a flexible diaphragm sealed over {TAIL ~ the open mouth} of the housing to define {HEAD ~ a plenum} between the walls of the mouth in the housing and the diaphragm, and wherein the inlet formed in the housing is in communication with the plenum 
a flexible diaphragm sealed over { TAIL ~ the open mouth } of the housing to define { HEAD ~ a plenum } between the walls of the mouth in the housing and the diaphragm , and wherein the inlet formed in the housing is in communication with the plenum
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD 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