blueskyrich
many times at KDCA, if you go to the north end of the airport, there is a park called, gravelly point.
sitting there the planes come over your head at much less than 200'.
the sound you mentioned is a very interesting one and is different for each type of plane.
my beloved dc9/md80 gives a very nice sound, sort of a zing, with a sound you might hear in an old science fiction movie.
when humidity is high you can see the vortex slightly.
regards
jon
PS...hitting wake aloft is not unheard of...but for a "training pilot" to not know this concerns me.
to further confuse the issue, mountain wave here in the USA can be felt 700 miles downwind of major mountain ranges.