The second input transducer is oriented in {TAIL ~ the opposite direction} from {HEAD ~ the first input transducer} 
The second input transducer is oriented in { TAIL ~ the opposite direction } from { HEAD ~ the first input transducer }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD