Bristol’s Tectonic dubstep label brings fans a tale of two sounds on two discs. Compiled singles by staple artists like MRK1, Pinch, Loefah, Cyrus, and Omen are alternately sparse and restrained, manic and bombastic. Disc One of the set offers individual tracks, while the other is a seamless mix with only a few repeats. DQ1’s wobbly soundclash-inspired hit “Wear the Crown” and Digital Mystikz’s bleak “Molten” hold it down for the minimal steppers, while Omen’s “Full Metal Jacket” and Vex’d give you a dose of dutty subs. Everybody dance the Earthquake.