What’s this noise?

[Brenden Friedel]

Anyone idea what this noise could be. Not the cable or microphone. It is plugged into 1 of 3 inputs backstage that makes the same noise. The others that surround the theatre do not make the same noise. Not a wireless interference either. the connector is a wall plated XLR female shielded that runs underground to a snake. From what ive seen the snake is some sort of weird connectors. It looks like a ton of ethernet chords being plugged into a wall plate.

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[FMEng]

It sounds like common hum that's running through an expander/gate. The expander might be on the console channel or elsewhere in the chain. The hum usually indicative of an open or absent shield, or poor twisting of the pairs.

There are some XLR to RJ-45 snake boxes and wall plates that will perform badly if the wrong type of cable is used. It is supposed to be shielded Cat 5/6 cable with grounding connectors. Using RJ45s for analog audio is a poor and unreliable method for lazy installers. Get some proper cable and connectors, and warm up the soldering iron.

 

[Brenden Friedel]

It sounds like common hum that's running through an expander/gate. The expander might be on the console channel or elsewhere in the chain. The hum usually indicative of an open or absent shield, or poor twisting of the pairs.

There are some XLR to RJ-45 snake boxes and wall plates that will perform badly if the wrong type of cable is used. It is supposed to be shielded Cat 5/6 cable with grounding connectors. Using RJ45s for analog audio is a poor and unreliable method for lazy installers. Get some proper cable and connectors, and warm up the soldering iron.

Ill take a look later to make sure its shielded but the thing that troubles me is that only one of them was fixed, so why do all 3 humm?

 

[MNicolai]

Ill take a look later to make sure its shielded but the thing that troubles me is that only one of them was fixed, so why do all 3 humm?

Anyone's guess without closer inspection, but photos of panels, insides of back boxes, and insides of connectors are useful.

Sometimes it's the panel that the new guy soldered.

One thing to keep in mind is that anything that goes underground, especially in Florida, is going to get wet. Doesn't matter if it's in PVC or RMC pipe -- either condensation or water is going to get into those pipes and flood them. If the cables aren't designed for wet use, they can work for a few years before they begin to deteriorate physically and in signal quality.

 

[JD]

"is a wall plated XLR female shielded that runs underground to a snake."
Check for water intrusion in the conduit. One fast test is to take a fish and run it down the conduit, pull it out and see if it is dry. I have also run into cases where the fish comes back with a bit of nesting material indicating mouse activity, usually on larger conduits.
If either is found, use plenum cable as a replacement. The critters don't like to chew that as much, and it tends to hold up in a wet environment.

 

[Brenden Friedel]

"is a wall plated XLR female shielded that runs underground to a snake."
Check for water intrusion in the conduit. One fast test is to take a fish and run it down the conduit, pull it out and see if it is dry. I have also run into cases where the fish comes back with a bit of nesting material indicating mouse activity, usually on larger conduits.
If either is found, use plenum cable as a replacement. The critters don't like to chew that as much, and it tends to hold up in a wet environment.

I can try that. I don't really know where it leads out to or how long it is. I'm working to get a wire diagram for our theatre