Acoustic signal cancelling

An acoustic signal cancellation system is configured to perform: (a) provide a user device, associated with the system, and an audio capture device. (b) receive at system a captured signal indicative of a captured acoustic signal. It's received at capture device, and comprises a second acoustic signal generated by a second device, external to user device. (c) receive, from external source, a reference signal, indicative of a content included in the second signal. (d) in a case that a content of reference signal and the content in second signal are not time-synchronized, generate a synchronized reference signal, based on reference signal. Content of synchronized reference signal and second signal content are time-synchronized. (e) perform acoustic signal cancelling of that portion of captured signal which corresponds to second signal, based on reference signal. Generate reduced signal. This facilitates output of reduced signal to third device.