Echo cancellation subtracts echo from the near-end signal therefore it works in the presence of double-talk. On the other hand, echo suppression is dependent on echo detection and is not very sensitive to minor changes in the behavior of the echo.Ī double talk is the case where both parties talk simultaneously. Robustness and flexibility to echo behaviorĮcho cancellation needs to calculate the exact echo from the speaker signal, hence any sudden change in echo behavior might lead to a short burst of echo until the echo calculations will be updated to reflect the new behavior of the echo. On the other hand, echo suppression requires moderate processing time. Now, Let us briefly review the major pros and cons of each mechanism.Įcho cancellation requires significant processing time in order to calculate the exact echo image. In such cases usually suppression will provide better results. On the other hand, there are systems in which the behavior of the echo is volatile and prevents a robust calculation of the echo. Therefore, in PA systems the suppression mechanism is usually not a good option. As a result the two signals are too close to be easily separated. Well, each voice system has different characteristics and might therefore require a different behavior in handling the echo.įor example, in many PA systems, the microphone records the near-end speech, and shortly afterwards the returned echo. However, while the AES only needs to detect the echo location, the AEC also needs to calculate the actual echo using the original speaker signal so it can be subtracted from the signal that is captured by the microphone. On the other hand, Acoustic Echo Suppression checks the speaker (far-end) signal and microphone (near-end) signal and when it detects echo, it mutes the microphone signal.īoth AEC and AES needs to detect the echo that the far-end generates. Afterwards, it subtracts the calculated echo from the microphone (near-end) signal.
In this post we discuss the two basic mechanisms to handle echo: Acoustic Echo Cancellation (AEC) & Acoustic Echo Suppression (AES), the main differences between them and how to select the best approach to your project.Īcoustic Echo Cancellation calculates the echo from the speaker (far-end) signal taking into account multiple factors like echo-path, volume levels and distortion.
To familiarize yourself with the basic terms that relates to echo cancellation, you are invited to read our blog-series on echo cancellation. In some cases the echo can even turn out to howling effect that generates a deafening noise. Echo is a known problem in telephony and when it appears it dramatically reduces the quality of the audio.
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