US Patent 10506333 Acoustic device

An acoustic device includes a cabinet with a cavity room, a speaker unit mounted in the cavity room of the cabinet, a sealed room formed by the cabinet together with the speaker unit, a predetermined amount of nonpolarity gas which is sealed in the sealed room, a predetermined amount of zeolite absorbent which is sealed in the sealed room and physically absorbing the nonpolarity gas so as to decrease a resonant frequency of the sealed room and increase low frequency resonance of speaker unit.