A seat (5) includes a sensor (21) mounted on the seat which is arranged to sense the presence of an object, or movement or position of an object in a non-contact manner, within a sensing region around the seat. A processor is arranged to receive an audio signal and to process the audio signal based on presence, movement or position detected by the first sensor. A processed signal is delivered to a vibro-acoustic transducer mounted within the seat. The processor can also control a lighting effect based on presence, movement or position detected by the first sensor. A user can interact with audio in a personal way, to suit the mood of the user. A seated user can move their body (especially arms or hands) to modify audio, such as music. The seat has a nodule (12) which, in use, fits between the legs of a seated user. The nodule can house the sensor (21) and user controls.