Abstract: In a video conference facility, an echo cancelling device is provided which comprises an adaptive finite impulse response filter operable to sample the input signal to a loudspeaker and to model, on the basis of that signal, the signal fed back to a microphone. The echo cancelling device further comprises a combiner for subtracting the model feedback signal from the microphone output signal and to provide a corrected microphone output signal, and a microprocessor programmed to read the corrected and uncorrected microphone output signal and to compute updates to the weights of the filter, the computation including a multiplication by a variable scaling factor which varies in accordance with the ratio of a first value indicative of the long-term average power of the sound being fed back to a second value indicative of the short-term average power of the sound being fed back.