Play the Velvet Underground’s “Sister Ray” at half-speed — go ahead, do it — and you’ve got Swans plus a sense of humor and the possibility that, if you just adjust the speed control, everything will get good. Take away the sense of humor and the speed control, and you’ve got Swans. In all probability, you’ve also got either a high threshold for crunching pain or a splitting headache. Well, that’s Swans: downtown New York arties, friends of the infinitely more imaginative Sonic Youth. Swans trudge through dragging tempos, 2/2 meters and low frequency mush, all the while howling about alienation and despair. Listening to their records isn’t like banging your head against a wall; it’s like banging your head against the side of a swimming pool — underwater.