Film-Tech Forum ARCHIVE: DTS Disk Problems (Specifically)...WHY?

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Posted by Paul G. Thompson (Member # 655) on 04-06-2003, 01:27 AM:

Maybe it is just me, or our DTS equipment. We sure seem to get alot of bad disks lately.

Recently, I addressed what I thought was a DTS disk issue, thinking our DTS-6D was going on the fritz. When I went to one of our theatres, I discovered there was (supposedly) three sets of DTS disks from three different movies that were bad. The latest was of the movie "Chicago" disk 2 did not play in drive B, but it played OK in the other drives some of the time. The print and disks were circuited from one of our other theatres where it ran just fine in the DTS-6AD.

The disks do not appear to have any scratches or smudges from finger prints. The disks looked like new! But they didn't want to play. The DTS-6D has the latest firmware installed.

We received a new movie to play in the DTS house, and for the last two days, there has been no problems whatsoever.

WTF is going on here? Personally, I am getting tired of making "wild goose chases" to try to figure out what is going on.

Has anyone else experienced this problem?

Posted by Brad Miller (Member # 2) on 04-06-2003, 01:59 AM:

Yes it has become a serious issue for us, but has only been really plaguing the discs since about the time of the switch to the super thin plastic case. Try my trick on performing a test dupe before you use the discs that I posted a day or two ago. It lets you positively identify defective discs before you ever put them into the machine.

Posted by Per Hauberg (Member # 529) on 04-06-2003, 04:44 AM:

Is this a warning what to expect, when not just the sound, but the whole film comes on discs ?
I have no problem telling the audience to please wait a couple of minutes, till we have found a shovel to get the film up on the platter again, but as Poul said "wild geese" are not fun - to solve a problem in a hurry calls for visible problems. May digital pictures stay away from here until i retire...

Per

Posted by Michael Schaffer (Member # 1204) on 04-06-2003, 06:44 AM:

If you have the dts setup disc, you can easily check if the drive is OK. The disc plays without timecode and starts automatically after a few moments.

Posted by John Hawkinson (Member # 1135) on 04-06-2003, 12:17 PM:

Michael, CDROM failures are not binary. There are a lot of threshold effects, where a drive that's slightly off may play some discs and not others, depending on how dirty the lens is, how dirty the disc is, position of the data on the disc, etc.

You're much better off using a Brad's method of a known-good-disc, as it removes some uncertainty (of course, it is more work).

Also, every booth with a DTS-6D should have a lens cleaning CD (stick it in and the disc spins and the brush cleans the lens), and use it every few months, or if you see a disc problem. (The DTS-6 caddy drives have built-in lens brushes so don't need this.)

--jhawk

Posted by Steve Guttag (Member # 268) on 04-06-2003, 12:23 PM:

Actually Paul, I was going to suggest what John just mentioned...try a CD-ROM cleaning CD to brush off your lenses to get the drive the best possible chance of reading. One thing about digital...you don't know how close you are to cliff before you go over....just that it works or it doesn't. So, it is best to try and step a little farther away from it.

Steve

Posted by David Stambaugh (Member # 1102) on 04-06-2003, 12:23 PM:

What jhawk said. This sounds like the discs are being mastered slightly "off", and/or dirty readers in the field. Excuse my ignorance, but are DTS discs pressed, or burned (like CD-Rs)? If there's a problem mastering or burning the discs at the source end, it can cause all kinds of weird compatibility problems in the field.

Posted by John Hawkinson (Member # 1135) on 04-06-2003, 12:27 PM:

DTS CDs are pressed. (Of course, one can see the occasional CDR on a workprint,small independant release, student film, or somesuch).

Tangentially: I don't believe there's any evidence to suggest a disc mastering problem, David. (If I were Karen, I might be upset at your suggesting that's the case... we shouldn't impugn DTS or TES's quality control without a bit more solid fact.)

--jhawk

Posted by David Stambaugh (Member # 1102) on 04-06-2003, 12:33 PM:

Karen: No need to be mad at me. [Wink]

I was merely suggesting that if there's a "rash" of disc compatibility problems, it could be the mastering. We're dealing with a small sample here though, so I would agree that the problem is more likely at the booth end, rather than with the mastering. Assuming DTS is not receiving an unusual number of complaints about this anyway. Quality control on pressed discs is usually very high. CD-Rs can be more troublesome.

Posted by Don Bruechert (Member # 1538) on 04-06-2003, 01:08 PM:

Paul, I realize you have been at this a helluva lot longer than I have, but I'm gonna state that which is painfully obvious, just in case.... Have you been a good little boy and dusted the lens on your DTS timecode reader with a dry Q-tip?? Karen, if it is absolute taboo to do this, feel free to reprimand me, but I was taught to do it every time we change a film in the house as a general PM procedure. I would imagine that any kind of buildup on that lens could be a possible source of a mis-read just as much as could then lens in the actual DTS player (we also use a CD lens cleaner in there on occasion).

Just a suggestion of something to try.

Posted by Scott Norwood (Member # 30) on 04-06-2003, 01:15 PM:

I haven't seen these issues. I seriously doubt that there is a disk mastering/pressing problem. I'm willing to bet that it's either a maintenance issue (dirty lenses in drives) or older drives which are failing. The rare CDR disks are usually high-quality (Taiyo Yuden or Mitsumi or some other decent brand) disks and I've not had any issues with them, either.

