Film-Tech Forum ARCHIVE: DSTR Reading 1's and 0's

This is topic DSTR Reading 1's and 0's in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Robert Schultz (Member # 2301) on 03-17-2004, 03:11 PM:

I have installed a number of DSTR units recently and I have been noticing that we are getting 1's and 0's on prints that are 2-3 weeks old. I have never seen these numbers on a Cat. 701 or Cat. 702 right out of the box. I just wanted to know if anyone else was having the same experiences. Has anyone seen a consistent reading of 1's and 0's on either of the Dolby readers?

Posted by Mark Gulbrandsen (Member # 72) on 03-17-2004, 03:22 PM:

You will typically get at least a digit lower reading from the DSTR than with the cat 701. I can't speak for the CAT 702 as we only use the DSTR now because of its easy to replace LED and the fact that it tracks better than the others do. I can say that the CAT 702 has the same technology as the DSTR so in theory it should be comparable in error readings to the DSTR.

Mark @ CLACO

Posted by Ken Lackner (Member # 1002) on 03-17-2004, 03:52 PM:

Um....out of pure curiosity, what's a DSTR??

Posted by Daryl C. W. O'Shea (Member # 1303) on 03-17-2004, 03:59 PM:

http://www.bacpinc.com/readersdigital.htm

Posted by Robert Schultz (Member # 2301) on 03-17-2004, 04:04 PM:

http://www.uslinc.com/products/dstr-20.htm

Posted by Mike Babb (Member # 1379) on 03-17-2004, 06:40 PM:

Hi Rob...I may have mentioned this when we met but for everyone else...I installed 4 of them and was getting 3-4 error rate. I'm unsure of the age of the prints but being in medium size houses I'd imagine 3+ weeks or so. I think a big factor here is they are sitting on Christies and jitter is high. Also interesting to note, they gave these readings out of the box and my tweaking might have improved some tracking details but the overall error rate stayed pretty much the same.

Posted by Robert Schultz (Member # 2301) on 03-17-2004, 08:08 PM:

Mike...have you ever gone back to those same houses to see what kind of error rates you were getting with different prints? I have seen some prints that just don't get any better then a 3 or 4, but I've never even seen a 1 (let alone a 0) on a Cat. 701 or Cat. 702 no matter what print was playing. Now my experience with the Cat. 702 is limited, but the Cat. 702 readers that I have seen in service were not getting 0's and 1's...EVER. Are the labs getting better and the Cat. 702 is also reading 1's and 0's or is the DSTR better at reading the patch?

Posted by Mike Babb (Member # 1379) on 03-17-2004, 08:36 PM:

I haven't gone back to these, but I've been working in this place installing 4 screens so I may look them over if I have a little time. I'd like to try that alignment loop they gave us on them.
I think the best I've seen on a 699/700 is 2-3 on a consistent basis. You can get it lower if you tweak it to the print but it can change reel to reel. I know people say they get lower consistently but I haven't seen it. Plus the way it changes trailer to trailer and reel to reel makes me wonder how much it is worth sweating over.

What kind of heads were the ones you just installed sitting on?

Posted by Mark Gulbrandsen (Member # 72) on 03-17-2004, 09:26 PM:

Guys, There is new technology in the DSTR developed by BACP that was also shared with Dolby for use in the CAT 702..... They ought to read about the same error rate in theory.

Mark @ CLACO

Posted by Robert Schultz (Member # 2301) on 03-17-2004, 10:04 PM:

I understand the new technology used on the DSTR. This is why I have been using them for installations. Every installation I have done has been on a Simplex or Century projector. Knowing that the DSTR and Cat. 702 are using the same advances in reader technology, the question remains...

Has ANYONE seen 1's and 0's on a Cat. 702?
Is anyone else getting 1's and 0's on their DSTR?

Posted by Brad Miller (Member # 2) on 03-17-2004, 10:39 PM:

Yes, I see 0s and 1s frequently on my cat702s. I have also seen those numbers from time to time on my cat701s (although as a general rule the 701 is the worst tracking of all the penthouses out there and will commonly run between 1-3). The problem is a matter or dirt and abrasion. The SRD tracks get quite a beating in most projector gates. Also the tiniest amount of dirt will wreak havoc on the reader's ability to read the track. If you have any dirt left over at the end of the show's run in the gate, you are slowly damaging that SRD track, especially if you have hardened deposits on the bands/rails. Get yourself a media film cleaner and a bottle of FilmGuard and you will see the initial error rating on even a brand new print will DROP and will never rise. If you want to see true performance out of any of those readers, ya gotta keep the films perfectly clean.

Posted by Dean Kollet (Member # 1789) on 03-17-2004, 11:28 PM:

Brad,

What can I do with 700's that read a 4-6 all the time?

Posted by Daryl C. W. O'Shea (Member # 1303) on 03-17-2004, 11:31 PM:

Turn the LED power trim pot up very slightly. If you're allowed to do that without being shot.

