Film-Tech Forum ARCHIVE: DTS trailer soundtrack different from analog

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Posted by Steven J Hart (Member # 2340) on 10-27-2004, 07:28 AM:

I've noticed that many trailers are missing the music track when played through a DTS system with the trailer disk loaded in the machine. If I switch to the SR analog sound, the trailer's music track will be there along with the voice and Sfx tracks. I find this a little odd. Does adding music to the track require a lot of extra storage space on the DTS CD-ROM? Or is something else going on.

Posted by Steve Kraus (Member # 476) on 10-27-2004, 09:12 AM:

Anything is hypothetically possible but the sound should be substantially the same.

Are you sure you are listening to all channels when listening to DTS? Are you sure your DTS system is installed correctly and all channels set to the proper levels? Digital sound (all three types) can send sound independently to each channel without cross talk. Analog sound is a 2 channel system that uses phase and level to direct sound among 4 channels (5 with subwoofer) and cannot do so with 100% separation. If the original mix has music playing on L & R and you are only listening to C you won't hear it in digital but will hear it in analog.

Posted by John Hawkinson (Member # 1135) on 10-27-2004, 04:55 PM:

Similarly, the output gain on the DTS unit might be misconfigured.
Are you sure this does not happen on features? Can you give an example of a trailer where you see this problem, so someone else can verify?

--jhawk

Posted by Steven J Hart (Member # 2340) on 10-27-2004, 07:11 PM:

Thanks for your ideas. The DTS system was set up properly by a professional tech. Features sound great in the Auditorium. My theater is a single screen, so I can't try the same trailers in a different auditorium. We don't run film Thursdays, so I'll do some more experimentation with different trailers tommorow.

Posted by Brad Miller (Member # 2) on 10-27-2004, 07:46 PM:

Play a setup disc. (If you don't have one you can download an image file of one here.) Verify you hear each channel being called out. You could have a dead amp or something.

Posted by Joe Redifer (Member # 3) on 10-28-2004, 09:01 PM:

Are you listening to the trailers in the auditorium, or from your booth monitor? If you are listening from the booth monitor, you may only have the center channel selected to be heard. The music is probably playing in the left and right channels, but you don't hear them because those channels aren't selected. If it's like that in the auditorium, then you gotz somethin' screwed up somewherez, yo!

Posted by Steven J Hart (Member # 2340) on 10-30-2004, 12:38 PM:

Just checked out the booth monitor and found that the install tech had (for some unknown reason) wired the L,C,R inputs all from the feed from the center channel amp! I re-wired that part of the rack and trailers now play fine in the booth (and in the auditorium)

Brad, thanks for the link for the DTS D3S disk download. I burned a copy of it and used it to isolate the problem.

Thanks a lot for the ideas. If I would have just walked out into the auditorium while the trailers played I would have figured it out myself.