Most fitness instructors experience wireless microphone feedback at some point. Group X managers hear instructor and member complaints such as “the microphone is feeding back,” “there is a loud squealing noise” and “it’s feeding back, making crackling noises and static.” So, what is mic feedback?
Feedback usually refers to the high squealing or low whale-like sounds that occur when a microphone picks itself up through the sound system speakers, thus feeding its own sound back into the speakers repeatedly and creating a feedback loop. It’s an annoying sound that can interrupt a class, especially if it’s persistent.
Lets look at the two most common reasons feedback occurs: Mic system gain (or sensitivity) not set correctly; and speaker placement.
When a transmitter’s gain is too hot, it can make adjusting the mic’s volume on the mixer difficult. To fix this, begin by turning down the “trim” or “sensitivity” of the microphone transmitter (AKA the beltpack or battery pack). A transmitter typically has sensitivity controls inside near the battery, sometimes labeled “db,” “gain” or “trim.” Try turning this control down to as low as possible and see if this helps eliminate the feedback.
Another gain adjustment is sometimes found on the wireless microphone receiver — usually located in the sound system’s equipment rack, or plugged into the mixer. The receiver may have an output selector on the back labeled “mic/line.” If it’s set to “mic,” try switching it to “line.” This will lower the receiver’s output gain and make it more adjustable at the mixer.
A final note on wireless mic adjustment: If the sound system’s mixer has tone controls for the wireless mic channel, adjust the treble down for high-pitched feedback, and adjust the bass down for low-pitched feedback. Sometimes turning down the mic channel volume just a bit on the mixer can do the trick.
If adjusting gain does not cure the feedback issue, check the speaker placement in the room. The speakers should be located on the “instructor wall” (the wall that the instructor has their back to) so the speakers aren’t pointing directly at the microphone. If there are four speakers in the room and two are on the back wall facing the instructor, consider moving these to the side walls, a third of the way down the length of the room and aimed at the back wall, not the instructor.