I not sure how you coded ( or decided) which music sound file was actually triggered as a sound effect or which was flagged as a music file (which can be eliminated by the music volume slider). However, there are many 'music files' that continue to play even though the slider is set to zero volume. For example, the following file: client_sound 11243.ogg (which is the 'ominus' background music) in the new 'live event', is not linked to music but plays as a pervasive sound effect.. while it's nice to hear a couple of times; ( personal opinion/preference) I would prefer that it, and other music files like it, are linked to the music volume slider and therefore can be eliminated from playing if so desired.
Any response from the audio nuts from the dungeon in westwood (a mere 20 mins away as the dragon flies.. tempted to start a quest to explore & loot it), would be greatly appreciated.