The best thing about Brighton’s Diagonal is that they’ve made an arty prog record that focuses on clean sounds and energetic playing with a melodic sense of purpose. There is absolutely no trace of metal’s doom-for-doom’s-sake darkness, or space rock’s druggy, spiralling noise to conceal a lack of songs, or psych’s directionless jamming that betrays when a band would rather play live than record in a studio. (Well, except for the album closer “Capsizing,” which veers closest to the kind of soundtrack work that ‘70s prog gods were relegated to doing in the ‘80s once seriousness and long hair fell out of vogue.)

Yes, there’s a lot of technical showboating on The Second Mechanism, but Diagonal aren’t entirely over the top; they temper their hyperactivity with welcome restraint. “Voyage/Paralysis” backs one solo with a rhythm section clearly directed to let loose into an exotic dance section complete with saxophone. But otherwise the track defines itself with upbeat, upfront drumming and guitars that play angular, repeated melodic motifs that stand out immediately upon first listen. Other bands would bury these elements in noodling.

“These Yellow Sands” is dreamier and more languid, with the sax now playing the part of the lead guitar. Tinkling piano and the hint of an angelic chorus both add gentleness and texture in the deeper, quieter passages, showing effectively how the band is not afraid to work outside of a rock context; the Arabian nods in the sound are more Pure Moods than “Kashmir.” But eventually the energetic beat and melodic guitar take center stage again, and the track mixes up a frenzy of horny, world-beat energy.

It’s only “Mitochondria” that suggests that, with its repetition of already-familiar elements,The Second Mechanism is short of ideas. Again, the sax plays the lead solo role while the guitar focuses on rhythm. That each track eventually turns into something akin to jazzy klezmer is a gimmick overused.

Diagonal never lose crucial momentum or play listlessly, and The Second Mechanism is mostly a bright, engaging listen that grows predictable but never bores. Occasionally the band auditions new elements, such as the unnecessary but not unwelcome vocal contribution to “Hulks,” the album’s most straight up post-Sabbath rock song. But even that track devolves into more of the same for several minutes before recovering nicely at the end.

Perhaps the band, regrouping after a radical lineup change, felt a need to prove itself by reestablishing a core sound, which it does. But in doing so, it leaves its heart—oops, I mean its glowing dodecahedron on a bed of neurons—on its sleeve for a little too long, when most musos instead tend to be overstuffed with surprising ideas