How to Eliminate Audio Feedback: Complete Guide

TL;DR

Audio feedback occurs when a microphone picks up its own amplified output. SonaVyx's problem detector automatically identifies feedback-prone frequencies, and the ring-out workflow guides you through systematic notch filtering to maximize gain-before-feedback.

How to Eliminate Acoustic Feedback

Acoustic feedback creates the familiar howling or ringing sound when a microphone picks up amplified sound from a loudspeaker. Eliminating feedback systematically increases your gain-before-feedback (GBF) and overall system headroom.

Step 1: Identify Feedback Frequencies with RTA

Open SonaVyx and navigate to the RTA mode or use the Feedback Elimination workflow. Slowly increase the microphone gain while monitoring the real-time spectrum. SonaVyx's feedback detector identifies frequencies where spectral peaks develop narrow Q-factors greater than 10. These show as bright red markers on the spectrum display. Common feedback frequencies occur where room modes, microphone polar pattern, and speaker coverage overlap.

Step 2: Apply Narrow Notch Filters

For each identified feedback frequency, apply a narrow parametric notch filter on your mixing console or DSP processor. Start with a bandwidth of 1/10 octave (Q around 14) and a depth of -6 dB. Narrower filters remove the feedback frequency while preserving the surrounding audio spectrum. SonaVyx displays a recommended filter table with frequency, Q, and gain for each detected problem. Avoid using wide filters, as they degrade overall sound quality.

Step 3: Re-Test and Verify GBF Improvement

After applying filters, repeat the ring-out test. Slowly raise gain again and observe whether the previously problematic frequencies remain stable. Each properly applied notch filter should yield 3-6 dB of additional gain-before-feedback. If new frequencies begin to ring, apply additional notch filters. Most systems require 5-8 notch filters to achieve optimal stability.

Step 4: Document Results

Store a trace of the final system response and export the filter settings. SonaVyx's Before/After comparison mode shows exactly how much headroom you gained. Use the report generator to create documentation for the client or venue file.