Modifying the Audio
From Elite Wiki
The audio for Oolite is contained in two folders:
$PROGDIR/ Oolite.app/ Resources/ Music/ <-- Music lives here Sounds/ <-- Sound effects live here
The sound files are 44 kHz, ~100-120 Kbps, Oggs. [.ogg is an open source compression and container format. ]
Audacity is the most popular free and open source audio editor.