Dub is easily identified but difficult to define. Is it a style, a genre, or an approach to sound?
Mad scientist Lee "Scratch" Perry practically invented it in his Jamaican laboratory, yet reggae inflections are often absent from the work of modern purveyors. A quick glance at those who claim (or are claimed) to be influenced by dub only heightens the confusion: Massive Attack's atmospherics are often attributed to it; Audio Active's techno frenzy in part derives from it; even Tortoise's studied use of silence has been dubbed dub.
Tokyo's Dub Squad is straightfoward about their debt to dub. The group began in the early '90s as a reggae unit, but the usual, technical definition of dub -- with guitars cutting in and out and a one-drop beat manipulated with echo effects -- is found sparingly, if at all, in most of their work.