An in-the-ear electroacoustic transducer is constructed to limit the effect of accretion of cerumen on acoustically active surfaces: to prevent cerumen from plugging passages for acoustical energy to the tympanic membrane and to facilitate the removal of cerumen from the transducer by the user. A casing...http://www.google.es/patents/US5220612?utm_source=gb-gplus-sharePatente US5220612 - Non-occludable transducers for in-the-ear applications
Non-occludable transducers for in-the-ear applications
