Film-Tech Forum ARCHIVE: The back channel at SR playback on CP500

This is topic The back channel at SR playback on CP500 in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Alex Batyaev (Member # 2701) on 09-30-2004, 04:37 PM:

Hi, All!

We have CP500+SA10 in one of the cinema halls. At playback of analogue tracks in SR mode, the back acoustics for some reason plays the sound that should be in the frontal central channel. The software in CP500 is of ver.1.61, so shows the processor. Does anyone know if it will show "ver.1.61EX" if "EX" is installed? And could it be the reason of such sound if the software is actually of ver.1.61? (I simply don't know if it was updated after installing the SA10).

Thnak you in advance.
Bye

Posted by Steve Guttag (Member # 268) on 09-30-2004, 04:45 PM:

Alex,

Your CP500 will only show 1.61EX if that version of the firmware was loaded into your CP500 when the SA-10 was installed.

In any event...you should not use version 1.61 as it is defective. It can dump your processor's memory and can also intermittently not accept automation cues.

Dolby has made available firmware version 1.65 and 1.65EX for the CP500. Your technician should obtain those and update your processor.

As to your problem. It sounds like the SA-10 was not installed properly or completely.

The SA-10, when not playing a digital soundtrack, should not have it's EX LED (red in color) lit. There is a ribbon cable that connects between the SA-10 and the CP500's "Automation" connector to allow the CP500 to turn the EX feature on and off.

If you play an optical film with EX on, all of the surrounds will be coming from the rear, as you describe.

If you mean that dialogue is also coming from the rear or surround channel then it sounds like the optical solar cell input was wired incorrectly such that one of the channels is out of phase and the pro-logic decoder in the CP500 is decoding the center channel to the surround rather than to the center.

Steve

Posted by Peter Hall (Member # 695) on 10-01-2004, 12:04 AM:

The SA10 would have to be REALLY badly installed to get the centre channel coming out of surround - the centre doesnt go anywhere near the SA10.. We've had the right hand 675 (slot J13 I think) screw up in the past, diverting channels where they shouldnt be. Easiest thing is to swap the two 675s over - sometimes hides the problem but more often than not the fault changes and at least you know you have a duff card

Posted by Patrick de Groot (Member # 858) on 10-01-2004, 07:46 AM:

When our CP65 + DA20 was first installed and playing Dolby SR (DD exciter lamp was broken), the center channel came from the surrounds, and the surrounds seemed to be coming from the center channel. I thought at that time that the amplifiers where wired wrong...
It appeared to be the wiring from the solarcell that was wrong (+ and - reversed). A stupid thing and it proved to me that the technician didn't test it properly...

Posted by Peter Hall (Member # 695) on 10-02-2004, 09:10 AM:

Yes, install sounds like it was wrong but hey, s__t happens, biggest question is who picked up the problem - you or the installer ? If your machine was a FP30 with a std cell then there is an inconsistency in the colours of the wiring and an easy mistake to make, esp if late at night or in a rush. Have done the same thing myself however immediately picked up on initial testing.

Posted by Patrick de Groot (Member # 858) on 10-02-2004, 10:44 AM:

quote: Peter Hall

biggest question is who picked up the problem - you or the installer ?

The installer was there that day, however he was gone when we were playing the movie that night. So we had to call them to say something was wrong...
As a positive note: The companies owner/technician came over to fixed it the same night.