Like Ricardo Villalobos and Omar S. before him, Sam Shackleton has packed his entry in the famed Fabric DJ-mix series with his own music. Cheeky, but we're not complaining, as it's possibly Fabric's pinnacle so far. The English producer has been injecting dubstep with siroccos of broodingly dark atmospheres; jittery, skittering hand percussion; ocean-floor bass pressure; and chilling vocal samples since 2005, when he co-ran the defunct Skull Disco label. With this new mix, over which he scatters 22 tracks, Shackleton reconfigures old material and threads in new cuts to form a gripping, cohesive mission statement: to turn your fancy club into a haunted house with a kind of urgent, tribal/ritual rhythmagic that seems at once ancient and utterly 21st century. It's not so much dance music as it is a macabre panic-at-the-disco soundtrack. Fabric 55 makes a new, improved sort of adrenaline squirt through your synapses.