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» Film-Tech Forum   » Operations   » Film Handlers' Forum   » Format 11 Vs Format 22 on CP650

   
Author Topic: Format 11 Vs Format 22 on CP650
Don Furr
Master Film Handler

Posts: 492
From: Sun City, Ca USA
Registered: Nov 2002


 - posted 07-31-2017 09:14 PM      Profile for Don Furr   Email Don Furr   Send New Private Message       Edit/Delete Post 
Using Format 11 (6 channel input) I'm able to play the four channels from my 35mmm mag reader. I set up U1 for Format 22 which displays "4 Channel Mag Stereo) The problem is the surround track will not play.
What am I missing?

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12156
From: Annapolis, MD
Registered: Dec 1999


 - posted 08-01-2017 07:10 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
A 12KHz pilot tone to turn the surround channel on? Is the print you are playing absent from having the pilot tone?

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Don Furr
Master Film Handler

Posts: 492
From: Sun City, Ca USA
Registered: Nov 2002


 - posted 08-01-2017 07:51 AM      Profile for Don Furr   Email Don Furr   Send New Private Message       Edit/Delete Post 
Steve I'm using a Smart 435 preamp which doesn't have the 12hz tone capability like the older 430 preamp. Using Format 11 the surround channel is constantly present.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12156
From: Annapolis, MD
Registered: Dec 1999


 - posted 08-01-2017 09:45 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
The tone is on the film. If the preamp is passing the tone to the CP650, then it would be up to the CP650 to turn the surrounds on/off based on that tone.

That said, I have never configured the CP650 for format 22 so I don't know if that is the issue or not but when I hear no surrounds, then I think the pilot tone is not being triggered to turn them on.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16160
From: Bountiful, Utah
Registered: Jun 99


 - posted 08-01-2017 01:57 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
You ought to get your self a real Dolbly MPU and get rid of the Smart thingy. The Smarts never had any bottom end response to them. If you hunt around you might even find a 12khz switching card for the Dolbly MPU.

Mark

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Sam D. Chavez
Film God

Posts: 2083
From: Martinez, CA USA
Registered: Aug 2003


 - posted 08-01-2017 04:43 PM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
The 12Khz card is rather rare for the MPU. Mostly they were sold for 70mm and even though there is a card bay for 35mm Cat. No. 92's is was usually not purchased with that card. Often they there were fitted with a 12 Khz bypass card.

I look forward to hearing the answer to why the surround channel is not getting through as well.

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Don Furr
Master Film Handler

Posts: 492
From: Sun City, Ca USA
Registered: Nov 2002


 - posted 08-04-2017 04:49 PM      Profile for Don Furr   Email Don Furr   Send New Private Message       Edit/Delete Post 
Back on this project after 3 days out of town.

Steve....I was not aware that the CP650 had the ability to detect the 12Khz tone and turn it on/off.

Mark....I had the complete Dolby MPU with the card and sold it a couple of years ago.

Sam....I hope to get to the bottom of this issue soon.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12156
From: Annapolis, MD
Registered: Dec 1999


 - posted 08-04-2017 04:54 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
Don, I don't know for sure that the CP650 does decode the 12KHz tone, it was just a gut reaction to the symptoms you described. I'd have to research it to get a definitive answer.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16160
From: Bountiful, Utah
Registered: Jun 99


 - posted 08-04-2017 05:33 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
You should buy that Dolby MPU back!The Smart is a POJ....

Mark

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Don Furr
Master Film Handler

Posts: 492
From: Sun City, Ca USA
Registered: Nov 2002


 - posted 08-04-2017 11:37 PM      Profile for Don Furr   Email Don Furr   Send New Private Message       Edit/Delete Post 
So here's a quote from the operator's manual for the CP650:
Format 22

35mm Composite Magnetic 4-Track
Standard 4-track, no NR, magnetic filter

Is it possible that the term "magnetic filter" suggest there is a 12Khz filter build in the processor?

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12156
From: Annapolis, MD
Registered: Dec 1999


 - posted 08-05-2017 04:45 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
No. The magnetic filter means that it applies a reduced form of the Academy filter to knock down some of the highs/lows to "Conventional" magnetic prints without Dolby NR.

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