Vent ports 58 are provided for equalizing air pressure differences between the ear {HEAD ~ facing side} of {TAIL ~ the output transducer diaphragm} 44 and the space between diaphragm 44 and frame structure 47 of the composite transducer structure 100 
of
Vent ports 58 are provided for equalizing air pressure differences between the ear { HEAD ~ facing side } of { TAIL ~ the output transducer diaphragm } 44 and the space between diaphragm 44 and frame structure 47 of the composite transducer structure 100
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH