To control feedback in live sound, you break the loop between microphones and speakers: keep mics behind and away from the speakers, use directional mics with good technique, set sensible gain, and ring out the system before the show so you can notch problem frequencies before they squeal. Feedback is not bad luck — it is a predictable loop you can manage.
Here is what causes it and the practical steps that keep your gig howl-free.
Why feedback happens
Feedback is a loop: a microphone picks up sound from a speaker, that signal is amplified and sent back out the speaker, the mic picks it up again, and the cycle builds until it rings or squeals. It always starts at the frequency where the loop has the most gain — usually a frequency you have boosted or where the mic and speaker geometry are worst. Break any part of that loop and the feedback stops.
Position speakers and mics correctly
This solves most feedback before you touch a knob. Keep your main speakers in front of the microphones so the mics are in the least sensitive part of the speaker’s coverage. Position monitors so they fire into the null of the mic’s pattern — directly behind a cardioid mic. Keep performers close to their mics; the closer the source, the more gain-before-feedback you get. Our walkthrough on how to set up a PA system covers placement in context.
Use the right mics and technique
Directional dynamic mics (cardioid and similar) reject sound from behind, which is exactly where your monitors are. Encourage singers to work close to the mic and avoid cupping the grille, which wrecks the polar pattern and invites feedback — see how to mic a singer live. Mute channels that are not in use; an open mic no one is using is just a feedback waiting to happen.
Set gain sensibly
Too much gain anywhere in the chain pushes the system toward feedback. Set clean input gain and avoid large EQ boosts, since boosting a frequency makes the loop more likely to ring there. Cutting problem frequencies is almost always safer than boosting — the same logic in how to EQ live vocals.
Ring out the system before the show
“Ringing out” means deliberately raising the gain until the system just begins to ring, identifying that frequency, and cutting it with a narrow EQ band — then repeating to chase out the next one. This raises how loud you can go before feedback starts. Do it for both the mains and the monitors during setup; our guide to ringing out monitors covers the monitor side in detail, and preventing vocal feedback on stage focuses on mics.
React fast when it starts mid-show
When feedback begins during a performance, the quickest fix is to pull down the gain of the channel that is ringing. If you can identify the frequency, a narrow cut there kills it without dropping the whole channel. Many digital mixers have feedback suppression that helps, but treat it as a safety net, not a substitute for good setup — relying on it alone can leave the mix dull.
Quick feedback checklist
- Mains in front of the mics, monitors firing into the mic’s null.
- Directional mics, used close, with unused channels muted.
- Clean gain, minimal boosts, cuts preferred.
- Ring out mains and monitors before the show.
- Pull gain or notch the frequency the instant it rings.
Frequently asked questions
What is the fastest way to stop feedback during a show?
Pull down the gain of the channel that is ringing. If you can spot the frequency, a narrow EQ cut there stops the squeal while keeping the channel in the mix.
Does ringing out the system really help?
Yes. Notching out the frequencies where the system rings raises the level you can reach before feedback starts, giving you more usable volume and a more stable mix all night.
Why do my monitors feed back more than the mains?
Monitors sit close to and often point toward open microphones, which is the worst geometry for feedback. Aim them into the mic’s least sensitive zone, keep their level only as high as needed, and ring them out separately.
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