The only Sviger reference left was using Speed -20 in Centaurium (Centurion [sic])-type versions, could've just worked for Splatoon/Tranquility 1 & 2, Embedded 99xx, Windows v4000/XP6004/Nexus/Windows v4001/Nibiru only...
(The speed parameter was used in Sviger Super Centaurium sounds.)