If I had to summarize Sleigh Bells’ sound in one word, I would say ‘chaotic’. Not in the sense that they don’t know what they’re doing or don’t have coherent ideas. On the contrary, their sound is expertly fashioned. It’s just that your head spins with what to make of it. The aggressive contrast between the wall-of-sound noise assault and the bright melodies that run through it, the way Alexis Krauss’s pop tart vocals are distorted, the teeny-bopper reference points, the sheer up-to-11 volume of it. It’s music designed not to be instantly boxed in with one word.