While out of combat background music plays, this could change depending on where you are and what realm you are in. Once combat tagged the music turns from idle to intensive but this could obviously be done using a gradient where it ramps up in intensity depending on how long you have been fighting for. Once a domain is used the theme song related to the tech could play (this could be overwritten with custom domain soundtracks)This music could also change depending on what tech initiated combat with you or change depending on a specific curse/mob you are fighting with priorities for songs being given to avoid stacking music if you fight multiple named mobs.

If its requested enough it could also have a toggle to turn this feature off if its too loud, overwhelming, or you just don't wanna listen to it.