Patent attributes
A noise reduction system for a device having a noise generating subsystem includes a Helmholtz resonator and a controller. The Helmholtz resonator is disposed in fluid communication with the noise generating subsystem, and includes an active material responsive to a control signal that adjusts a dimensional characteristic of the Helmholtz resonator in such a manner as to affect a resonance characteristic of the Helmholtz resonator. The controller is responsive to an operational characteristic of either the device or the noise generating subsystem to produce the control signal. In response to the operational characteristic, the control signal serves to affect the resonance characteristic of the Helmholtz resonator in such a manner as to reduce a noise arising from the noise generating subsystem, or create a desirable sound quality alteration.
