Acoustic echo cancellation removes the far party's voice — played out of your loudspeaker and picked up again by your microphone — from your outgoing signal, so they don't hear themselves echoing back. It works by taking the loudspeaker signal as a reference and using an adaptive filter to model the room's echo path, then subtracting that estimate from the mic input. The hard parts are double-talk (both people speaking at once, where the canceller must not chew into the near voice) and nonlinear or drifting echo from cheap speakers, which a residual-echo suppressor mops up. AEC is the first stage of every conferencing pipeline; without it, speakerphone calls become howling feedback loops.
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
AEC is the feature users notice only when it fails: echo, clipped double-talk or a voice that ducks in and out. Volume 4 covers AEC in detail within real-time voice processing: acoustic echo cancellation, automatic gain control, noise suppression and VAD, and how they interact in a calling app. Written by Nikolay Sapunov, CEO at Fora Soft.
Users hearing echo in your calls despite AEC being on?
Send us recordings from affected devices, and we will find why AEC fails and propose fixes for the capture chain and processing settings. 250+ video products shipped since 2005.
