Did you press the LMB during the race? That will mute the music. otherwise, I don't know, I run on FS-UAE, WinUAE & real hardware and all have sound. It's using Frank Wille's ptplayer
Yes, it's normal you can drive off road for a few secs at start and after a crash.
Solved using WHDLoad default 3.1 slave to launch the game...
Here Amiga DOCs and icons (ColorIcons) I made for your game: mona_hex.lha
REQUEST: Pause key, ESC to quit instead of RMB.