Abstract: The invention relates to a sensor apparatus (30) operable to receive and process acoustic signals. The sensor apparatus comprises at least one acoustic transducer (32) operative to produce a change in an electronic output signal in response to receipt of an acoustic signal by the acoustic transducer. The sensor apparatus also comprises processing circuitry (34) configured to receive a first electronic output signal and a second electronic output signal produced by the at least one acoustic transducer. The processing circuitry is operative to shift a phase of the first electronic output signal and the second electronic output signal in relation to each other. The acoustic transducer and the processing circuitry of the sensor apparatus are juxtaposed such that they form a unitary body.