{HEAD ~ The second transducer} lies in the plane of the input and output transducers of the parent application, but faces {TAIL ~ the ear canal cavity} so that it detects the residual uncancelled noise present inside the ear canal cavity 
faces
{ HEAD ~ The second transducer } lies in the plane of the input and output transducers of the parent application , but faces { TAIL ~ the ear canal cavity } so that it detects the residual uncancelled noise present inside the ear canal cavity
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH