Would it be possible to factor prop (eng) sound in relation to airspeed?
Example: nose over into a dive and the faster you go the higher pitch the prop noise. Zoom up in a climb, and as your airspeed goes down the pitch of the prop noise drops.
This might give a better "seat of the pants" feel as to how your plane is doing in relation to TAS, and onset of departure or compression.
Thanx,
Weave