Film-Tech Forum ARCHIVE: Dolby Cp65 PinkNoice

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Posted by V.V.Tushit Vijay (Member # 5455) on 05-16-2010, 01:31 PM:

Can i eq an Dolby cp65 cinema processor with out pink noise card. did i had any source for it can any one help me in this topic.

Posted by Marco Giustini (Member # 4544) on 05-16-2010, 04:28 PM:

Hello

You can use a pink noise generator (i.e. from a PC) and connect it to the 6 channel input of the CP65 one channel at the time.

The only issue is the level, you should need calibrated pink noise to have the correct level in the auditorium.

To set up analog subwoofer you cannot use digital input though. What I did when I didn't have a Cat 85, I played some pink noise through one channel of Non Sync inputs after the EQ and after all channel were levelled (make sure you disable all pro logic and other stuffs!) and set the sub level to 0dB on RTA.

Personal suggestion: don't touch anything if you are not confident about what you're doing.

Marco

Posted by Demetris Thoupis (Member # 833) on 05-16-2010, 05:10 PM:

300 Mv on the above procedure is the correct inpuylt level for the 6 channel input so you get pretty much a calibrated pink noise. Not bad thinking. There is defibately a cheat for the cp200 to trigger pisnk noise without a generate cardbut I am not sure if such a cheat exists for the cp65.
Demetris

Posted by Pete Naples (Member # 761) on 05-16-2010, 05:16 PM:

Has anyone ever looked at the pink noise most of these PC programs generate, I mean look at it with a real RTA, not something running on the same PC?

I have and immediately changed my mind about it being of any use, I found it wasn't a; full range, b; flat.

Posted by Marco Giustini (Member # 4544) on 05-17-2010, 04:21 PM:

Yes I did and it was ruler flat. You definitely need a good sound card and a good software. You can't rely on a notebook sound card for tuning a sound system!

My D2 for example is a good source of Pink Noise but the Motu Traveller is a excellent quality sound card.

Posted by Pete Naples (Member # 761) on 05-18-2010, 05:54 AM:

Therein lies the problem, most soundcards are not that great.

I looked at it from 2 laptops and the desktop machine in my workshop, awful!

So to use the laptop as an RTA/pink noise generator, you'd need a good quality (read expensive) soundcard, and decent software.

Posted by V.V.Tushit Vijay (Member # 5455) on 05-18-2010, 02:52 PM:

As per Mr Marco said. i used an pink noise generator from my PC through TRUE RTA software. but i meant that it was not correct way to eq the system through them. a leakage sound in surround and sub woofer channels.

Note: if any one know how to get a old or new generator . just suggest me .ill try to get it from . and i required with cat 67 extender

Posted by Marco Giustini (Member # 4544) on 05-19-2010, 03:18 PM:

Wrong sound coming from the surround channel is more likely due to wrong A-Chain rather than B-Chain. I would check A-Chain first (you need an oscilloscope, an RTA and the proper test films) and B-Chain then. But you really need to know what you're doing here!

And, please, call me just Marco! [Smile]

Posted by V.V.Tushit Vijay (Member # 5455) on 05-22-2010, 07:20 AM:

Marco i made a chain perfectly. And i cannot able to get such frequency in B chain. Can i get the complete details. how to connect with PC and which software to be used. I used TRUE RTA and EVA SMMART LIVE. both i runned Pink noise generator..