INVISIBLE ACOUSTIC SCREEN FOR OPEN-PLAN OFFICES AND THE LIKE

The invisible acoustic screen for reducing sound leakage from handsfree telephones, loudspeaking computer terminals, and the like in a workspace includes a sound reducing apparatus comprising: a sound producing loudspeaker; a cancelling loudspeaker; a sensing microphone having an output; a delay circuit; and, an adaptive filter circuit having a value determined by a transfer function between the sound producing loudspeaker and the sensing microphone and by a transfer function between the cancelling loudspeaker and the sensing microphone; and the output of the sensing microphone being fed back to the adaptive filter circuit; and the received signal coupled through a delay circuit to the sound producing loudspeaker.