Earbud-type earphone modeling and measurement by head and torso simulator

This paper presents an analytical model using equivalent circuit method to design an earbud earphone. The electroacoustic parameters of a miniature loudspeaker are measured through a laser triangulation method. Design configurations are analyzed in accordance with the open and closed states of vent and sound holes of earphone. The equivalent circuit model is validated by the head and torso simulator measurements in an anechoic chamber. The effects of vent and sound holes on frequency response are examined and elucidated. The vent and sound holes found to affect the fundamental resonance frequency, low, and medium frequency response. The effect of sponge cover over the earphone’s front side is also investigated. Finally, it is concluded that the sponge can elevate the sound pressure level to 120 dBSPL and above, raising the possibility of permanent and incurable hearing loss. The major contribution of this work leads to successful development of earbud earphone.