Automatic gain control keeps a speaker's voice at a consistent target level regardless of how loudly they talk or how far they sit from the microphone. It continuously estimates the incoming level and applies gain to push quiet talkers up and loud ones down, so a meeting doesn't force everyone to ride their own volume. The challenge is doing this without pumping audible level swings, without amplifying background noise during pauses, and without fighting the other processors around it. In WebRTC the modern implementation is AGC2, which does most of the work with an adaptive digital gain and keeps a separate input volume controller for the microphone slider, giving steadier results across the wildly varying microphones people actually use.
In a microphone or app settings menu, an AGC switch means the same thing: leave it on for calls and meetings, turn it off for music or a studio microphone. Our guide to automatic gain control in mic settings and WebRTC explains when to turn AGC on or off in Zoom, Discord and the browser, and how AGC2 is tuned.
The book · Volume 4 of 7
Audio for Video: A Complete Guide to Sound in Video Products: From PCM and Codecs to Loudness, Accessibility, and Real-Time Voice Processing
AGC keeps quiet and loud talkers at the same level, but tuned badly it pumps noise up during pauses or flattens expressive speech. Volume 4 covers AGC in detail within real-time voice processing: automatic gain control, echo cancellation, noise suppression and VAD, and loudness targets for speech. Written by Nikolay Sapunov, CEO at Fora Soft.
Voices too quiet or pumping in your calls because of AGC?
Send us recordings from real calls, and we will tune AGC settings and check how they interact with echo cancellation and noise suppression. 250+ video products shipped since 2005.
