This is topic Non Sync on CP500 in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Travis Cape (Member # 466) on 07-26-2000, 05:59 AM:
We just upgraded from mono to Dolby Digital last week. I am having a great time so far, except for the house music. We still have a curtain so I have always had trouble with the horns getting through the curtain. I played a mono CD and tried to balance the left and right channels but this seems to result in a terribly muddy sound when the curtain is closed. So far, I have adjusted the right channel down to nearly nothing and it sounds OK. It sounds kind of like the mono before. Does anyone have any suggestions with this?
Posted by Antonio Marcheselli (Member # 373) on 07-26-2000, 06:29 AM:
Hello.It was a big improvement... From Mono to Dolby Digital 
The first CP500 I saw had the sk7 set to "Non-Sync" format. In that way Subwoofer and surrouns are disabled and the sound come in Stereo from left and right channels.
If you build a custom format, you can reach a better result.
I didn't understand very well how it works exactly but if you set "Pro Logic" I don't remember where (I don't have a Cp500 here!)you will hear almost all sound coming from center channel and surrounds will start playing. I think that with a Dolby encoded CD also right and left channels can play something...
Otherwise if you set "Lt/Rt" (or similar) you will hear left and right channel playing stereo music whit active surrounds.
Then you can enable the subwoofer output cut from 50 to 180 (If I remember correctly) Hertz and with or without +10dB gain.
For better "Dolby" performance I think you should set the left and right input on cat 681 so that a CD can boost the graphic equalizer up to 0Db. In that case probably you have to turn down the master volume.
I can't use this settings since when you press "Mute" to fade out the house music if the fader is not 5 or higher the fade out is not very good...
Hope to put not too much syntax errors...
Bye
Antonio
Posted by Ari Nordström (Member # 288) on 07-26-2000, 11:14 AM:
I had the same problem when we installed a CP500. I disliked the Pro-Logic alternative for many reasons. For one thing, not all CDs can be played with acceptable results in matrixed mode, especially when the screen channels are hidden behind a curtain and the resulting sound is muffled. Also, it was important to define a _screen_ format for non-sync with no surround channels, since we sometimes need to plug in external sound sources (DAT, mixer board, etc) for special occasions.The solution was to plug in an external equalizer between the CD player and the CP500 and compensate for the curtain. This solution works extremely well. I made a custom format with L, R, and the subwoofers and made up a nice non-sync curve using my ears (and a couple of CDs well known to me). If you want a more professional approach and have the gear for it (RTA and mic), there are CDs available with pink noise.
The equalizer was a used 2x10 band Yamaha that I got for almost no money at all. You don't really need anything fancier than that.
We've received many compliments from our patrons for the non-sync sound. In fact, the non-sync sound is often better than the actual movie sound since we primarily show old movies.
Posted by Aaron Sisemore (Member # 145) on 07-26-2000, 03:36 PM:
I agree, non-sync of any kind sounds like crap when it has to go thru a thick curtain.With a CP500 you should have the option to create a custom format that would let you route the non-sync L&R channels to the LS and RS channels, giving you clearer nonsync without the mud that the curtain provides...
Aaron
Posted by Travis Cape (Member # 466) on 07-26-2000, 04:31 PM:
I think I'll try both of the approaches. We had a EV equalizer in our old sound system. It should be easy enough to patch it into the CD player and the CP500. I did build my own format on Non Sync 2, in case I messed it up! It sounds much better, but could use some more help.
Posted by Ari Nordström (Member # 288) on 07-26-2000, 04:47 PM:
What I found when creating a through-the-curtain non-sync curve was that I needed to raise 2k, 4k, 8k and 16k quite a bit. The 4k area is pretty sensitive in our auditorium, though, so I had to be really careful there. How much you need to compensate for the curtain depends on its thickness, of course.