Double-talk is the hard case for echo cancellation: the moment when both the near and far parties speak at once. An echo canceller works by adapting a filter to model the echo of the far party's voice, but during double-talk the microphone also contains the near party's genuine speech — and if the canceller mistakes that for echo and adapts to remove it, the near voice gets chewed up or clipped. So cancellers include a double-talk detector that freezes adaptation when both are speaking, preserving the near voice while still suppressing echo. Handling double-talk gracefully, without dropouts or half-duplex 'walkie-talkie' behaviour, is one of the main marks of a good AEC.
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
Double-talk is the moment echo cancellers fail in public: both people speak and the near voice gets clipped or the far echo leaks through. This volume treats double-talk in detail as part of real-time voice processing, with AEC, AGC, noise suppression and VAD, so you can tune the whole chain instead of one knob. Written by Nikolay Sapunov, CEO at Fora Soft.
Callers cutting each other off when both talk because your echo canceller handles double-talk badly?
Share a recording of a bad call and we will diagnose the double-talk behavior of your AEC chain and propose tuning or a replacement path. 250+ video products shipped since 2005.
