After detecting the residual noise, the second input transducer outputs a signal to the electrical circuitry in the control unit of the invention so that an opposing sound wave 180° out of phase with the residual noise will be input into {HEAD ~ the ear canal cavity} by {TAIL ~ the output transducer} 
by
After detecting the residual noise , the second input transducer outputs a signal to the electrical circuitry in the control unit of the invention so that an opposing sound wave 180 ° out of phase with the residual noise will be input into { HEAD ~ the ear canal cavity } by { TAIL ~ the output transducer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL