Sound System Interference...

[tmooney]

We have tracked the problem down and at least the main issue is not related to cell phones. I actually got to the electrical panel box and found out that the sound system is tied to the original section of the panel box. The electrical panel has been added on to on several occasions and the outlet that has the sound system is on the oldest section.

I am able to create noise in the system by turning off certain fluorescent ballasts in the back of the church. I tested all of the outlets and they are OK but something causes the random noise through the system. Next week I am going to shut off the breaker and see what is tied in. We do have an electrical guy who can replace the breaker if need be.

This is an old building and I do not have another outlet in the same area to plug the system into. The building is closing in six month so we have to make due with quick fixes.

Any suggestions.

[cmchamp]

What's the orientation of your electric box to the sound booth? How far, through what?

[tmooney]

We really don't have a sound booth per say. This is a small church and the whole sound system is self contained in one old and large rack mount unit that has everything mounted in it. Basically it is wired to a switch and it's either on or off. It was installed in the 70's and the cables run right into the wall, I can barely move the rack because their is no slack on the cables.

The electrical panel is on one side of the alter and the sound system is on other side. The alter has a room on each side for storage and dressing. I would say the box is good 40 feet away. My suspicion is that a whole bunch of stuff is tied into the same line that the sound system is on.

It's possible that something in the sound system is failing and picking it up through the electrical line. The frustrating thing is that it only happens when people are in the church. When I am in their by myself it rarely happens.

With $800 and four hours I could re-wire the whole thing but it's not worth it. We are consolidating into another parish and they have a great sound system so their is no use for the equipment.

Thanks
Tom

[cmchamp]

I was going to recommend some SOJ 600w 10/3 hardwired to a new breaker in the panel with the appropriate receptacle at the other end. Ask the electrician about code though.

[tmooney]

We have a church member who is an electrician and I am going to talk with him next week. We can definitely replace the breaker but I can't do anything that is going to cost a significant amount of money. On Wednesday I going in their to find out what is tied into what. One thing I do know is the computer system that runs the bells is tied into the same line which is not a good idea.

I may be able to cut a hole in the floor and run an electrical cable to the basement were I know the outlets are clean and don't have ballasts attached to them. Thanks again.

[Brad Weber]

Originally Posted by tmooney

I am able to create noise in the system by turning off certain fluorescent ballasts in the back of the church. I tested all of the outlets and they are OK but something causes the random noise through the system. Next week I am going to shut off the breaker and see what is tied in. We do have an electrical guy who can replace the breaker if need be.

So the noise appears when the fluorescents are off? If the noise is directly related to the fluorescent light operation then my first guess is something like shared neutrals.

The fact that the noise apparently only happens when the room is occupied means I would also look at the HVAC systems or any fans as possibly being related.

As Cory suggested, I'd be wary of changes to the electrical panel. It sounds like there have already been modifications and additions that may or may not have been properly planned and performed and you probably want to avoid taking 'ownership' of all that by being the last one in there.

[Frank DeWitt]

Does this noise happen only when people are in the room AND something is connected to the sound system that is not there during testing? Guntar, Keyboard, Microphone?

Frank

[tmooney]

The florescents are what tipped me off to the electrical panel. Actually flipping the on and off switch can make the speakers crack in the church, so I am sure the breaker that powers them is tied to the sound system outlet.

To explain the issue related to people in the church is a mystery to me. Basically the cracking is much more prevalent when their is an actual service or rehearsal and the church is filled. Over the past 2 months I have gone in several times and turned everything on and problem does not surface.

The church caretaker has been turning the system on when he is their working by himself and it hardly ever does.

Two weeks ago I went in their and worked for a hour before choir practice and nothing. As soon as the people started showing up and their was thirty people in the church it starting cracking.

I just check a few other things. The organ and piano are on a separate set of speakers. That's how it was wired back in the sixties and it was never changed. The HVAC is on another panel so that is totally isolated.