Microphones - Feedback Question

[salsa88]

I'm working in a 3 part ballroom and have been getting some feedback lately. The 3 parts can be combined i.e. 1+2, 2+3 and 1,2,3. The feedback comes even when I don't have anything plugged into the wall pockets in the ballroom. I have two questions.
1- What could be cussing the feedback
2- Where can I download different frequency sounds to help me id the feedback? i.e. 1k 1.6k 5k and so on so I can properlly EQ the feedback.
Thanks!

[Grog12]

Define don't have anything plugged into the wall panels. No monitors? No microphones? Give us a little more info.

[salsa88]

Originally Posted by Grog12

Define don't have anything plugged into the wall panels. No monitors? No microphones? Give us a little more info.

by wall panels I meant the "Wall pockets".

The sound system in the ballroom has Crown power amps with Crestron wall panels (located in our amp room) The ballroom also has a wall panel with 6 pre programed music buttons and a Mic button with Volume controls. Our "floor/Wall pockets" have 2 mic and 2 line in/outs in each pocket. I'm getting feedback when we do or don't have our mics, mixers and so in connected into the wall/floor pockets and the music is off in the ballroom. I believe our power supplies might be to weak for the wall panels.

[Eboy87]

Huh? I still have no idea what you're trying to say. You're saying you're getting feedback even with nothing plugged in? I'm lost.

[cutlunch]

It may seem silly and not work but check the volume control on the mic pocket to make sure it is not up. Even with nothing plugged in but the volume up on the mic input any noise generated by interference may be getting amplified. This would be rare and only likely if the mic was getting interference from a speaker lead.

Do you have the wiring diagrams for this setup. I take it you have some form of programmed audio distribution system do you have the correct list of what each button is meant to do. Has anyone reprogrammed it lately? Was there a test button included to send a test tone through the system eg 1KHz. Does the feedback occurr as son as you switch the speakers on?

Does the feedback go away when you plug anything into the mic / line pockets.

I would start by checking the system diagrams.
But also I would start pulling cables out starting with the amplifiers.
Pull the input leads out of the amplifiers and turn checking for feedback.
Then plug the leads back in feedback still there?
Disconnect the leads to the amplifier at the end furtherest from the amplifier check for feed back.
Keep working this way back up to the mic / line pockets this should isolate the problem.
Double check any signal processing equipment that is connect after the mic/ line pockets for any test signals any one might have accidentaly turned on.

A more detailed list of every piece of equipment in the audio chain with make and model number may help us to help you.

[museav]

Originally Posted by salsa88

I'm working in a 3 part ballroom and have been getting some feedback lately. The 3 parts can be combined i.e. 1+2, 2+3 and 1,2,3.

Does this combining have any impact on the problem or is this just to give a better picture of the application?

The feedback comes even when I don't have anything plugged into the wall pockets in the ballroom.

If you do not have an open mic in the room then the problem is probably not feedback. Feedback requires a closed loop system and for an audio system the speaker to room to mic path is typically part of that loop. Without that path you do not have a closed loop and thus it is probably not feedback.

I have two questions.
1- What could be cussing the feedback
2- Where can I download different frequency sounds to help me id the feedback? i.e. 1k 1.6k 5k and so on so I can properlly EQ the feedback.

It sounds like right now you are cussing the feedback! As noted above, from the description it does not sound like the problem is actually feedback.

Tell us a little more about the system. You mentioned the input panels being Crestron panels, are they perhaps iMedia or QuickMedia input panels? Are the mics actually part of the Crestron system audio or separate from it? What do you have for mixing and signal processing? How are the signal routed?

[airkarol]

Originally Posted by salsa88

Where can I download different frequency sounds to help me id the feedback? i.e. 1k 1.6k 5k and so on so I can properlly EQ the feedback.
Thanks!

Simple Feedback Trainer

Simple Feedback Trainer. :D

[museav]

It doesn't seem like any further information has been provided, has the problem been resolved?

[salsa88]

Originally Posted by museav

It doesn't seem like any further information has been provided, has the problem been resolved?

The problem has not been resolved
I will post with more info on the setup as we have been very busy with clients and have not had enough time to find the plans and installation setup for the ballroom yet.

[RESERVED FOR MORE INFORMATION]