Complain that SBTRKT's sophomore effort wanders too much -- in search of what it means to be "post-dubstep" -- and it's an argument worth putting up for debate. The London producer's second album jumps genres with abandon and nothing sorts itself sensibly until after a couple listens, plus the one- or two-note interludes feel like disingenuous bridges throw up at the last minute. The album sorts itself after a handful of listens, or just a couple for those who adore the producer's musical palette (think of the dark space between the underground Burial and the more aboveground Trentemøller), but the big win for SBTRKT is that these songs are worth latching onto, including the title track where R&B vocalist Sampha declares "impermanence is so permanently with me," thus stating the album's flights-of-fancy theme. With "Problem (Solved)," that fancy is creating an R&B, pop-and-lock ballad with the murky Hyperdub set in mind, while "Voices in My Head" with A$AP Ferg is cloud rap-jazz with all the off-kilter beats and smoked-out lyrics that infers. When Vampire Weekend's Ezra Koenig joins for "New Dorp. New York.," indie dance is brought into the mist as if LCD Soundsystem did downers exclusively, and while the track is a new kind of swagger that satisfies, it's another dark dip into the album's endless cavern of maudlin. Good chance newcomers will fall for the singles and be frustrated by the perceived filler, but that's the biggest fault with Wonder Where; it could be more persuasive and open. On the other hand, predisposed listeners will actually be primed for such a slow and sad journey, and will welcome such a "follow the music" attitude, even when the lyrics and moods always seem to land on "pensive."