ERLE (Echo Return Loss Enhancement) is the decibel measure of how much echo an echo canceller actually removes — the difference between the echo level entering the canceller and the echo level left in its output. A higher ERLE means more echo suppressed: figures of 20-40 dB or more indicate a strong canceller. It is the headline metric engineers use to evaluate and tune AEC implementations, often plotted over time to show how fast the filter converges after a delay change and how it holds up during double-talk. ERLE captures only the echo reduction, so it is read alongside speech-quality measures to ensure the canceller isn't winning on echo by damaging the near-end voice.
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
ERLE is the number that tells you whether your echo canceller is actually removing echo or just hiding it under suppression. This volume covers ERLE in depth as part of acoustic echo cancellation, with AGC, noise suppression and VAD, so you can measure and compare AEC builds instead of judging them by ear. Written by Nikolay Sapunov, CEO at Fora Soft.
Need hard ERLE numbers to compare echo cancellers before shipping your calling app?
Tell us which devices and AEC builds you are testing and we will set up an ERLE measurement rig with a comparison report you can act on. 250+ video products shipped since 2005.
