It's no surprise that the city of Bristol should be a hotbed of activity surrounding the U.K.'s most recent electronic music subgenre, the bass-heavy dubstep. After all, Bristol was also Ground Zero for trip-hop in the '90s, home to Massive Attack, Tricky, and Portishead. This two-CD set compiles many, if not most, of the notable tracks of the past few years, the majority of which combine pumping rhythms (slower than drum'n'bass, faster than hip-hop) with oozing low-end synths and minimal, if any, vocals. A lot of dubstep tries too hard to be scary, with sampled dialogue from horror movies and synths that aspire to be John Carpenter movie soundtracks, but most of what's included here is by artists including Pinch, Appleblim, and Peverelist, as well as Smith & Mighty, whose dancehall-derived work from an earlier generation greatly informs much of what's heard today. The latter's contribution, "B Line B Flo," is much more of a dancehall/drum'n'bass workout than the humming, throbbing instrumentals that make up the bulk of this set. But it provides a sense that the Bristol scene is aware of its history, something that can't always be said of electronic music communities.