Maybe this is a start.
https://physics.stackexchange.com/questions/48251/does-altitude-affect-sound-pitch
https://www.amazon.com/dp/0486602923
On the other hand, OP is denying us her/his experience.
https://physics.stackexchange.com/questions/48251/does-altitude-affect-sound-pitch
https://www.amazon.com/dp/0486602923
On the other hand, OP is denying us her/his experience.

