Film-Tech Forum ARCHIVE: Odd sound loss

This is topic Odd sound loss in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Dan Chilton (Member # 2288) on 03-08-2008, 05:53 PM:

We just started having a strange problem where dialog is mysteriously cutting in and out. I stood in the auditorium to assess the problem, and it was very odd -- music and background noises sounded fine, but the dialog was weak and crackly.

In the booth, the same problem was evident through the monitor. I checked all the inputs going into the processor, everything was fine. I traced the wires from the soundhead to the processor, checking for a problem, but again, everything seemed fine. The film was seated properly in the soundhead, and the red laser was in focus and aimed correctly.

As I was looking for the source of the problem, the sound came back on... I didn't do anything! 20 minutes later, it happened again. I opened the sound gate just a little and moved the film with my finger, to ensure it wasn't loose. That was fine. I moved the red laser back a little, then up a little. Didn't seem to affect it.

Finally I stopped the film and cleaned the cell and laser with a q-tip and lens cleaner. Started it back up, and it seems to be okay... for now. I'll continue monitoring it throughout the day, but in the meantime, has anyone had similar problems? Any ideas what may have caused this?

Posted by Gordon McLeod (Member # 33) on 03-08-2008, 06:11 PM:

Telling us the type of soundhead processor and amps would be helpfull

Posted by Dan Chilton (Member # 2288) on 03-08-2008, 06:17 PM:

Soundhead is Simplex SH-1k, Star/RS I believe. Amps are Strong TA 240 & 242. Speakers are set up in a center/surround configuration.

Posted by Scott Christopher (Member # 834) on 03-09-2008, 05:59 AM:

I'd start by swapping amps. Also check the speaker connections - I have had the speaker terminals slowly come loose in the past. I now make routine speaker terminal checks.

Posted by John Walsh (Member # 168) on 03-09-2008, 06:41 AM:

Does your monitor allow you to listen to either the amp inputs or the speaker output? If so, use it to see if the problem is occuring before or after the amps.

Posted by Sean McKinnon (Member # 612) on 03-09-2008, 09:48 AM:

What sound processor are you using?

Posted by James Westbrook (Member # 3690) on 03-09-2008, 05:00 PM:

The problem could be the center channel eq card needs it's contacts cleaned where it plugs into the processor OR the eq card needs replacing.