Adjustable phrtf adaptive structure

An adjustable phrtf adaptive structure is used in a customized earphone and comprises a unit front cover, a lifting mechanism and a variable-diameter conduit. The unit front cover comprises a cover body, a sound outlet hole is formed in the inner bottom surface of the cover body, a pressure relief opening is further formed in the inner bottom surface of the cover body, and a filter screen groove matched with the pressure relief opening is formed in the outer bottom surface of the cover body. The lifting mechanism is arranged in the unit front cover, and the lifting mechanism is annular and used for fixing the earphone unit on the inner circumferential side of the lifting mechanism. The variable-diameter conduit is arranged at the lower end of the sound outlet hole and used for connecting the resonance cavity. According to the adjustable phrtf adaptive structure, the problem that sound quality is reduced due to the fact that sound heard by users with different ear shapes through customized earphones is differe