A system comprising a microphone arranged to capture sound from an environment, and an ultrasound emitter configured to emit an emitted ultrasound signal into an environment. The microphone is arranged to capture a received audio signal from the environment, comprising a component in the human audible range. The microphone is also arranged to capture a received ultrasound signal comprising reflections of the emitted ultrasound signal, or else the system comprises another, co-located microphone arranged to capture the received ultrasound signal. Either way, the system further comprises a controller implemented in software or hardware or a combination thereof, wherein the controller is configured to process the received audio signal in dependence on the received ultrasound signal.