Popping Noise on Speakers

[cw4u]

During our sermon yesterday, I heard a distinct pop every now and then coming from the speakers. All the channels were muted except for the pastor. I solo'd his channel on the console...no pop. I plugged my headphones into the wireless receiver...no pop there either. He is using an compressor on the insert of his channel but the solo is post-insert...so even if that was causing an issue, I would have been able to hear it.

Any ideas on what this might be?

[cmchamp]

was it a predictable cycle?
Did someone install a new appliance or office machine?
Did the HVAC cycle coincide with the pop?

[cw4u]

No to all of the above. It wasn't pretty random but did occur every 10-15 seconds I would assume.

[petereit]

Could be a signal path issue between your outputs and the amps, or the amps themselves. Might be a good excuse to do some downtime maintenance on your amps. Be sure to check all high-power circuits for carbon traces that could indicate arcing.

[DTV-Engineer]

Possibly somebody's cell phone sitting near the console or amp? We have the tee shirt for that. We also had the heater for the baptistry injecting occasional pops into one of the powered monitor wedges several years ago.

These are the sorts of problems that explain my short haircut: I'd be pulling it out if I could grab hold of it...

-- Jeff

[cw4u]

I don't think the amps have been de-racked. ha. They might just have to deal with popping for now until my finals are over at the end of the month.

[cw4u]

No GSM phones near any of the equipment. All CDMA...have they been known to cause any sort of noise? I sure have never experienced it before.

The heater wasn't on either.

[DTV-Engineer]

Okay, here's another: our previous church had an aluminum cross on the outside wall, including a light inside that shone against the brick wall, essentially back-lighting the cross rather nicely. This also happened to be wall directly behind the sanctuary platform.

One evening I got a panic call that the sound system was buzzing and crackling and nothing would stop the racket; turns out some bird had made a nest inside the cross and it was a misty evening, so the high voltage for the neon tube was arcing across all this stuff to the metal. The light was on a timer, so it never happened during normal services...

Here at work, I've also had bad fluorescent ballasts (the electronic kind) create periodic popping and buzzing in audio equipment. One trick for locating this sort of interference is to use a handheld AM radio, tuned between stations. The rod antenna is directional, so you can use that to get a feel for where the noise is coming from, and identify where it's strongest.

-- Jeff