Posted by Dean Kollet (Member # 1789) on 03-17-2004, 11:32 PM:

it's not led though...

Posted by Daryl C. W. O'Shea (Member # 1303) on 03-17-2004, 11:33 PM:

Yeah, I'd guess you would have a problem if you've got a LED array in a 700. How old is the lamp? Do you have a scope?

I'm going to bed.

Posted by Dean Kollet (Member # 1789) on 03-17-2004, 11:37 PM:

yeah. kinda. but the question is, the sound plays perfectly with 4-6's but does that take out anything of the sound quality?

Posted by Daryl C. W. O'Shea (Member # 1303) on 03-17-2004, 11:42 PM:

So long as it's not dropping below 6 and failing, most anyone you find won't be able to tell that the processor is guessing to cover the errors.

Posted by Robert Schultz (Member # 2301) on 03-18-2004, 12:01 AM:

Dean...1st - check the lamp. If you haven't changed your lamp is quite some time then you may get everything working good again with a simple lamp change. If your lamp is in good shape and you are still getting poor readings then you need to do a complete alignment on this unit. If you are familiar with working a dual trace oscilloscope and you are mechanically inclined enough to work on projectors then you will have no problem following the alignment procedure for any Dolby reader. You will need to use a new loop of test film and preferrably have a computer hooked up with the DRAS software so that you can also see your alignment results in the Dolby software. Using the oscilloscope along with a laptop and the DRAS software makes the alignment procedure very nice.

Also...Dolby has found that every piece of test film seems to have some error in the patch alignment on the film. There is a new alignment film called QC10 (CatNo.530). This film has an offset for the lateral, vertical, and azimuth adjustments that 'in theory' will set your reader to 'perfect'. If you use these offsets in your alignment with DRAS then you should always be well within the tolerance of any film that is printed as 'acceptable' but not perfect.

Posted by Daryl C. W. O'Shea (Member # 1303) on 03-18-2004, 12:13 AM:

I prefer to just use a few of the most average trailers I can find and align accordingly to them. Afterall, you don't show the audience test loops. [Smile]

Although the QC'd test loops sound interesting.

Posted by Sam D. Chavez (Member # 1841) on 03-18-2004, 12:51 AM:

Thank you all for the good press.

Not to be too modest, but I just did the Fearless Tales Film Festival with loaned equipment from Dolby, including new 2 Cat. 701's. I was getting 1 and 2 with an occasional 0 on a new print of "Tool Box Wars, a new Tobe Hooper film. These readers were on top of 2 Super Simplex's mounted on an RCA 9030's with arc lamps no less.

Lonny and I were kidding that there were probably only three prints of the movie in existence so they better be good.

The print quality as regards SR.D is definitely getting better.

I saw an earlier post about readers on top of Christies having higher error rates because of jitter. The Christie projector with a penthouse reader reads very well in my experience as there is no particular jitter caused by the incoming sprocket. The optical sond head is another matter entirely of course as there is nothing but jitter.

Posted by Brad Miller (Member # 2) on 03-18-2004, 12:56 AM:

The Christie projector gate is one of the more abrasive gates out there. As such if you were to run a movie through it 100 times vs something like a Kinoton or Cinemeccanica, you would find the error rating would have increased by a point or two over that time frame. It's definitely not jitter related, it's the abrasiveness like I mentioned in my post above. In fact if you take notes on the error reading of each reel, you will see that as each reel passes, the damage gets worse (assuming that platters are being used). This is why it is common to hear reports of "the digital track wearing off" after only a few weeks of running. Anyone doubting me, run the test for yourself. This is assuming of course that you are just running the film without cleaning, or through either dry media or PTRs for cleaning.

Posted by Mark Gulbrandsen (Member # 72) on 03-18-2004, 09:13 AM:

"The print quality as regards SR.D is definitely getting better."

Well, I wish I could agree with you on that regarding my service area. We still reaglarly get prints that won't play right out of the can, and some that ahve just bad reels. The worst I have seen it was last November to the end of this past January where this was getting to be a very common occurance....

Because this problem has been so on going, several of our bigger customers have asked us to switch over completely to DTS on their new projects they have started because they have far fewer playback problems with that format.

Mark @ CLACO

Posted by Brad Miller (Member # 2) on 03-18-2004, 02:23 PM:

I can't agree with you there Mark. DTS seems to continue to have lots of issues, but the worst problem of all is those new stupid dvd-type of cases they are shipping the discs out in! [Mad]

It's getting ridiculous, easily 25% of the discs I get are scratched up because the cases opened during transport and get badly scratched, or they come in flat out broken. You can't play a broken disc.

Maybe the local depot here doesn't know how to pack the cans, but I see it from prints via TES too. I fail to see how prints going to Utah would have SRD tracking problems and yet there be no issues in Texas. I would look more for a tinkerer in your booths or lousy projectionists in general as the source of your problems.