Martin's latest Bug album, London Zoo, is very much in keeping with that permutation, which stands out amidst the recent wave of dubstep in a way that makes Burial's Untrue sound like Music for Airports. But it also takes the Bug's work into a somewhat cleaner, less abrasive area-- it streamlines the sound, shaves away the distortion, and draws most of its impact from the rhythms themselves. Of course, "less abrasive" doesn't necessarily mean it hit any less hard: Martin knows how and when to drop a heavy beat directly on top of you, and there's a carefully crafted tension throughout this record, no matter how sparse or dense that beat actually is. Sparseness and density tend to work in tandem on London Zoo's strongest tracks: Bass hits at machine-gun intervals, leaving deep, tube-station echoes disintegrating in its wake and giving a number of these tracks a simultaneous sensation of freeness and claustrophobia. Reverberating, distorted voices and spare synth melodies close in on you even as they recede into the distance, and the rhythms are so pervasive and locked in that after a while you start hearing the spaces in between as much as you're hearing the beats themselves. Singer/toaster Ricky Ranking shows up on three tracks as well, and his vocal range-- switching from sweet melodies to foreboding chants-- is impressive, even if he's best suited to the slower numbers (especially the dirgelike closer "Judgement"). And the two appearances from Warrior Queen are knockouts: "Poison Dart", originally released as a single last year, is ruffneck feminism ("Though me na sling no gun, a boy think sey me soft/ But me a real poison dart") delivered with a sharp, wailing sneer over more low end than most MCs could contend with, and "Insane", which augments a chirpier, more buoyant flow with a smoothly-sung chorus and a few out-there adlibs, including a funny little riff on Tears for Fears' "Mad World". The only caveat concerning London Zoo is how far it might skew away from your traditional notions of dancehall-- and even then, it helps to recognize that, if anything, this record is another manifestation of how London has transformed the sounds of Jamaica to its own ends, from 2-tone to jungle to dubstep. It's a tense record, sure, but that tension is palpable in a crossover-friendly way, invoking Babylon and fire while avoiding the more problematic aspects of "slack" lyrics. It's angry and ferocious, but always triumphant: When it threatens to bust out your windows and rip holes in your speakers, it crackles with the kind of force that makes you want to punch the air as hard as your subwoofers do.