Thanks!
Well spotted, but actually your CD burner software will automatically convert the tracks - regardless of format or kHz - to "Red Book audio" which is the audio standard for compact discs that the CD32 can play.
The music problem is likely caused by the CD driver (CDTV driver) still present on the (stable) version of Scorpion Engine that I used. Recent experimental versions of the engine dropped it and use only the CD32 driver, so it apparently fixes it. But other issues were added to other parts of the game that need to be dealt it.