Film-Tech Forum ARCHIVE: turning on the center channel in non-sync

This is topic turning on the center channel in non-sync in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Josh Jones (Member # 447) on 03-10-2002, 01:08 PM:

is there any way to do this? the center indicator is lit when non sync is running, but it is not making it to the speakers. can you modify the control card to do this?

Josh

Posted by Gordon McLeod (Member # 33) on 03-10-2002, 01:17 PM:

It would be helpfull to know the processor in question

Posted by Steve Kraus (Member # 476) on 03-10-2002, 03:29 PM:

What is it you want to hear on C? Note that music mixed for 2 channel stereo playback tends to bunch up in the center when subjected to matrix playback* it was not mixed for which is why normally (on a Dolby CP) non-sync just sends L & R straight through and uses the matrix only to create some ambience in the surrounds via the out of phase components.

On my CP500D I use a custom format for NS so that I can patch L over onto C because otherwise it would be very low on the C-weighted hearing impaired output. The "virtual patch bay" as I call it makes this trivially easy to do. The custom format also makes use of the sub which I don't think the normal NS does but I could be recalling that wrong.

* For this reason Dolby has always recommended filmmakers using existing music try to get a multitrack version to work from so it can be mixed for decent matrix playback rather than just using a 2-channel mix. Probably all the more so with a 5.1 mix.

Posted by Paul G. Thompson (Member # 655) on 03-10-2002, 03:30 PM:

Josh, which processor are you referring to? The CP-55 or the Eprad StarScope?

With the Eprad StarScope, It looks like the non-sync will feed all channels, if I read the manual correctly.

With the CP-55, it looks like you are stuck with Left and Right channel input only on the non-sync terminals of TB-1.

In any event, just settle for L & R. It is the easiest way out. I really don't think you want to fiddle with the control card. Those get expensive if you blow it up.

Posted by Josh Jones (Member # 447) on 03-10-2002, 06:58 PM:

the processor in question is a CP 55. I just wanted to know if it could be done.

------------------
"Film is made of silver, video is made of rust"
'nuf said

Posted by Gordon McLeod (Member # 33) on 03-10-2002, 07:16 PM:

You will have to stuff diodes into the format card to make it do 4:2:4 matrix mode

Posted by Paul G. Thompson (Member # 655) on 03-10-2002, 09:41 PM:

Josh, lift one side of the diode in the INC line at the F-6 address on the 243 card. That should do it. I just got that info from Steve Guttag.

The Center N/S will be matrixed. If you do not like the "bunching" Steve Kraus was addressing, just simply re-attach the diode.

Gordon's method will allow you to make a new format if you elect to do so. As I understand it, this could be helpful to you for future expansion in your sound system such as using DVD or video sound formats.

Thanks, Steve. Your information is much appreciated.