Troubleshooting
Feedback
That ring or squeal is a mic hearing a speaker in a loop. It usually rings for a second before it screams — that ring is your warning. Act on it before it takes off.
Pull the offending channel down. Don't diagnose first — get it under control, then figure it out.
If you know which mic it is, pull that channel or its DCA down fast. If you don't, pull the vocals DCA (or the main fader) down a few dB to break the loop, then hunt.
Feedback is a runaway loop. Breaking it anywhere stops it. Questions come after.
Which mic is it?
It's almost always the one that just changed:
- A mic someone just moved or pointed toward a speaker or wedge.
- A channel you just turned up or boosted with EQ.
- A handheld carried in front of the mains.
- An open mic nobody's using — it's still feeding the loop. Mute it.
The pitch of the ring is a clue too: a low howl is low-frequency, a high whistle is high-frequency. That's where the EQ fix lives.
Stop it coming back
Lower the gain, don't chase the ring with more volume. If a channel rings the moment you get it loud enough to be useful, you're at the edge of feedback — this is "gain before feedback," and the fix is less open-mic level, not more.
Bigger picture, in order of impact:
- Turn the stage down. Loud wedges and amps are the usual root cause in a small room. Quieter stage = far more headroom before anything rings. In-ears help a lot.
- Mind mic placement. Keep mics behind the mains, and out of the direct line of monitors.
- Close unused mics. Every open mic is another feedback path.
- Don't over-boost EQ. Boosts are the fastest route to feedback. Cut, don't boost.
Ringing out a mic (before the service)
If one mic is always on the edge:
- Bring that mic's level up slowly until it just starts to ring.
- Note the pitch. Use the RTA on the EQ page to find the exact frequency. EQ + RTA →
- Pull that frequency down with a narrow EQ cut.
- Bring the level up again — it'll ring at a new frequency, higher up. Repeat once or twice.
- Stop once you've got usable level with margin to spare. Don't chase every frequency — a couple of cuts buys plenty.