Active bass trap

Active bass trap is a type of bass trap that uses electronic sensing and actuation to reduce low-frequency sound energy and room mode resonances.

Unlike conventional active noise-cancellation systems, which generate a secondary sound field to produce destructive interference, active bass traps absorb acoustic energy by controlling the acoustic impedance at the absorber. In impedance-controlled systems, lowering the acoustic impedance presented to the surrounding air allows more low-frequency energy to be absorbed rather than reflected into the room.

The acoustic impedance of the loudspeaker diaphragm can be controlled by electrical or electronic means, changing the way the transducer interacts with the surrounding acoustic field. By selecting an appropriate impedance, the absorber can dissipate acoustic energy over a desired low-frequency range.