Film-Tech Forum ARCHIVE: surround sound issue with D-cinema

This is topic surround sound issue with D-cinema in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Robert LaValley (Member # 4319) on 10-06-2008, 10:41 PM:

I'm getting a crackling noise coming from random surround chanels during a DLP presentation of Appaloosa. It sounds like rice crispies basically. not very loud pops and crackles, but its there just the same. Any ideas? Dolby show player, show store, and cp650 is the equipment. It's not like I can run film-gaurd and make it all ok again.

Posted by Scott Norwood (Member # 30) on 10-06-2008, 10:59 PM:

Blown speaker(s)?

Posted by Mark Gulbrandsen (Member # 72) on 10-06-2008, 11:07 PM:

It sounds like you have a bad surround amp or you may be clipping the surround amp channels. Reduce the fader a bit and see if the breakups persist. If they do at the reduced fader setting then I'd suspect amplifier problems.

Hope this helps....
Mark

Posted by Tristan Lane (Member # 1169) on 10-07-2008, 11:57 AM:

Post Deleted

Posted by Jim Cassedy (Member # 4115) on 10-07-2008, 06:25 PM:

Slightly off topic but my main 'complaint' about Appolosa is that customers complain about the volume being low/difficult to hear.

We're using DTS audio, and I've found I have to run that film almost 2 or 3 points higher than normal to keep the customers happy.

The DTS XD-10 is feeding a CP-65. I don't know by how many db's each number on the CP-65 dial increreases the level, but if I ran any other print at that level in the past the sound would be blasting and EVERYONE would be asking to have it turned down.

I think this has something to do with the sound track mix, and is not the fault of the equipment.

The CP-65 was refurbished by Dolby and re-calibrated less than 6 months ago and all the speakers and the main amps were replaced as part of an overall upgrade in that auditorium less than a year ago. A quick sound level check by me with test signals and a test meter confirm that everything seems to be working within specs.

I'll have to see/hear what happens when I put another feature in that auditorium next week.

(Or I could try moving Appolosa to another auditorium and see if the low volume complaints follow the print)

Posted by Robert LaValley (Member # 4319) on 10-08-2008, 03:54 PM:

Well I swapped digital prints and put Nick and Nora in my "problem" theatre and apaloosa in another theatre. Turns out when I did this, the sound problem went away in the problem aud and did NOT follow the movie to the other aud.

gotta love computers. [Roll Eyes]

Update to this:

I found out from dolby that there is a software upgrade that should help with this and their engineers are working on a software upgrade for the cp-650 since this problem has surfaced in a few other places that run DO-RE-Mi players instead of the dolby showplayers like I have.

[ 11-17-2008, 01:22 PM: Message edited by: Robert LaValley ]