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

Abstract

At low frequencies in listening rooms, standing waves cause large frequency-response variations within the whole space. These unwanted phenomena have a significant impact on the sound quality of an audio system rendering. 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, and 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 sound reproduction. This paper presents the design of prototypes of electroacoustic resonators and investigates their optimization and spatial arrangement in the perspective of semi-active room equalization.