This is topic DTS 6AD (problems) slow & out of sync sound in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Ben Wales (Member # 92) on 05-05-2000, 03:53 PM:
We have been playing a 30min 70mm DTS timecode film. On two recent occasions half way through the film, the sound track on the CD-ROM soundtrack in the DTS 6AD Proccesor slows down and drifts in and out of sync as if played with a Analogue soundtrack the projector has been slowed down to about 20fps, the only way we can cure this has been to completly re-boot the DTS 6AD and it works the rest of the day with out any further problems.The DTS 6AD software has been upgraded with recent software to version 1.03, but the problem still exists, is this a problem with the DTS DSP or some other software problem?
Posted by Karen Hultgren (Member # 395) on 05-05-2000, 06:23 PM:
Hello Ben,When film is running, be sure the timecode light is on solid and not blinking. An occasional blink is OK but if it blinks a lot, then there is a problem. Usually, a blinking timecode light means bad back tension. This is easily checked by using your finger to gently press on the film as it enters the reader (do this while film is running). Another possibility is that the projector chassis is not grounded. Be sure to use an ohm meter to verify continuity.
Please ltell me know the name of the show. If this is a "special venue" show, there could be other reasons causing sync problems.
Be sure visit our web site at www.dtsonline.com for technical info on cinema products and to leave messages with 'cinematech' (my aka) when reporting problems. I always answer by the next business day and this way you'll be sure to be "heard" by DTS.
Please reply to me either here or at my DTS email address: khultgren@dtsonline.com
Thanks, Karen at DTS
Posted by Martin Frandsen (Member # 74) on 05-06-2000, 03:24 AM:
Hi Ben,Is it ''Blackadder Back & Forth'' you are currently running at the Millenium Dome in London? BTW will love to see those Pictures of the cinemeccanica's running 70mm 
Hope Dts can help you, i'll visit the ''Dome'' next time in London.
------------------
It's the new small talk. You do it so awfully well! - My Fair Lady
Posted by Ben Wales (Member # 92) on 05-06-2000, 08:43 AM:
Hello Karen,
The venue in question is Skyscape part of the Millennium Dome in London, it has only happen in one Theatre, So far I can't detect any Timecode drop out,when this has happened. When it last happened last week, we try to trick the system by blocking timecode signal from the DTS head as if we had lost timecode and to see if it will reset, but it continues to run with a slow sound track etc, and the only way to cure is to reset the 6AD by turning it off and on.
Posted by Carl King (Member # 398) on 05-09-2000, 12:04 PM:
Hi BenI experienced similar problems quite some time ago. A blinking green light on the reader and a loss of digital sound. I solved the problem, with advise from another projectionist, by removing the sticker on the side of the reader to expose an adjustment screw (slotted). I turned the screw until I had a slolid green light on the reader. This apparently aligns the reader with the timecode. No problems since
Carl King
Posted by Karen Hultgren (Member # 395) on 05-09-2000, 12:38 PM:
Hello Ben,I will have Andy at our UK office give you a call so we can get your problem solved. Please feel free to call us at any time when problems occur. We want satisfied customers.
Karen at DTS
Posted by Manny Knowles (Member # 1171) on 02-19-2003, 10:19 PM:
We have a 35mm DTS-6 system that is running slow and "making funny noises" during playback.
What causes this?
Posted by Daryl C. W. O'Shea (Member # 1303) on 02-19-2003, 10:22 PM:
If the sound is 'slow' but is staying in sync (like a really messed up pitch change), and your projector is running at the proper speed (ie switching to analog sound sounds fine) I would try changing out the CPU board.
Posted by Antonio Marcheselli (Member # 373) on 02-20-2003, 03:04 AM:
Ben
I had a similar problem once. The sound was wowing in a very noticiable way.
Found out that the reader was on a plate that wasn't firmly connected to the projector and the plate itself was moving slightly. In this case the reader sees the film running at a speed that is always changing and the sound was wowing.
I then realized that our plates was mounted upside down...
I saw many cinemeccanica's with upside down plates... Check if yours are firmly screwed to the projector!
Bye
Antonio
Posted by Manny Knowles (Member # 1171) on 02-20-2003, 07:46 AM:
Thanks. I got that service request by phone so I'll go have a listen and also take a look around and see what's going on there.
Any more suggestions?
Posted by Michael Schaffer (Member # 1204) on 02-20-2003, 09:36 AM:
Not a suggestion, but a question. I have never experienced those problems with dts, but they are described here from time to time.
If the sound stays in sync, but the pitch drops, or the sound drifts out of sync, hoe does that come about? Obviously, a dts processor has to have a sample rate converter to match the the number of samples coming in per second to a defined output rate (probably 44,1kHz) or else, the sound would drift in pitch all the time or the unit wouldn`t work at 25fps either?
How is this achieved in the processor?
In another topic about measuring projector speed Karen mentioned that the rate at which timecode comes in is used to time the processor. Which part of the system does that and where exactly is it located?
Posted by Karen Hultgren (Member # 395) on 02-20-2003, 12:22 PM:
Manny,
If the sound track is slow in DTS then you have a timecode reading problem or you have old TCR firmware. Also, if your projector is ruuning off-speed, it will cause the sound to slow.
Check your projector speed. It should be running at 24fps +/- 5%. Note: It will run fine at 25fps, that is within tolerance.
See if the reader blinks a lot, if it does, it can cause the sound to "wow" or slow.
Look inside the DTS-6 player and see what version TCR chip you have. It's on the timecode card (one with the LEDs), D422 at U14. Tell me what the label says. Our curent version is V1.46.
If the reader does not blink and you have current TCR firmware, then you have a faulty D422 board and the player should come in for repair. If you decide to send it in, send me an email first. I'll need the serial number of the unit so that I can issue you a RMA and I'll need to know who your DTS dealer is.
Karen at DTS
khultgren@dtsonline.com
Posted by Michael Schaffer (Member # 1204) on 02-20-2003, 02:02 PM:
Can I also take that as an answer to my question?
Posted by Antonio Marcheselli (Member # 373) on 02-20-2003, 03:20 PM:
Karen,
on my installation the readers weren't blinking at all but the sound once started wowing!
But I do not remember if the TCR eeprom was changed before of after that problem.
Bye
Antonio
Posted by Karen Hultgren (Member # 395) on 02-20-2003, 03:52 PM:
ANTONIO = If the sound is wowing with a DTS-6D or a DTS-6, the reader's green light will blink unless it is a projector speed problem.
If it is on a DTS-6AD cinema processor, the reader may not blink. You MUST look at the edit count and projector speed.
MICHAEL = I answered part of your question but not all. The rest of your question (about proj speed) will be put on a fresh thread once I have time to do it.
Karen at DTS
khultgren@dtsonline.com
Karen at DTS
khultgren@dtsonline.com
[ 02-20-2003, 06:38 PM: Message edited by: Karen Hultgren ]
Posted by Michael Schaffer (Member # 1204) on 02-20-2003, 04:35 PM:
That would be very nice. I am very curious to learn at least in broader terms how the projector speed and sample rates are matched in dts.
Posted by Antonio Marcheselli (Member # 373) on 02-20-2003, 05:15 PM:
Karen,
Yes, since the reader was not firmly screwed to the projector, the reader itself saw the print AS the projector was changing its speed continuously...
Bye
Antonio