A sub-MW electromagnetic microspeaker with bass enhancement using a parylene/graphene/parylene composite membrane

This paper demonstrates an ultra-low-power electromagnetic microspeaker where a parylene/ graphene/parylene composite layer is employed as the speaker membrane for not only bass sound enhancement but also for power improvement. The speaker with a ∼500 nm thin composite membrane in a size of 3.5 mm in diameter can exhibit a sound output of 104 dB sound pressure level (SPL) @ 670 Hz in a 2 c.c. coupler with an input power of 380 μW. This composite membrane speaker with the least power consumption performance has shown its great potential for the Completely-in-the-Canal (CIC) hearing aids applications with better battery life.

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