An acoustic characteristics changing device includes a frame member disposed in an acoustic energy field, electro-acoustic conversion means attached to the frame member to constitute at least a portion of the device, variable impedance means connected as an electrical load to the electro-acoustic conversion means, and impedance control means for controlling an equivalent impedance of the variable impedance means. The equivalent impedance is variably controlled, so that an acoustic impedance and then its decrease frequency or decrease amount can be electrically, continuously and finely controlled.
