A method for cancelling/reducing acoustic echoes in speech/audio signal enhancement processing comprises using a received reference signal to excite an adaptive filter wherein the output of the adaptive filter forms a replica signal of acoustic echo; the replica signal of acoustic echo is reduced adaptively by multiplying a gain to get a gained replica signal of acoustic echo wherein the gain is smaller in speech area and/or double-talk area than non-speech area; the gained replica signal of acoustic echo is subtracted from a microphone input signal to suppress the acoustic echo in the microphone input signal.