Or: “What is feedback? And what can I do about it?”
Frequently in movies someone will walk up, tap a microphone and it squeals. That squealing sound is a miniature version of feedback.
Feedback is probably the most common event audio problem. It’s typically an extended, high pitched squeal or wail. Feedback is a loop: Sound goes into a microphone, it’s made louder and comes out a speaker, and then goes back into a microphone, made louder again, comes out the speaker, and so on.
What can you do about it quickly in a jam?
- Move any microphones (and the presenters carrying them) away from speakers.
- If it’s painfully loud you can turn the microphones off or turn the volume all the way down.
But the best way to deal with feedback is prevent it from ever happening. Your AV partner is key in making the appropriate arrangements well in advance.
- The placement of speaker cabinets in relation to microphones can reduce feedback. Simplifying broadly, speakers should project away from where microphones will be.
- The caliber of equipment makes a difference. Quality amplifiers, speakers and microphones will perform well when low quality equipment placed in exactly the same configuration will feed back.
- An equalizer properly set up by a technician can help greatly in reducing trouble frequencies.