Film-Tech Forum ARCHIVE: Installing CAT160 OBE in CP50

This is topic Installing CAT160 OBE in CP50 in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Tom Wienholt (Member # 1510) on 02-02-2003, 12:41 AM:

I wanted to know how to install a CAT160 subwoofer card in a CP50 with out the adaptor that is necessary to use the CAT85 as a pink noise source. I have another pink noise source but it can only put out a 150mv signal and according to instructions a 600mv pink noise signal is needed. Any help would be appreciated.

Posted by Steve Guttag (Member # 268) on 02-02-2003, 10:38 AM:

For tuning the sub (parametric EQ)...any Pink Noise source will do and is injected on one of the test points on the front of the card.

As to balancing it out...you could even use pink noise test film to get you in the ball park.

If you know of anyone that has Ultra Stereo's TT-1 test film, that would be the one to use since it is pink noise recorded at about 50% modulation so it should be at the cusp of not having any interaction with the NR expander.

Steve

Posted by Tom Wienholt (Member # 1510) on 02-02-2003, 11:28 AM:

Thanks for you help.

Posted by Bas Haldermans (Member # 1521) on 02-02-2003, 04:25 PM:

I've installed a cat 160 in a CP50, I was wondering indeed how to equalize the subwoofer. I only have the cat 85 pink noise generator.

Bas

Posted by Gordon McLeod (Member # 33) on 02-02-2003, 06:50 PM:

I think steve already covered that
Dolby makes a little adapter board that allows the 85c to plug into the preamp slot
Also connect a pink noise gen. to the Lt and Rt preamp out terminals (unplug the preamp) and raise the level to just above the dot on the NR card

Posted by Tom Wienholt (Member # 1510) on 02-02-2003, 11:04 PM:

For EQing the Subwoofer, wouldn't pink noise test film be pretty much the same as using a pink noise generator? Basically the amps for all other channels would be turned off in order to isolate the subwoofer. Correct?

Posted by Steve Guttag (Member # 268) on 02-02-2003, 11:12 PM:

Not exactly...you have to make sure the PN is above 50% modulation on the test film or you will have the effects of the NR's decoding circuitry mixing in.

Steve

Posted by Sam Hunter (Member # 1119) on 02-19-2003, 07:26 AM:

I have the dolby CAT69C test film. That pink noise level is not high enough to work properly? I dont have the CAT 85 card so could I use any pink noise source?
You mentioned removing the preamp card, could you use the preamp card to bring up a low level pink noise source as well? I was planing on using my PC,s sound card and generator program as a source. Any harm in doing this?
Thanks.