Control of Antiresonance by a Variable Damping Active Resonator.

Adaptive-Passive Noise Control With Self-Tuning Helmholtz Resonators

“…Active resonators utilize a loudspeaker or other active acoustic actuators in the resonator cavity. For example, Matsuhisa et al MTS93] have used an active Helmholtz resonator to suppress tonal noise in duct systems. A loudspeaker in the resonator cavity was used to decrease resonator damping, which increased the amount of attenuation provided by the resonator.…”