Finally listening to Earth's Angels of Darkness, Demons of Light I, soon to get the second part. Led by its only constant member, Dylan Carlson, the band has gone through two stages: the first, in the 1990's, concentrating on drones; the second, since the early Aughts, still lets loose plenty of drones, but they're pulsating in the background (on these newer albums, for example, played by a cellist) alongside subtle rhythmic backing from the bassist and drummer. Repetitive guitar parts (slowly repetitive) are in the foreground.
The music becomes a regular part of your environment, like electrical wires, undulating as they're pulled up then let loose to hang again. Little features change.