Digisonix, Inc.

Nelson Industries, Inc.

Seth D Goodman

Larry J Eriksson

Douglas E Melton

Richard A Hoffmann

Edward R Braun

Kirk G Burlage

An adaptive multi-channel active acoustic attenuation system is provided for attenuating complex acoustic waves. The system includes a plurality of input sensor nodes and a plurality of error sensor nodes. Each node includes a central processing unit and a network interface. A medium physically interconnects each of the network interfaces to a communication module of a controller by means of a control bus or the like. A control network is provided for controlling communication between a communication module of a controller and each of the network interfaces to control the flow of data along the medium.

Transducer daisy chain

An active noise control system is provided for cancellation of noise in a duct. A speaker is mounted over an opening in the duct. An enclosure is mounted the duct about the speaker. Air flow is generated through the enclosure in order to balance the diffusion of water vapor through the speaker such that the dew point of the air in the enclosure is always below the temperature of the air in the enclosure, thus avoiding condensation.

Dry acoustic system preventing condensation

An active acoustic attenuation system and method which operates in a waveguide (i.e. duct or beam) to attenuate acoustic waves having energy in the plane wave node and in higher order nodes. The invention does this by sensing the acoustic wave at linearly independent locations across a waveguide, decoupling the signals to generate an independent signal for each node being attenuated, processing the signal for each node independently of one another, and combining the processed signals for each node to drive a set of actuators at linearly independent locations across a waveguide. The invention is useful for both sound control and vibration control.

Active acoustic attenuation system that decouples wave modes propagating

Detection of higher order mode transverse modal energy is suppressed for an acoustic wave propagating longitudinally through a duct. First and second microphones are placed in respective first and second nodal planes of the second higher order mode, and the outputs of the microphones are summed. For the first higher order mode, the output of the first microphone is equal in amplitude and opposite in phase to the output of the second microphone, and the resultant sum is zero. For the second higher order mode, the output of each of the first and second microphones is zero, and the resultant sum is zero.

Growing community of inventors

Madison, WI, United States of America

Seth D Goodman