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Author Topic: Needing help w/ popping noise coming from speakers David L Parlier Film Handler Posts: 23 From: Franklin, NC, U.S.A. Registered: Oct 2003 posted 12-19-2003 02:14 PM                        A while back, we installed some newer sound equipment in one of our projection booths. A few months after the installation, I began to notice a popping noise (or small crackle) coming from the speakers in the auditorium. This popping noise is not constant and can randomly occur anywhere from 2 to 8 times in a fifteen minute period. It also only seems to happen only when the movie is playing, and not when playing music before the show. So far I have tried to following: 1) Make sure that everything was as clean as humanly possible. 2) Checked and made sure all connections were tight. 3) Check to make sure that everything was grounded properly. We ended up having a electrician run a new ground wire from the main electrically panel box. 4) Switching out the board on the sound processor. 5) Put in an automatic voltage regular / line conditioner that the sound processor plugs into. None of this has helped with the popping noise in that auditorium. I am sure that many of our patrons do not hear this popping but some do, and it bugs the hell out of me. Does any else have any solutions or suggestions? Here is what we have in that booth - Smart MOD IIC Digital/Optical Stereo Processor - Smart MN600 6-Channel Monitor - Kelmar Advance Technology LED - QSC Amps (can provide model numbers if numbers) - All JBL Speakers (can provide model numbers if numbers) Any help would be greatly appreciated. Dave  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 12-19-2003 02:23 PM                        Sometimes a random "popping" noise can be due to static discharge, likely near low level audio signal lines. Be sure to follow all the guidelines to minimize static issues: proper relative humidity, proper grounding, treat non-conductive film handling components (e.g., painted platter surfaces, plastic rollers) with a conductive antistat, etc. Random "popping" can certainly also be due to a faulty component or connection. (P.S., please use a more descriptive topic than "Needing some suggestions")  |  IP: Logged Darryl Spicer Film God Posts: 3250 From: Lexington, KY, USA Registered: Dec 2000 posted 12-19-2003 06:12 PM                    does this popping happen in all channels or just the center channel or ather channel. Did you check your sound head for loose connections.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 12-19-2003 06:17 PM                     On the smart mod2c switch it to mono and also try it in bypass to see if it is present The reason is that in mono an as that removes the matrix and noise reduction from the equation The EQ and output stage should be ok since it doesn't do it in music and they are common as is the amps and speakers and monitor In Bypass mode a seperate optical preamp is used so if it presists then it is in the reader check the connections to the reader and the powersupply if that proves to be the source Also on smart's website is some detailed information re grounding issues with reverse scan readers and their processors  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 12-19-2003 06:38 PM                     I had this problem a while back and -- in that case -- it turned out to be a problem with a loose connection on the Kelmar LED power supply. I got a replacement but the old one worked fine after the molex plug was resoldered to the board. I can't tell if I am explaining this very well. I'll see if I took photos that time. Of course, this info may or may not help in your case. Good luck! Be sure to let us know how it all turns out.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 12-19-2003 06:43 PM                     If it is one of the white kelamr supplys with the single trim pot on the board I have had the molex burn and corrode as well in a couple of locations  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 12-19-2003 07:22 PM                     Manny, I've had the same problem with Kelmar supplies as well. Its best to completely get rid of the Molex's and solder the wires directly to the pcb. For what ever reason Molex's seem to be the plague inside cinema power supplies. Mark @ CLACO  |  IP: Logged Bruce McGee Phenomenal Film Handler Posts: 1776 From: Asheville, NC USA... Nowhere in Particular. Registered: Aug 1999 posted 12-19-2003 08:04 PM                     Back in the 1970's, alot of color televisions used Molex connectors. I never saw them give problems. Whats the deal with what they are using now? Just cheap?  |  IP: Logged John Anastasio Master Film Handler Posts: 325 From: Trenton, NJ, USA Registered: Sep 2000 posted 12-19-2003 08:25 PM                        Molex's were a problem for me on some radio station tape equipment. They'd corrode and turn into strange resistances. I never liked 'em. You're right, Bruce. I remember them being used in those big old TV's between stages.  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 12-19-2003 09:12 PM                     Sounds like a static discharge to me. Is there a possibility of amplifier input and output cables running parallel in the same bundle? I have run into that a couple of times, and separating the cables and sending them on a different route cleared the problem.  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 12-19-2003 09:58 PM                  I agree, sounds like a static discharge problem to me as well. Make sure you have the correct booth humidity and proper cabling and grounding. Molex connectors are very reliable and a great connector IF used properly and have the ***correct contact material***. Unfortunately, there were too many wanna-be engineers that had no clue as what material to specify for contacts. That lead to the failure of many connectors. >>> Phil  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 12-19-2003 11:31 PM                     If it was amp cables causing it would be there in nonsync as well The trouble with molex connectors is they often are not properly made with the right crimp  |  IP: Logged Marc Jones Film Handler Posts: 82 From: Elizabethtown, KY Registered: Jun 99 posted 12-20-2003 12:00 AM                     Just curious if the popping noise is consistant when the platter feedout platter switches on, I know have had that happen before just a thought good luck  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 12-20-2003 12:45 AM                  I agree Gordon, the proper crimping tool and method is very important in all crimp connections...molex or not! >>> Phil  |  IP: Logged Richard Hamilton Phenomenal Film Handler Posts: 1341 From: Evansville, Indiana Registered: Jan 2000 posted 01-02-2004 08:21 PM                     Just curious? Like Marc said, does the auditorium have a platter with micro-switches? I ran into this same problem at an older theater with Potts platters. Rick  |  IP: Logged

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