🚀 go-pugleaf

I was wondering if there exists a fairly simple physical explanation
of what would happen to a white sound packet as the density of
air decreased (ie go up in altitude). Obviously in the limiting case
the amplitude of sound would decrease to zero, but are certain
frquencies attenuated more quickly by decrease in air density than
others?

As well, what happens at fixed air density but variable relative
humidity? Are certain frequencies attenuated more quickly than others?

From such information I would like to "predict" what would happen
to the sound of various musical instruments if they are played in
a humid or dry environment or if played a sea level, or the top
of a mountain.

Any ideas in this query would be appreciated!