This invention relates to electroacoustic devices for performing noise cancellation, communication interfacing, {HEAD ~ sound filtering}, and headphone functions for {TAIL ~ the human ear} 
This invention relates to electroacoustic devices for performing noise cancellation , communication interfacing , { HEAD ~ sound filtering } , and headphone functions for { TAIL ~ the human ear }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL