If comedian Martin Mull’s much-misappropriated saying “Writing about music is like dancing about architecture” holds any weight, attempting to sum up the equally ecstatic and obliterating experience of witnessing Sunn O))) at their most potent feels a bit breakdancing about brutalism or trying to riverdance about Mycenaean revivalism. Trickier still, trying to make anything resembling a few vaguely coherent mental notes for the purpose of this review (which, for this writer, proves an experiential trek veering between total oblivion and wildly fluctuating interior monologue) is a laughable prospect – the tripped-out, coeliac plexus-crushing equivalent of the tail trying to wag the dog.…