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