Due to the sloping of the truncated cones sidewall, {HEAD ~ the gap} 70 gets bigger through {TAIL ~ the length} of the air horn 50 
gets bigger through
Due to the sloping of the truncated cones sidewall , { HEAD ~ the gap } 70 gets bigger through { TAIL ~ the length } of the air horn 50
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH