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Author Topic: help? CP45 + X-men = blech Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 05-20-2009 05:26 PM                     Hi again. Smallish house with a CP45 and CE analog reader, passive crossover speakers (JBL) and USA900 amps. Sound is fuzzy especially on right channel. It is audible on my trailer test reel but I would say not objectionable, but there isn't much except loud sound on the trailers. On X-men Origins the sound is really bad, lots of distortion in the right channel particularly. Most serious with speaking level, explosions etc just sound loud as usual. SO far I've changed a bad amplifier (fan gummed up, thermal cutout every few minutes - but sounds OK), the CP45, and the CE reader unit. The distortion stays with the amplifier channel, ie the speaker itself is OK. Sound is fine in mono ("enhanced mono" using LCR). Sounds better in "A" than SR. I know the CP45 SR is unexcellent, but this is beyond the usual 222 SR/A fuzziness. The only thing I have not changed so far is the CE red LED or power supply. Dolby tone, buzz/LR, and pink noise look and sound OK. NS sounds OK. I changed out the processor thinking the matrix must be going screwy. Today was rather frustrating when the dang thing still sounded bad. The cinema swapped X-men to another house and they say it sounded fine (another CP45) but I wonder about the print anyway. Any ideas before my next visit? I'm kinda low on them now.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 05-20-2009 08:26 PM                     I have had the readers particularly the solar cell go bad usually it starts with a lot of distortion and then fails try running jiffy on it Also run the cat 97 l/r film and look at thel and r outputs in SR with a scope  |  IP: Logged Scott Christopher Film Handler Posts: 69 From: Adelaide, South Australia Registered: Apr 2001 posted 05-21-2009 12:02 AM                     Years ago I had problems with the booster pre-amp being faulty on one of our readers. From memory, It was the either the TL-072 or TL-074 op-amp on board.  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 05-21-2009 06:28 AM                     Agreed the reader seems to be a likely suspect. I've tried two others: a shop spare and one from another system at the same cinema that sounded fine. Is there any way the actual LED array could cause noise and "fuzzy" distortion in the audio?  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 05-21-2009 08:32 AM                     If some of the actual LED segments have failed it will be very distorted  |  IP: Logged Kenneth Wuepper Phenomenal Film Handler Posts: 1026 From: Saginaw, MI, USA Registered: Feb 2002 posted 05-21-2009 08:43 AM                     Dave, I don't understand your last post. Did the two other readers clear up the problem or is the sound still bad in the right channel? In answer to your question, missing or dark segments of the LED array can cause distorted sound. It looks to the reader like there is no information in that area of the sound track. At certain levels where the volume places peaks of information in the dark area, it will sound like the track is clipping, as they are not scanned. Lesser or greater volumes will have some distortion but will not exhibit the clipping as described above. KEN  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 05-21-2009 04:27 PM                     Neither swapped reader fixed it - the shop one wasn't definitely good, the one from another cinema was at least sounding OK there. I will take a new LED and inspect the array to see if there are dark spots. I can see if a segment is dark near a channel track centre line then low level sound would be distorted. I did, however, realign the LED for best output level and recentred it on the sound track by eye with a mirror. The sound problem didn't change then.  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 05-21-2009 06:54 PM                     Perhaps a use for that otherwise-unused Cat. 566 uniform illumination test film. --jhawk  |  IP: Logged Pete Naples Phenomenal Film Handler Posts: 1565 From: Dunfermline, Scotland Registered: Feb 2001 posted 05-22-2009 11:43 AM                     quote: John Hawkinson unused Cat. 566 Whit?! It's one of my most used!  |  IP: Logged

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