An hearing prosthesis configured to cancel received bone-conducted sound. The hearing prosthesis comprises: first and second matched microphones configured to be implanted in a recipient in a spaced arrangement such that the first microphone receives air-conducted sound signals and bone-conducted sound signals substantially simultaneously, and wherein the second microphone receives bone-conducted sound signals at substantially the same time as the first microphone and receives the air-conducted sound signals after a time delay. The time delay results in a relative phase difference between the air-conducted sound signals and the bone-conducted sound signals received by the second microphone. The prosthesis also comprises a noise cancellation system configured to cancel, based on the phase difference, the bone-conducted sound signals received by the first and second microphones.