Apparatus, methods and computer programs for reducing echo

An acoustic echo cancelling filter obtains an echo path 109 delay estimate 403 and information 405 indicating how many future (lookahead) audio frames it will use, then generates an echo-cancelled signal for the current frame at a time-frequency filterbank 415 (eg. Short Term Fourier Transform or overlap-add filterbank). A time shift between consecutively processed frames is also obtained and used alongside the path delay and number of frames to determine a first delay 413 for a loudspeaker signal 107 and a second delay 419 for a microphone signal 111 to reduce echo and increase intelligibility.