Film-Tech Forum ARCHIVE: DTS starts mute

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Posted by Antonio Marcheselli (Member # 373) on 05-24-2002, 02:29 PM:

Hi everyone.

Something strange is happening on my system. I believe to know where is the problem but I would like to have your opinions too!

This is the situation: after the last DD trailer, I have the DTS Flying disk trailer. I see the "timecode" led tuning on, after few moments the "CDrom" and "Digital" turn on, CP500 selcts SK5 (Format 11).

The trailer starts with NO sound in the theater (and CP is still on SK5, and DTS units is reading normally).

It has happened twice. First time I thought that something wrong was happened with DTS and I turned off it for that show.

Today when the show went mute I selected immediately a Format 05 to have sound in the theater but I tried to come back to Format 11 at the end of the DTS trailer. The sound was there, no problem.

Since during DTS trailer all leds are lighted and SYSTEM blinking, and CD-ROM reading, I believe that the problem is in the CP500. Someone remember that I have some interferences problems with my CP500 that stuck the Video selector in the CP at changeovers.

I believe that now this is causing problems with format 11 too.

Any suggestions?

Bye
Antonio

Posted by Steve Kraus (Member # 476) on 05-24-2002, 03:10 PM:

I can only offer a related anecdote where I started a show and the DTS-6 kicked in, switching the CP500D over to Format 11 and from the looks of the indicators appeared to play but there was no sound. No way to tell if it was DTS problem or a CP problem and naturally it was not repeatable and it hasn't happened since. (I've toyed with the idea of adding some signal presence indicators to the output lines of the DTS in case it ever happens again.)

Posted by Antonio Marcheselli (Member # 373) on 05-24-2002, 04:51 PM:

Has happened again. This time I just switch between Format 11-Format 10 and immediately Format 11 again. IN the meantime I was projecting the same print, the DTS logo.

The sound reappeared when I select Format 11. It is definively the CP that kick but doesn't kick...

Few weeks ago I found that to cut off the interferences I have to remove the phoenix sound output of the CP..

Any other anectodes? Everything can help!

Bye
Antonio

Posted by Karen Hultgren (Member # 395) on 05-24-2002, 06:46 PM:

Antonio,

Use the DTS setup disc to check that the system is working correctly - that Format 11 is automatically selected by the DTS player and that sound is heard (from the player while the CP500 is in Format 11).

If no sound heard in Format 11 while the DTS player is playing in digital, then check the audio cable from the DTS to the CP500. Be sure it is plugged in - all the way down on both ends. If the cable is plugged in then use a meter to check for sound output from the DTS player. It should be at around 300mV RMS.

Karen at DTS
khultgren@dtsonline.com

Posted by Antonio Marcheselli (Member # 373) on 05-25-2002, 03:55 AM:

Karen,

I tried yesterday night, at the end of the show.
I use the film itself, starting and stopping them (covering or not the timecode) several times.
The player selected correctly Format 11 and sound was normal on CP.

It is definitively an RF interference, but now is annoying... From this time forward I'll have to check ALL DTS show start for sound.
I've already had to check for Dolby Digital to see if was started...

Then they call them "automatic booth"...

Thanks for your help, and if anyone has other suggestions...

Bye
Antonio

Posted by Gordon McLeod (Member # 33) on 05-25-2002, 09:29 AM:

Is your processor and dts etc got a star washer under the screws holdinh the chassis to the rack.
Also on the CP500 backplane there should be a jumper placed between the ground pushon connector and one of the earth terminals on the phoneix connectors
Interference is usually related to bad grounding practices

Posted by Antonio Marcheselli (Member # 373) on 05-25-2002, 01:42 PM:

Gordon,

Thanks for your help but we have already check the ground of our system. The problem is that we have a radio transmitter near the theater.

However, Perhaps this time is not an interference problem.

Before DTS logo I have, as Fox requested with Fax, Mail, sheet and more two Dolby Digital trailer: 007 and Minority report.

Is it possible that exactly when the DTS try to select the format Dolby try to drop to SR. I wonder this because today I had the same mute at the start of the first show; at the start of the second show I set SR (without auto digital) for that two trailers and DTS started normally.

I'll let you know.

Bye
Antonio

Posted by Manny Knowles (Member # 1171) on 05-25-2002, 02:06 PM:

Have you tried running the show with Dolby Digital disabled?

If you're using a Cat. 699, 700 or 701 penthouse reader, turn off the Dolby Digital reader and test out what happens if you use DTS as the only digital sound.

------------------

~Manny.

Now...where was I ?
Leonard Shelby, MEMENTO.

Posted by Antonio Marcheselli (Member # 373) on 05-25-2002, 04:46 PM:

Manny,

I can't disable Dolby Digital, but latest shows seems to start correctly just selecting, few seconds before of DTS logo, a Format 5 instead of leaving the 10 until DTS starts.

I'll add a piece of black leader (without DD) tomorrow to have Dolby Digital dropped BEFORE dts try to start.

Usually I have a black leader before the sound logo, this time, due to Fox requests, I have a DD trailer. Perhaps this is why it never happened before.

However: in two different theater we had a similar problem with DTS due to DD before DTS.
I didn't know, from this time forward I'll have a black leader before every DTS show.

Is it a common issue?

Bye
Antonio

Posted by Manny Knowles (Member # 1171) on 05-25-2002, 05:20 PM:

Yes, that's what I was eventually getting at. I think you'll have it solved by doing it that way. Let us know if the black leader solves the problem. I'm curious.

------------------
~Manny.

Some people can read "War and Peace" and come away thinking it's a simple adventure story while I, on the other hand, can read the ingredients on a chewing gum wrapper and unlock the secrets of the universe.

-- Lex Luthor, "Superman: The Movie"

Posted by Gordon McLeod (Member # 33) on 05-25-2002, 09:41 PM:

I have installed some CP500's in some tough enviroments for RF with no interferance.
Infact the RF shielding in the CP500 is CE approved and as such a bit of a pain

Posted by Antonio Marcheselli (Member # 373) on 05-31-2002, 01:57 PM:

Manny,

The problem disappeared after I splice an SR leader between last DD trailer and DTS logo.

Bye
Antonio