First I tried point sound triggers, then played around with MusicVolumeTriggers too, I was kind of giving up then so haven't tried too many variations, but music resource and bounding box was set, and nothing.
Now I got it to work, though I messed around with quite a lot of things since then, so not sure what made it work. Perhaps dummy chars don't trigger these? Or maybe it just needs Origins referenced for these to play correctly..