A system and method for actively changing the sound perceived by listeners in an audio environment. A single transducer is used as both a sensing microphone and as an output driver. In one embodiment, the invention is implemented as an active noise cancellation system. The sensed noise signals are phase shifted to provide a cancellation effect, combined with the desired audio program signals, and output to the transducer, thereby reducing the level of unwanted noise heard by they listener. In other embodiments, the system can be used to sense the frequency response of a listening room and make appropriate equalization adjustments to the output.
