An active acoustic noise reduction system which comprises a single input
transducer and an output actuator that are physically located next to
each other in the same location. In one embodiment, the input transducer
and the output actuator are a hybrid represented by a single element. The
active noise reduction system is located as close as possible to the
noise source and functions to generate an antinoise cancellation sound
wave with minimum delay and opposite phase with respect to the noise
source. The noise reduction system also comprises a non linearity
correction circuit, a delayed cancellation circuit and variable gain
amplifier. The system provides user control of the quiet zones generated
by the system by varying the gain of the variable gain amplifier. The
system provides a user with the ability In one embodiment, an echo
canceler is utilized to remove echoes fed back from the output actuator.
In another embodiment, an input decoder is used instead of an echo
canceler to remove feedback picked up from the output actuator.