Abstract: An apparatus for reducing noise for an interior of enclosed space, e.g., a vehicular compartment using an FIR adaptive digital filter is disclosed in which a control circuit is provided which outputs drive signals to a plurality of loud speakers which generate control sounds to interfer with a noise sound propagated in the interior so that a performance function including terms of residual noise signals output from residual noise signal detecting microphones and drive signals to the loud speakers is minimized and contributivity of the drive signals to the performance function is changed according to an occurrence of divergence in the noise reducing apparatus.

Abstract: A vibration sensor is disposed at an evaluation point on the vehicle floor proximate the driver's seat. This sensor, in combination with one disposed on a electrically controllable engine mount, is used to determine the magnitude and orientation of a vector of vibration which reaches the evaluation point and which combines with other vibrational vectors in a manner which results in the generation of vibration at the evaluation point. A mount control signal is controlled in a manner which modifies the vibration vector and attenuates the vibration at the evaluation point.