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Topic: Dropping out of Digital Alarm

Markus Lemm
Expert Film Handler

Posts: 113
From: Ottawa, Ontario, Canada
Registered: Nov 2005

posted 10-26-2007 01:13 PM

Just wondering if there is a way to setup an alarm that sounds when the processor drops out of digital.
At my cinema we have a CP55 that goes into AUX when processing digital and goes to SR when the digital cuts out. Is there a way to add a circuit that rings a bell when the processor switches out of AUX?

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Pete Naples
Phenomenal Film Handler

Posts: 1565
From: Dunfermline, Scotland
Registered: Feb 2001

posted 10-26-2007 04:03 PM

Whilst it wouldn't be difficult to do something like this by using the status outputs of the CP55, I have to ask, why?! If it's reverting when the SR.D track is not playable for whatever reason, it's doing it's job!

Or have you been watching 'Das Boot'?

ALARM!!!!!!!!!!

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Jack Ondracek
Film God

Posts: 2348
From: Port Orchard, WA, USA
Registered: Oct 2002

posted 10-26-2007 06:30 PM

I could think of one practical reason for this.

We've had prints that were so hacked up, the SRD was useless. However, that didn't keep the Dolby from trying. At 6-F error rate the sound can be pretty ragged. If it hunts back & forth from SR to SRD whenever it gets a decent section of film, it can sound downright awful. In cases like that, we've bypassed the SRD, but not before the problem lasting much longer than we would have liked.

Some kind of audible that would indicate a problem would be handy in a case like this.

quote:
ALARM!!!!!!!!!!

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Pete Naples
Phenomenal Film Handler

Posts: 1565
From: Dunfermline, Scotland
Registered: Feb 2001

posted 10-26-2007 06:35 PM

In which case, switch the SR.D off whilst the distributor organises a decent print. Surely prints are rehearsed before public exhibition?

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Ken McFall
Jedi Master Film Handler

Posts: 615
From: Haringey, London.
Registered: Apr 2001

posted 10-27-2007 04:46 AM

"surely prints are rehearsed before public exhibition..."

and now back to the real world.

Prints often arrive on the morning of the opening date or there is no time allowed for print rehersal in the budget.

Therefore an audible indication would be most helpful especially during the first run to let the operator know if there is a fault with the print's SRD track.

You need to know you have a problem before you decide to bypass SRD.

Being Proactive rather than Reacitive may best describe such a need. Sort it out before the audience complain.

and now we returm you back to the fantasy world where everything is rehersed and nothing ever goes wrong.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 10-27-2007 08:20 AM

Simple...turn off the analog LED....when the audience comes out demanding their money back for lack of sound...you will get your audible alarm!

But on the CP55, where they have status ID lines designed to light LEDs on a remote (ID0 - ID7), you could use those lines to trigger an alarm. Note, they are current limited via a resistor to just have enough current to light an LED (20-30mA) so you will most likely need to use a transistor to fire something to make the visual or audible alarm.

Steve

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Markus Lemm
Expert Film Handler

Posts: 113
From: Ottawa, Ontario, Canada
Registered: Nov 2005

posted 10-27-2007 09:21 AM

Thanks for the input. I'll see if I can make use of the pulse that causes the jump to AUX. As for previewing a print before we show it is not an option since we usually only show a film a couple times than change the films. We are a second run theatre that does double bills and alot of films come by bus the day of the show.

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Jack Ondracek
Film God

Posts: 2348
From: Port Orchard, WA, USA
Registered: Oct 2002

posted 10-27-2007 09:24 AM

quote: Pete Naples
In which case, switch the SR.D off whilst the distributor organises a decent print. Surely prints are rehearsed before public exhibition?

It's an extreme case for us, but it has happened. If I get a crappy print on Friday afternoon, I'm shot until at least Saturday. Being a drive-in operator, "rehearsing" shows is a luxury I don't have. Puts a bit more pressure on during inspections!

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 10-27-2007 10:14 AM

I totally understood the point of this thread until this post...

quote: Markus Lemm
Thanks for the input. I'll see if I can make use of the pulse that causes the jump to AUX. As for previewing a print before we show it is not an option since we usually only show a film a couple times than change the films. We are a second run theatre that does double bills and alot of films come by bus the day of the show.

So let's see what we have here.

*Your CP55 automatically switches to SR in the event the digital fails.

*Your prints usually arrive the day of the show so there is no time to pre-check the print and order another.

*You generally only run prints for maybe 2 days before you ship them.

So in your situation what difference does it make? By the time that alarm goes off, you can't get another print anyway and it will just default to SR. (The 6-F problem is the only legitimate reason I can see for this, but note that usually is NOT enough to kick the processor out of digital, hence your alarm wouldn't go off anyway.)

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Markus Lemm
Expert Film Handler

Posts: 113
From: Ottawa, Ontario, Canada
Registered: Nov 2005

posted 10-27-2007 10:30 AM

Well Brad,
I'm interested in giving the best possible presentation every time, which is very difficult based on the amount of print traffic and sometimes total garbage condition of prints that I handle on a daily basis.
The alarm is there so I can do something about the problem right away instead of having the film jump from analog to digital and back throughout the print, which sounds like crap.

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Chris Slycord
Film God

Posts: 2986
From: 퍼항시, 경상푹도, South Korea
Registered: Mar 2007

posted 10-27-2007 10:49 AM

Could you rig up an alarm that goes off if the error rate goes above a certain point?

That said, it's not that uncommon for a print to go to "F" for just one moment and not have it happen again during a show.

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005

posted 10-27-2007 11:30 AM

What you need is an alarm that does not go off if an occasional "SR" happens, but say 5 revisions in 3 minutes would trigger it so that you can then disable the DIGITAL led. Older revisions would then "time out" after 3 minutes.

While an occasional "bad print" can be a problem, this kind of digital trouble, even on second run, even in "the sticks" would point me to a less-than-ideal Dolby Digital alignment issue. I have not seen "failure" to be a problem with a correctly set-up system, even on some very bad prints. Louis

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 10-27-2007 01:03 PM

Louis, it is prevalent all around actually. I can understand his reasoning, but fact of the matter is that there are many machines that if you do not use FilmGuard or some sort of film lubricant on them, the SRD tracks WILL get scraped right off rendering even a perfectly aligned Kinoton SRD reader that would typically track at 0-1s nothing but Fs. Century projectors however are not one of them, and I know that is probably 90% of your client base. [Wink]

After Markus' most recent post, I think his best solution is to upgrade his analog system. There shouldn't be THAT much of a difference when the two formats switch back and forth. Even if his system is perfectly aligned, the offset may be just a tad bit off giving that "skipping" effect. This is why I prefer to set SRD offset via a known loop of dialogue as compared to the SR track, rather than the sync pop test film.

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

posted 10-27-2007 01:23 PM

quote: Brad Miller
there are many machines that if you do not use FilmGuard or some sort of film lubricant on them, the SRD tracks WILL get scraped right off rendering even a perfectly aligned Kinoton SRD reader that would typically track at 0-1s nothing but Fs

What kind of crappy projectors are those? Simplexes don't do this, either. Nor do Kinotons or Cinemeccanicas.

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Josh Kirkhart
Expert Film Handler

Posts: 165
From: Austin/Houston, TX, USA
Registered: Nov 2001

posted 10-27-2007 02:38 PM

Go get an old DTS-6D and otherwise use SR.

If print holdover is that short and print condition so bad why attempt to keep SR.D. With a 6AD you have better chance of great sound on a crappy print than SR.D(if you can get the discs! Maybe a partnership with a first run for discs)

clean the prints!

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