Acoustic Echo Return Loss Enhancement – AERLE – The maximum echo cancellation provided by the acoustic canceller. Typical figures will vary from 6 to 18 dB. The larger the number the better. It is important to note whether the figure is quoted with the center clipper enabled or disabled. If quoted with center clipper disabled, it is a true measure of the cancellation provided by the echo canceller rather than the attenuation provided by the center clipper.