If you do a search for turboprop noise in the NASA archives you will
find the info - the surprising thing to me was that the noise levels
were about equal clear out to the sixth harmonic. Yes, the XF84H was
loud. But the Saturn 5 was mucho louder, but you couldn't get closer
than about 8,000 yards. OTH, standing about 3 feet to one side from
the nozzle of a J79-17 at max power is verrry interesting.
Walt BJ