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Author Topic: Digital cinema sound problem
Thomas Pitt
Master Film Handler

Posts: 266
From: Leeds, West Yorkshire, UK
Registered: May 2007


 - posted 11-19-2007 05:58 PM      Profile for Thomas Pitt   Email Thomas Pitt   Send New Private Message       Edit/Delete Post 
I've just come back from seeing half of Beowulf in 3D. Yes, half of the movie - the other half was ruined by a malfunctioning sound system!

Everything started up properly; a 30-minute advert and trailer reel (35mm) which then changed over to the Real D system for the movie. During the first half of the movie, there were a couple of noticeable 'bloops' on the audio, but that was nothing compared to what happened later!

Approximately halfway through the movie, around the point where the golden horn returns to Beowulf, all the sound channels went to white noise at maximum volume! The white noise cut off after about 30 seconds and the movie sound returned, but only in the centre front channel. From that point onwards, the white noise kept blasting out at random - sometimes returning to the movie sound, other times to silence.

Many people in the auditorium, myself included, covered their ears when the white noise struck - some kept their ears covered afterwards in case it happened again!
During the silence I could just hear a beeping noise coming from the booth - perhaps some alarm?

Sometimes the noise was more like air blowing across the top of a microphone, but most times it was like when you play a data CD on an audio CD player.

After 10 minutes of sitting there with my fingers in my ears, I'd had enough - we called the manager, who gave us all a refund and a free ticket to any other showing in the cinema. I could still hear the white noise blasting out of the auditorium occasionally, even when standing in the lobby - that gives you some idea how loud it was!

Anyway, the reason I'm posting this here is to ask if any of you have had similar problems with digital cinema audio. Based on the symptoms I describe, what would you say happened to the sound system?

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16555
From: Bountiful, Utah
Registered: Jun 99


 - posted 11-19-2007 07:18 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Well, that certainly is the pitts when something like that happens!

I've had the same thing happen with the USL VX crossovers. They have on occasion put out full level noise of some sort into the B chain blowing all the HF diaphrams in the process.

I'd be curious to know what Digital Server they were using for that show. Servers will still do occasional wierd things but generally nothing that a system re-boot won't solve. Donno about other servers but the Dolby Server after re-booting will just start up where it left off.....

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Dustin Mitchell
Phenomenal Film Handler

Posts: 1865
From: Mondovi, WI, USA
Registered: Mar 2000


 - posted 11-20-2007 05:07 AM      Profile for Dustin Mitchell   Email Dustin Mitchell   Send New Private Message       Edit/Delete Post 
The doremi, at least with AccesIT's software, has a 'recovery point' for restarting a show after reboot as well.

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Mark J. Marshall
Film God

Posts: 3188
From: New Castle, DE, USA
Registered: Aug 2002


 - posted 11-20-2007 07:17 AM      Profile for Mark J. Marshall     Send New Private Message       Edit/Delete Post 
That does suck! For what it's worth, I've seen an SDDS DFP-D2000 do that. Not digital cinema, I know, but the sound is digital so I thought I'd throw it out there.

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David Graham Rose
Expert Film Handler

Posts: 187
From: Cambridge, UK
Registered: Sep 2002


 - posted 11-20-2007 01:33 PM      Profile for David Graham Rose   Email David Graham Rose   Send New Private Message       Edit/Delete Post 
Greetings

Another example of the half-baked cauldron of bodgery that is D-Cinema at the moment!

David

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Dustin Mitchell
Phenomenal Film Handler

Posts: 1865
From: Mondovi, WI, USA
Registered: Mar 2000


 - posted 11-20-2007 03:09 PM      Profile for Dustin Mitchell   Email Dustin Mitchell   Send New Private Message       Edit/Delete Post 
Because 35mm sound systems NEVER have any problems [Roll Eyes] .

Digital projection still uses a cinema sound processor btw so it is perfectly possible that is what was at fault in this case.

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Bobby Henderson
"Ask me about Trajan."

Posts: 10866
From: Lawton, OK, USA
Registered: Apr 2001


 - posted 11-20-2007 04:11 PM      Profile for Bobby Henderson   Email Bobby Henderson   Send New Private Message       Edit/Delete Post 
The first time I saw Interview with the Vampire, at the AMC Memorial Square 8 in Oklahoma City (a theater which no longer exists), its Dolby Digital system crapped out big time in the middle of the movie -with very loud white noise being the result. The staff had to stop the show for around 10 minutes. When the show resumed it played only in analog.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16555
From: Bountiful, Utah
Registered: Jun 99


 - posted 11-20-2007 04:25 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
quote:
Another example of the half-baked cauldron of bodgery which is called Film at the moment!

David, I think I'll have that put on a t-shirt and wear it during my upcomming D-Cinema installs [Cool]

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Peter David Bruce
Expert Film Handler

Posts: 187
From: East Anglia -England
Registered: Aug 2007


 - posted 11-21-2007 09:16 AM      Profile for Peter David Bruce     Send New Private Message       Edit/Delete Post 
ok im having this problem (to a lesser degree) alot of beeping on the soundtrack itself (most noticably in the quiet bits). ive cleaned and cleaned it and simply cannot remove the problem.

im running CP650 Dolby Processors, with Ashly FTX Series III amps. Dolby EX.

i need to sort this if i can. id hate to think im stuck with it, or it may get worse...

also the print is constantly running at error rate 7!

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Patrick de Groot
Expert Film Handler

Posts: 161
From: Sprang-Capelle, Netherlands
Registered: Apr 2001


 - posted 11-21-2007 10:17 AM      Profile for Patrick de Groot   Email Patrick de Groot   Send New Private Message       Edit/Delete Post 
I suppose you're using a 35mm print.
Option 1: bad/damaged film print (if other prints play ok)
Option 2: bad alignment of sound head
option 3: one or more defect LEDs (look at the leds through a cd)

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Peter David Bruce
Expert Film Handler

Posts: 187
From: East Anglia -England
Registered: Aug 2007


 - posted 11-21-2007 10:30 AM      Profile for Peter David Bruce     Send New Private Message       Edit/Delete Post 
thanks patrick. i will investigate

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David Graham Rose
Expert Film Handler

Posts: 187
From: Cambridge, UK
Registered: Sep 2002


 - posted 11-21-2007 01:54 PM      Profile for David Graham Rose   Email David Graham Rose   Send New Private Message       Edit/Delete Post 
Greetings Mark!

"David, I think I'll have that put on a t-shirt and wear it during my upcomming D-Cinema installs"

When you do, please send me one. I have yet to see a system that works correctly, despite being a convert to D-Cinema!

Goodnight

David

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Louis Bornwasser
Film God

Posts: 4439
From: prospect ky usa
Registered: Mar 2005


 - posted 11-21-2007 03:35 PM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Me, too!! Sounds like a profitable venture for someone. Louis

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