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Static When I turn off the mic
Old 3 weeks ago
  #1
Here for the gear
 

Static When I turn off the mic

hey all,
i've recently put together a pa system which consists of
a EV ZLX12BT powered speaker
behringer xr12 digital mixer
and a wireless microphone unit which is the Sennheiser XSW2-835-A

i was testing the system and everything sounded fine , then as soon as i turned off the mic by switching it off on the microphone, the loudest static noise started blasing through my PA speaker.

i have the volume/gain knob on the sennheiser receiver unit all the way up and i think this is what is causing it, but if i turn it down then I can't hear any mic vocals through the PA.

also have input gain on the xair app set to about 50db.
everything was sounding fine, just when iturn the mic off this static comes in and im not sure how to fix it.

appreciate any help i can get, i know its something to do with the way i have the gain structure setup i guessing?
Old 3 weeks ago
  #2
Gear Head
 

Yeah your gain staging is all out of whack. Put everything on the mixer back to it's factory preset and the mic reciever gain at it's mid point(straight up), bring the master fader to unity and then adjust the mic input channel gain so that your vocals are peaking at a reasonable level on the meters, then bring up the fader on that channel to get the volume you want from that mic in the PA.
Also note there is a SQ (squelch) adjustment on the back of the wireless reciever, this functions as a gate to block unwanted noise when the mic is not in use, you may or may not have to adjust this once you have the gain stages set correctly.
Old 3 weeks ago
  #3
Lives for gear
 
JayTee4303's Avatar
Your mic is feeding the receiver a quiet carrier signal, and or controlled modulation, while it's on.

When you turn it off, the next strongest radio signal takes over. No telling who or what that is, but clearly, the sender isn't nearly the audio engineer you are!

Work your squelch, AND change channels. Some are noisy, some are quiet. It depends on your neighborhood.

Then, stop taking chances.

Faders down, THEN mess with mics.

You wouldn't rip all the XLR inputs from your console with the faders up, would you?
Old 3 weeks ago
  #4
Lives for gear
 

Definitely RF, Sennheisers do That when you have RF interference (as was already said). Find an open channel. If you see the RF meter go up at all when your mic is powered off, keep scanning channels until you find one where that doesn’t happen. An RF scan is the most thorough way, but doing what I just said is a “quick and dirty” method to find open channels.

I’m not sure where you’re located, but as the available channels shrink because of bands being sold off, it gets tougher to find clean channels.
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