For completist information, Stardust Amiga and Stardust STe got different musics on tunnel sequences.
All original Amiga tunes have been composed by Risto Vuori (RIB/Bloodsuckers). Check "sd*" and "stardust*" here : http://amp.dascene.net/detail.php?detai ... &view=6232
STe specific tunnel tunes have been composed by Tero Kostermaa (Teque/Armada). Check "sdst*" here : http://amp.dascene.net/detail.php?detai ... &view=7347
I guess the mod replay routine used on STe for the tunnel sequences doesn't implement "volume" tracker commands (Cxx & Axx), which are most certainly CPU intensive without the Amiga PAULA sound processor.
Because both STe and Amiga tunnel tunes use 3 channels, but no volume command is used in the STe tunes.
[EDIT] It seems my assumption is correct, reading Teque own website : http://teque.planet-d.net/music_game.htm
Specs V1: Ye olde 15inst mod format
All songs share same sample set
3rd ch only one sample w/offset fx
4th channel used for game sfx
Specs V2: Same as above
Except no volume commands allowed...
Then also using a fixed frequency sample on channel 3 (the "Prodigy" beat sample).