Optimization of electroacoustic resonators for semi-active room equalization in the low-frequency range

At low frequencies, standing waves within the room cause large frequency-response variations in the listening environment, such as audio rooms or recording studios. This unwanted phenomenon has a significant impact on the sound quality of an audio system. Unfortunately, state-of-the-art soundproofing solutions cannot efficiently handle such low-frequency sound energy. To alleviate this problem, electroacoustic resonators can be used to damp room modes. This concept is based on the connection of direct-radiator loudspeakers to synthetic electrical loads allowing the passive dissipation of a certain part of the incoming acoustic energy of the sound field. Through judicious control of acoustic impedance depending of the placement of the electroacoustic resonators in the room, a significant damping of the dominant natural resonances can be achieved in order to meet the specifications of audio reproduction. This paper investigates the optimization and the spatial arrangement of electroacoustic resonators with a view to damp the low-frequency acoustic resonances in enclosed spaces.