The second input transducer supplies an electrical signal corresponding to {HEAD ~ the residual noise} to {TAIL ~ the control circuitry} to cancel the residual noise 
to
The second input transducer supplies an electrical signal corresponding to { HEAD ~ the residual noise } to { TAIL ~ the control circuitry } to cancel the residual noise
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH