Feedback is a loop: the microphone hears the speakers, sends it back to the speakers, and the loop gains energy until it squeals. Headphones break the loop instantly.
Mic Feedback: the full method
- Put on headphones
Feedback needs a loop from speaker to microphone. Headphones break it instantly and permanently.
- Lower the output volume
If headphones are not an option, reduce the speaker level until the loop no longer sustains itself.
- Increase the distance
Move the microphone away from and behind the speakers so it captures less of their output.
- Point the microphone away
Directional microphones reject sound from behind. Aim the rear of the mic at the speakers.
- Turn on echo cancellation
For calls, browser echo cancellation is designed for exactly this and works well at moderate volumes.
- Check who else is in the room
Two people in one room joined to the same call is the most common cause of meeting feedback. Everyone but one should mute or wear headphones.
Types of feedback and how they present
- Robot warble on callsEcho cancellation fighting a loop it cannot fully remove. Headphones fix it.
- Rising squealClassic acoustic feedback. The loop gain is above one, so the sound builds until something limits it. Reduce volume or distance immediately.
- Low howl or rumbleFeedback at a low resonant frequency, often through a desk or table. Isolate the microphone from the surface.
- Echo of your own voiceNot feedback but latency in the return path. It is a delay problem, not a gain problem.
Feedback is arithmetic
A feedback loop sustains when the sound leaving the speaker arrives back at the microphone at least as loudly as it started. Everything that reduces that return level — distance, direction, volume, absorption — pushes the loop below the threshold and the squeal stops.
This is why headphones are not merely a workaround but the actual solution: they reduce the return path to essentially zero. Every other measure just moves the number closer to the edge, which is why feedback so often returns the moment someone turns the volume back up.
Frequently asked
Can feedback damage equipment?
Sustained loud feedback can damage speakers and hearing. Cut the volume rather than waiting for it to settle.
Why does it start when someone joins a call?
A second device in the same room adds a new speaker-to-microphone path, closing a loop that was previously open.
Is it safe to monitor with speakers?
Only at very low volume with a directional microphone pointed away. Headphones are the practical answer.
Does noise suppression stop feedback?
No. It reduces steady background noise. Feedback is a gain loop and needs the loop broken.
Related tests
Related guides: a complete audio check, testing on Ubuntu, or the Linux and PipeWire guide.
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