How to Prevent Audio Feedback in Marching Band Performances

Sep 17

A practical guide to eliminating feedback and improving live sound quality

We get it and we’ve all been there. Our mix is sounding full and clear in rehearsal at our home stadium, then, we enter an unfamiliar stadium with a wall, small sideline, or other potential feedback-causing contributors, and…. SCREEEEECH - not exactly the impression we planned on giving to the audience and judges.

Audio feedback can ruin even the strongest marching bands, indoor percussion and indoor winds ensembles in the country. That sudden high or low-pitched squeal or hum disrupts the flow, distracts performers, and draws unwanted attention from judges and audiences alike.

The good news? Most feedback is entirely preventable, or fixable in real time.

This guide explains how to avoid audio feedback in a marching band or indoor percussion/winds performances through better mic placement, speaker positioning, scene management, and EQ usage. Whether you’re a band director, sound engineer, or student tech, these tips will help you deliver a clean, professional sound on the field or stage.

Why Feedback Happens in Live Audio

Feedback occurs when a microphone picks up sound from a speaker and loops it back into the system. This loop amplifies itself until it creates that unmistakable squeal or hum. Understanding this basic mechanism is the first step in preventing it.

Proper Microphone Placement: Break the Feedback Loop

The most common cause of feedback is poor microphone placement.

Position microphones away from speakers to minimize the chance of a feedback loop.
Use cardioid microphones for front ensemble setups. These mics have a directional “dead zone” that helps reject sound from behind them—ideal for live outdoor settings.
Even minor adjustments in angle and height can significantly reduce risk.

Pro tip: Always test microphone orientation during rehearsal to find the optimal position for performance.

Smart Speaker Placement = More Headroom

The distance between microphones and speakers matters more than you think.

Doubling the distance between a mic and a speaker can add 6 dB of feedback headroom.
Never aim speakers directly at microphones.
Avoid placing mics directly in front of the speakers that power them.
Give yourself enough side to side distance with your speakers to avoid microphone bleed.
Ensure the front to back distance of your speakers is in front of the closest mic’d instrument in relation to the audience.

Recommendation: Elevate speakers and angle them away from the mic’d front ensemble through the use of stacked speaker carts.

Identify Feedback Sources Using Your Mixer

Modern digital mixers offer built-in feedback detection tools.

Watch for channel meters that spike—these usually indicate the source of feedback.
Problem mics are often the ones closest to the PA system or pointed incorrectly.
Reduce the pre amp gain on the offending mic or use your EQ to reduce the problem frequency.

Use EQ and RTA Tools to Remove Problem Frequencies

Graphic equalizers and real-time analyzers (RTAs) are essential tools for live audio mixing.

Identify and notch out problem frequencies using your board’s visual display.
Don’t over-EQ—target specific frequency spikes instead of cutting large ranges.
This approach preserves tone and gives you more usable volume and better clarity.

Tip: Sweep with a narrow Q filter to locate and remove feedback precisely (‘Search and Destroy’ method)

Resources: Read more about utilizing Equilization in our EQ In The Marching Arts blog.

Mute Unused Channels: Eliminate “Ghost Mics”

Channels that aren’t in use can still cause feedback if they’re left active.

Mute any inactive mic channels during portions of the show when they’re not needed.
This simple step often resolves half the feedback issues before they start.

Best practice: Program your mixer scenes to automatically mute unused channels between segments.

save and Back Up Your Mixer Scenes After Tuning

Digital mixing consoles let you save presets, but they also save your mistakes.

If a scene was saved during rehearsal while a mic was feeding back, that feedback can potentially return during performance.
Always retune your system, fix any issues, and then resave the scene.

Recommendation: Label clean scenes clearly with a naming convention like “ShowName_Fall2025_NM.”

Volume Discipline: Turn It Down When Necessary

Sometimes the simplest solution is also the most effective.

If one channel is prone to feedback, lower its fader slightly.
A quieter, cleaner mix will always perform better than a louder mix filled with distortion and instability.

Note: Judges value clarity over volume—clean mixes consistently translate more than volume.

Director’s Checklist: Prevent Feedback in Live Performances

Angle cardioid microphones away from speakers
Place speakers farther from microphones to increase feedback headroom
Monitor mixer meters to quickly identify problem channels
Use EQ and RTA tools to notch problem frequencies
Mute unused channels during transitions
Resave mixer scenes after feedback issues are fixed
Don’t hesitate to lower volume levels on problematic channels

Audio feedback isn’t just an annoyance—it could potentially affect scoring (points not gained through loss of clarity of intent), audience perception, and your performers’ confidence. Fortunately, with careful planning, proper gear setup, and smart mixing techniques, feedback can be eliminated entirely.

By managing your microphone placement, speaker layout, and EQ settings, you can deliver a performance that sounds as good as it looks. Keep your focus on musicality—not technical issues—and your marching band will shine during every competition.