over the map from lot to lot. Sometimes very good, but sometimes, really bad. Many of the same problems you mentioned, partic. collapse of the stereo image. The Taiyo Yuden media (80s only) has been more stable lately (testing both very subjectively and with the Clover too) so have been using that for both CDROM work and often for client refs too. So far, no one has kicked back a ref as not playable though it's an 80 min blank, so I guess most clients are using newer players. My car system (late 90s Jeep) will eject any 80 minute CD put into it, though it plays 74's fine.

I've had REALLY bad luck with the MAM 80 blanks though -- both silver and very surprisingly, the gold ones too. Not only do they subjectively not sound as good (same program, same burner) as the 74's but the Clover thing generally shows them to have many more errors. In fairness I think all I ever bought of the 80s was from one batch though. I usually buy from Media Supply in PA, a big MAM-A distributor.

The Clover unit is fairly cool for what it is - consists of a graded and modified Plextor drive (SCSI) which allows it to measure a big variety of error rates, and will even let you look at the pit geometry if you hook up a scope to it.
It requires a COMM port to run besides the SCSI card (they include an Adaptec controller), but will run on just about anything. I have it set up on an old DEC Pentium 200, one of a very few packaged computers I've ever owned bought as a closeout when Compaq bought DEC.

Clover's info claims that some of the errors it is measuring are likely causes of some of the same things you and I are hearing/seeing-- it measures much more in terms of errors than just BLER.

But like anything else, it is not totally empirical either-- since there are the variables of the computer host, also many others. You check to see that the thing is still calibrated fine and that all is well using 2 test discs they supply with it -- 1 known good (they give you the analysis of the disc when the unit was shipped) and one with def. known errors (they give you that analysis too). So far, our system seems very repeatable to the standards from when it was shipped (about 1.5 years ago). But seems the more bare bones the host machine, the better. I have it on a very simple Win98 system that is about as vanilla as you could have, no Internet etc either. I just use that computer for QC'ing, really nothing else except printing out the documentation.

That's also why I check masters twice with it-- the results always will differ, but only very slightly with a good master, and the results will be fairly close to the "standard" cal. disc when all is well. I print the results and ship with the masters too.

www.cloversystems.com if you are interested at all, but it isn't cheap, though about the cheapest thing beyond toy class that I could find when I was looking around. The owner apparently did some work way back for Dave and MTU in its very early days, though last time I spoke with Dave he didn't remember the guy -- that was some time ago however. They make a few different types of units, the one we have is called CDX.

Seen the same thing with DVDs used for data backups. No surprise that cheapo media is not reliable -- but the one brand that seems to work well time and again for those has been Verbatim. We have many DVD drives, from 4x to 16x, mostly use them for data backup which is always fully verified after writing (as a separate verify pass, using Backup Exec). The Verbatims seem to be very reliable, most others, not. Will have to see how they hold up over time as storage media-- but I did restore a project done a few years ago recently that was backed up to DVD and it worked out fine. With really critical stuff that is very likely to be reworked years later, I back up to both DVDs and DDS data Dats which is what I used before the DVDs, and usually run 2 sets of DVDs too just in case. I get paranoid that way!

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More thoughts...

Originally Posted by Rich LePage

What led to the Clover for me was (besides wanting to be able to know more
what was going on) that many clients had been seeing problems with stuff done by competitors, and so though it wasn't the case with stuff I did, I figured it was high time to be able to understand more why and also to be able to provide documentation of what was going on with masters when they left here. I've also got work because others produced CDs that plants rejected - sometimes several times. Also more routine things like whoever did the work had no concept of average and peak level in some cases!

The Clover guy told me he also has seen same variation situation with the MAM-A's in more recent times- says he's been using the Taiyos more with the duplicators they also build. Guess he offers short run duping services too.

I'm only "sold" on the Taiyos for the moment. I have a bunch on hand, along with a bunch of MAM-A silvers from diff batches. I try to pull about 25 pcs from each batch and hold them awhile just to have a benchmark, though I do that less with the golds since they've been good except for the 80s.
The older MAM-As are often more consistent from disc to disc than current
production, though that's a somewhat subjective call. Anything that still says Mitsui on it has been very consistent for most part.

Send the MAM-A guy's info whenever convenient and I'll inquire.

I've seen less variation in the packaged MAM-As than the bulk ones. For convenience, I buy some silvers in jewel cases in cartons of 25, and use those for cassette masters which get burned at higher speeds than CD masters, though usually just at 4 or 8x tops.

Have not tried the MAM-A DVD-R's in quite a while so will get M/Supply to send me a few next order. The Verbatims though have been great. Not so with cheapos like Optodisc and Ritek - as you'd expect.