One theatre where I fill in fairly regularly had a DTS unit in their big house which, until relatively recently, would not fault to the optical track if something went wrong with the digital system once format 10 was selected on the CP200. (This was an installation problem, not a DTS problem.) Anyway, we ran this way for over a year and never had a problem with DTS faulting. Trailers and other pre-feature material were run in SR.

All three digital systems have weaknesses, but DTS seems to have been the most reliable once the bad-drive problem was sorted out.

Posted by Paul G. Thompson (Member # 655) on 04-06-2003, 03:27 PM:

Brad, I found that and this time I am going to print it out. I forgot to do that when I orginally read it. I will definately try it.

For information for the rest, Brad's comment was in "The unexplained in DTS" Thread in FHF.

Don, I did look at that issue at the time, and everything seemed to be squeeky clean.

I also questioned the lazer cleanliness if the drive itself, and it was mentioned that won't usually happen. However, as Scott pointed out, maybe it did. At this time, it is worth looking into.

Posted by Bill Langfield (Member # 818) on 04-06-2003, 03:48 PM:

Opps...

Now I'm getting worried.

Of the places I work at, we have been slowly been working back
to DTS, mainly because of basement Dolbly readers MUST suck, and that from I've read HERE and else where DTS is better, not that I can really tell the difference.

But now to hear DTS discs are not working so well is a worry.
(perhaps it is not our player/CP after all causing our faults)

This really gets worse when you have to sit through 3 hours of midnight testing of Titanic or Baraka in 70mm (which are DTS only - Is MAG now gone?) to make sure the sound is going to stay on.

I don't know if this good or bad, but now we are going to run the Baraka sessions with a new print in 35mm rather than 70mm.

Erm, I'm not sure what my point was sorry!!

Bill!

Posted by Gordon McLeod (Member # 33) on 04-06-2003, 07:05 PM:

Never really had a bad disk problem as a common complaint usually adirty or old drive was at fault

Posted by Andrew Duggan (Member # 1302) on 04-06-2003, 11:23 PM:

Yes, bad DTS disks have been few and far between for us, with only one incident in recent memory. (Good thing, too because the optical soundhead in our DTS house is in dire need of some good old TLC that I haven't been able to get around to yet...) Any DTS problems we've had, more often than not, have been with dirty lenses in the drives. Thankfully the CD player for our non-sync is in the same sound rack as our DTS unit, so it's easy to keep a lens cleaning CD on hand.

Posted by John Hawkinson (Member # 1135) on 04-07-2003, 12:21 AM:

Don:

DTS explicitly recommends you only clean the timecode reader with compressed air (see the manual). That said, a Q-tip (tm) is unlikely to cause severe trauma, but it is not recommended.

Further, it's clear in this case that it is not a TC reader problem, as Paul has indicated that it plays fine in some drives, but not in other drives. Presumably, also, he would see the TC light transitioning. Remember that the DTS box will freewheel in the absence of TC for 4 seconds, so it has to be really broken, not just marginal (i.e. no fear of microtransitions you would not be able to observe in the LED).

--jhawk

Posted by Paul G. Thompson (Member # 655) on 04-07-2003, 01:56 AM:

I guess I'll get a gallon of WD-40 and a bucket of MEK and Acetone and wash 'em up. That should do it..... [Big Grin]

Posted by Leo Enticknap (Member # 534) on 04-07-2003, 02:27 AM:

Nah... just get one of those high-pressure home car wash machines and stick the pump input pipe into a 20-gallon drum of Renovex. That should do it! [evil]

Posted by John Hawkinson (Member # 1135) on 04-07-2003, 08:29 AM:

Wait...you have a 20 gallon drum of Renovex(tm), Leo? Don't waste it!. You can't make that stuff anymore, we need every drop!

--jhawk

Posted by Daryl C. W. O'Shea (Member # 1303) on 04-07-2003, 08:46 AM:

BTW, the Renovex trademark was cancelled on October 5, 2002.

Posted by Paul Konen (Member # 41) on 04-07-2003, 09:50 AM:

I have had problems with disk too and if I put in a different set of disks (from the other print) then they work correctly and don't lock up the machine.

Posted by Karen Hultgren (Member # 395) on 04-07-2003, 07:13 PM:

As mentioned before in other threads, please let me know when you get "bad" discs. I would like to see them and I'll send you replacments. All you need to is call or email me. I'm not hard to find.

Karen at DTS
khultgren@dtsonline.com

Posted by Brad Miller (Member # 2) on 04-07-2003, 08:15 PM:

Karen, did you get those two bad discs for Old School I sent? I am curious to what caused the problem (if you know).

Posted by Karen Hultgren (Member # 395) on 04-08-2003, 01:29 PM:

Hi Brad,

Yes, I got them and we are looking at them. No word back from QC yet. Thanks so much for sending them!

Karen at DTS
khultgren@dtsonline.com

Posted by Jack Ondracek (Member # 1466) on 04-08-2003, 01:59 PM:

This whole thread is pretty curious to me... mainly because we've had zero problems with our 6D. The issues surrounding CD cases, dirty drives, etc. are hard to evaluate because we've had no problems whatever... even on pictures that have been mentioned here lately.

Maybe we're just getting the best discs because we're so close to the depot! [evil]

(Sorry, Paul!)