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Author Topic: Raising One projector's analog surround levels Demetris Thoupis Phenomenal Film Handler Posts: 1240 From: Aradippou, Larnaca, Cyprus Registered: Apr 2001 posted 11-17-2002 04:27 AM                     I have this for you, In a changeover theater (v 5's with kelmar stereo solar cells) the first projector gives perfect distribution to all channels in analog and the surrounds rock the theater. On the second projector though, although the sound is clear, the surrounds are not lound enough. Forgot to mention that we are talking about a CP 65 processor. Is there something that can be done to raise the surround levels of the second projector only but not affect the surrounds of the first projector? Demetris  |  IP: Logged Pete Naples Phenomenal Film Handler Posts: 1565 From: Dunfermline, Scotland Registered: Feb 2001 posted 11-17-2002 05:26 AM                     In a word, no. BUT from what you've said I'd wager that the 'A' chains on both your machines need some attention. You really shouldn't be able to audibly detect any difference between them. You have checked Dolby level on both machines with the SAME loop of test film?  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 11-17-2002 11:11 AM                    It may simply need the levels set with Dolby Tone but if that does not correct the problem then you or your technician will need to get in there to see what is going on using a number of test loops, an audio analyzer (RTA) and oscilloscope. If you don't have these tools you won't be able to do it yourself. But please do check the levels first because it may be as simple as that. Make sure you clean the solar cell and the slit lens optics first. Perhaps consider putting in a new exciter bulb if the existing one is old and could be suffering from a sagging filament--if you do then do it before setting the level since it will change complete with the new bulb.  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 11-17-2002 03:49 PM                        If the Dolby level procedure does not cure the problem it is likely that the two solar cells are out of phase. In that case, the center channel should also be affected.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 11-17-2002 04:02 PM                     Could be the "working" projector's azimuth is just a slight bit off, resulting in a little more bleed to the surrounds. If this is the case and that is coupled with the surround outputs being just a bit too low, that could give the results you are hearing. Have you shut off all speakers except for the surrounds and listened for dialogue leakage?  |  IP: Logged Demetris Thoupis Phenomenal Film Handler Posts: 1240 From: Aradippou, Larnaca, Cyprus Registered: Apr 2001 posted 11-18-2002 06:24 AM                     Well, On the first projector we have almost zero (seriously) dialogue leakage, you have to stick your ear to the speaker in order to hear the dialogue in analogue sound. On the second projector we have a bit more leakage. So Brat. You are suggesting that is the azimuth?  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 11-18-2002 07:13 AM                     I have come across a couple of solar cells in my life where the two cells were partially shorted together such that you had a little of each signal in the other channel! This would cause the problem you describe. This shouldn't be confused with the normal crosstalk associated with forward-scan systems...this was an actual electrical short. Steve  |  IP: Logged Peter Hall Master Film Handler Posts: 314 From: London, UK Registered: Dec 2000 posted 11-18-2002 01:32 PM                        Sounds like the azimuth is out - if reference levels were off the dialogue would be over to one side. Is P2 less responsive at the top end ?  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 11-18-2002 01:58 PM                     Adjust your system so that the projector without dialogue leakage into the surrounds is balanced and sounds good. Then do a full A-chain on the other one and see if the problem does not disappear. If it doesn't, then it's time to start looking into other possibilities. Odds are it's just the azimuth on the A-chain.  |  IP: Logged

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