US Patent 11026012 Earphone including tuning means

An earphone includes a housing, the speaker unit disposed in the housing, a cover coupled with the housing and including a nozzle, a first space portion disposed in front of the speaker unit, and a second space portion disposed in the rear of the speaker unit and partitioned off from the first space portion. Here, the speaker unit includes a cylindrical yoke with an open top, a magnet fixed to a bottom surface of an inside of the yoke, a plate fixed to a top surface of the magnet, a voice coil disposed between an inner circumference of the yoke and outer circumferences of the magnet and the plate, a vibration plate disposed above the plate and to which the voice coil is fixed, a cap coupled with the yoke, and a frame coupled with the yoke and the cap.