Active acoustic noise and echo cancellation system

Full acoustic coupling and echo cancellation is provided in implementations where there is acoustic coupling between acoustic zones. In acoustic echo cancellation systems, including active acoustic attenuation systems and communications systems, having a first model canceling the speech of a second person in the output of a first microphone otherwise present due to electrical transmission from a second microphone to a first loudspeaker and broadcast by the first loudspeaker to the first microphone, the cancellation of the speech of the second person in the output of the first microphone preventing rebroadcast thereof by the second loudspeaker, and a second model canceling the speech of the first person in the output of the second microphone otherwise present due to electrical transmission from the first microphone to the second loudspeaker and broadcast by the second loudspeaker to the second microphone, the cancellation of the speech of the first person in the output of the second microphone preventing rebroadcast thereof by the first loudspeaker, an improvement provides a third model cancelling the speech of the first person in the output of the first microphone otherwise present due to acoustic transmission from the second loudspeaker in the second zone to the first microphone in the first zone, and a fourth model cancelling the speech of the second person in the output of the second microphone otherwise due to acoustic transmission from the first loudspeaker in the first zone to the second microphone in the second zone. Further improvements and features are provided in various combinations.