Ask the Expert – how to prevent audio feedback in church

At our live Ask the Expert session Chanton Marlo Petersen asked:

“What is the best way to prevent feed back in our church service?”

Tim Horton, SFL:
Feedback occurs because we ask too much volume from a specific channel. Speaker placement is critical in this too, but often it’s down to the type of mic you use. For example, the things that feedback quickest are tie-clip / lavalier and lectern mics. Change the tie-clip to a headset and I promise you, you will get significantly better gain before feedback. If people can use a handheld radio mic (for example) instead of a lectern mic that’s also good. The principle is to get the mic as close as possible to the mouth of the speaker.

Every time you double the distance between mic and mouth you half the volume capability! Lectern mics and tie clips are inherently at least 6-inches from the mouth; swap the mic if possible and get the distance from mic to mouth as minimal as possible and you’ll find increased volume on tap.

On a similar note, don’t try to ask too much out of a speech mic. Too many people think the spoken word mics need to be the same volume as the music; they don’t. Really it only needs to be slightly louder than normal conversational speech level. Too loud and people switch off…

Chanton Marlo Petersen:
Ah this means a lot. Thank you guys as we seem to encounter this problem often during our church services. Part of the problem I think is that no one in church is really trained in sound.

Geoff Boswell, Audioplan:
In that case ask another local church that has sound team to maybe help you.

Chanton Marlo Petersen:
Never thought of this. Thanks a lot.

Anthony Lear:
Feedback is always an interesting one. Speaker placement, eq and also the use (certain mics certain jobs) and selection of microphones in the right way all have an impact. Another impact is too much gain. Gain is very different from volume and alters the amount of signal coming into the console. Use as little gain as required don’t just turn up the gain for more volume. Only increase for low signal.