This is topic Strange Sound Problem. in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.


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Posted by Carlos Villalpando (Member # 7411) on 10-21-2013, 08:49 PM:
 
Hi!
Last sunday I attended a 2D screening of Gravity at a local 12-plex.
It was on one of their bigger screens (50ft screen) and 5.1 sound.
We arrived, took our seats and waited, as usual. But when the show started there was something unusual.

A Sears commercial started playing and there was a strange problem with the sound. It was surrounds only... this commercial has a song in it (http://www.youtube.com/watch?v=Njw21HkDYN0 , in case you wanted to see it ) and you could only hear some music (in a very weak level) coming from the surrounds (and no lyrics).

I went to the auditorium entrance and told the employee about it, he called on the radio and told me they were "checking it".
When I came back to the auditorium I could see two employees at the booth looking at the projector. A loud popping sound came from the center speaker and then sound was back at the front. Just with one little detail... Center and surrounds only.. No side channels.

Once again I came to the auditorium entrance and told the employee about it, and when I came back in the auditorium I could see the two employees again through the booth window. No popping sound this time.. just suddenly side channels started sounding again. Luckily, this was fixed just before the last trailer played.

After those problems were fixed, the sound was very good with nice dynamic range.. the crescendo at the beggining gave me chills. There had been a long time since I heard a movie sound this good.

May be worth noting this is an all digital multiplex.

Any ideas what the problem was and what caused it? And what did they do to solve it?
I believe it was a Christie projector.. I don't know about the processor.

Thanks in advance.
 

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Posted by Carsten Kurz (Member # 5396) on 10-21-2013, 09:09 PM:
 
They probably forgot to switch on the amps...

- Carsten
 

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Posted by Carlos Villalpando (Member # 7411) on 10-22-2013, 05:45 PM:
 
It was the first show of the day, so I guess it could be that. Thanks
 

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Posted by Joe Redifer (Member # 3) on 10-22-2013, 07:04 PM:
 
Sounds like they were switching off the amps at night via the switches on the amps themselves. What's the point of that? When you arrive, you turn ALL the breakers on at the circuit box and go about your day. Or you have Film-Tech's automation power them up for you automatically.
 

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Posted by Mike Blakesley (Member # 26) on 10-22-2013, 10:34 PM:
 
I think the power switches must be the cheapest thing in any piece of equipment, when they SHOULD be the most heavy duty. I've had power switches fail in everything from our digital projector to lighting controllers when I was a DJ.
 

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Posted by Marcel Birgelen (Member # 6801) on 10-23-2013, 04:02 AM:
 

quote: Joe Redifer

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What's the point of that? When you arrive, you turn ALL the breakers on at the circuit box and go about your day.

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quote: Mike Blakesley

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I think the power switches must be the cheapest thing in any piece of equipment, when they SHOULD be the most heavy duty. I've had power switches fail in everything from our digital projector to lighting controllers when I was a DJ.

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