I think Americans such as Leviathan have done a lot to expand the sonic palette of black metal.
Colin MarstonThe term "black metal" has become a lot looser, or can include a larger range of sounds and extra-musical aesthetics, not just Satan and power chords.
Colin MarstonI've never had a band with more than 3 people (meaning only two string players), so I love having the ability for 3-part polyphony.
Colin Marston