Sometimes opposites really do attract. Sonar is an eight-year-old Swiss “post-minimalist” quartet that combines austere, oddly interlocking rhythms with a distinctive tritone bass and guitar tuning, and does so with mathematical precision (their primary songwriter, Stephan Thelen, actually is a mathematician). They proudly proclaimed their first couple of records “live in studio,” without any loops or post-production gadgetry. Guitarist and producer David Torn is an inveterate tinkerer, looper, pedal-stomping electronics wiz, and maestro of the volcanic splatter. His kindred spirit in avant-garde guitar, Henry Kaiser, thought Torn producing Sonar would be a magical matchup. The chemistry was immediately evident, to the extent that Torn essentially became a fifth band member.
On Vortex, the template that’s made Sonar an art-rock cult favorite remains intact. There’s enough space in Thelen’s songs for Torn to overlay his own sensibility. Sonar is life at ground level; Torn is the weather. Their interaction feels at once organic and bifurcated. The aptly named title track could be a 10-minute sonic simulation of a tornado moving through a town. Its spare intro groove is quickly shrouded by an ominous ambience. The rhythm section perks up, gusts of intensity wax and wane, presaging the larger siren wails and pummeling that inevitably arrive. By contrast, “Waves and Particles” finds Torn adding a sunset-like brilliance to the already translucent beauty of Sonar’s tuneful math.