Film-Tech Forum ARCHIVE: Sound lockout on CP-500

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Posted by Jason Black (Member # 684) on 12-20-2000, 06:09 PM:

I have a perpplexing problem with one of my CP500's. Let me see if I can explain it so that you can understand it...

The trailers (most of which are timecoded with DTS or SR-D) will play through fine in the SR-D format.

*IF* the print is a quad print and it has an attached trailer that is also has the DTS timecode, the CP-500 will lose all sound as soon as the DTS timecode/processor sync begins on the trailer. This occurs ONLY when the DTS dics are in the drives. The CP500 shows that it is in external 6 track (forget the #, but it's the upper right format) but no sound is present from either the monitor OR in the house itself.

It is a DTS 6D with 3 drive bays but we no longer get the trailer discs, which is stupid because we FINALLY have the ability to ustilize them, so there are no trailer dics cuasing any problem. The sound loss is not specific to either of the 3 drive bays.

My tech says it's going to be a card switching deal but I'd like to know where to start looking as far as cards go. This problem, BTW, does NOT oocur if the DTS unit is switched OFF, which is the way we normally leave it. Most prints are SR-D anyway, but I hate to have a $7500 piece of equipment sitting there collecting dust.

Any replies will be greatly appreciated!

Thanks and Happy Holidays...

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The early bird may get the worm, but the second mouse gets the cheese!

Posted by Brad Miller (Member # 2) on 12-20-2000, 06:24 PM:

Dumb question, but is the AUDIO cable connected from the DTS player into the CP500? Sure sounds like it has come loose.

Posted by Jason Black (Member # 684) on 12-20-2000, 08:24 PM:

Brad,

Yes, the audio cable is firmly connected. I should have added that we can revert the processor back into SR-D and BACK into external digital (DTS) and the sound reappears. This tells me that it is ultimately what seems to be a "switching" problem, for lack of a better term. Once we finally get it into external digital (DTS) it plays fine. Only when it detects the attached trailer or feature (when there is no attached trailer) does it drop sound totally. As if when the processor senses DTS and tried to switch it into DTS, it fails miserably, but it switches into SR-D without fail EVERY time. One more reason I prefer SR-D over DTS...

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The early bird may get the worm, but the second mouse gets the cheese!

Posted by Brad Miller (Member # 2) on 12-20-2000, 10:07 PM:

Do you have another DTS player you could swap into this auditorium to see how it behaves? Perhaps change out the DTS logic board as well. One way or another, unless someone else here has come up with this problem and knows of a solution, you're going to have to start troubleshooting a little bit. I've never had such a problem, so it's all speculation from my end.

Anyone out there have this happen before?

Posted by Randy Stankey (Member # 64) on 12-20-2000, 10:12 PM:

I've always been of the mind that if you have two or more digital players in a sound system that you should turn off the one(s) that you aren't using.

I've had instances where the SDDS and DTS will get into a "fight" if they are both on. This creates a kind of "echo" effect. Maybe that's the Ultra*Stereo processor but I just shut the unused player off and avoid all that crap.

Posted by Paul G. Thompson (Member # 655) on 12-20-2000, 10:31 PM:

What surprises me is that the DTS is not switching the CP-500 into SRA when it defaults. And, another thing that surprises me is when the DTS defaults, and then comes back after finding the correct time code to match whatever is playing, why the outputs of the DTS appear to be dead until the CP-500 is switched out of format 11 and then back into format 11? This is a new one on me....

Randy - you have something noteworthy there.

Posted by Adam Martin (Member # 641) on 12-21-2000, 12:52 AM:

Is it trying to switch into the correct format? If the automation breakout board isn't the one for the CP500, it could be pulsing the wrong format.

Posted by Jason Black (Member # 684) on 12-21-2000, 07:34 AM:

The unit switches to the correct format (11) when it senses the timecode for the tralier/feature, it just has no sound. NONE.
I can send it back to SR-D and there comes the sound. Then I can switch it to DTS (11) and there is sound again. From that point, it does not lose aound anymore for the entire show.

Busting my brain here...

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The early bird may get the worm, but the second mouse gets the cheese!

Posted by Paul G. Thompson (Member # 655) on 12-21-2000, 05:47 PM:

Jason, I think Randy's idea about the two processors getting into a electronic fight with each other may be causing the problem. When you have two Radio Frequency producing units sitting on top of each other, they could beat together and give you a third frequency that could drive other electronic circuits nuts, as well as the poor guy trying to figure out what is really happening.

Posted by Andrew Walls (Member # 179) on 12-22-2000, 11:06 AM:

Jason,

I bet if you push the Format 11 softkey again as soon as the sound fails, the sound will come back. I have found this happens in some cases with a DTS 6D and a CP500 system.
Why? You got me! Maybe someone from Dolby or DTS could read this and help out.

- Andrew

Posted by Jason Black (Member # 684) on 12-22-2000, 10:57 PM:

Andrew,

You are exactly correct. If the format 11 key is pressed as soon as we notice the loss, it picks right back up.. I'm still trying to find out what the problem is. Our tech is supposed to contact Lonnie Jennings at Dolby and see if he has any inside info to offer...

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The early bird may get the worm, but the second mouse gets the cheese!

Posted by David Miller (Member # 412) on 12-24-2000, 03:08 AM:

I disagree with the electronic battle between processors. I have (2) DTS-6D's hooked to a CP500 hooked to a DFP-D3000, which all runs through the Sound Web and have never had any problems of this type. Realizing that this is not quite like your set up, maybe the CP500 and the DTS fight with each other, but the DFP, the CP, and the DTS have never argued here.

At another theater I worked at the DTS was hooked into the CP500 as you have described and every once in a while the same problem would occur on attached trailers. I consulted our tech about the problem, but we were never able to come up with a solution. We tried switching DTS units, tried switching all of the cards in the CP500, and even went throught the automation wiring (we were using TA-10s). And on top of that the problem was intermittent so it was very hard to trace.

I know I have not presented a solution, but maybe the experience will help. Good luck.

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David Miller
millerdk@plu.edu
Projectionist, Seattle Cinerama