Guitarist Ian Williams and drummer John Stanier both trained in a specific subset of Eighties and Nineties indie music, usually called math rock. This isn’t that helpful. Don Caballero (the band Williams was in) was built around the minibar-falling-down-stairs thunder of drummer Damon Che, and Stanier was the hydraulic press at the center of Helmet. These are rhythm bands, and sometimes they subdivide beats and build songs from tricky time signatures, sure, but it’s not an academic kind of music. In the early aughts, Williams and Stanier found each other and formed Battles, which has added and subtracted members over the last twenty years. Gloss Drop is one of the albums done as a trio with bassist Dave Konopka. Almost every Battles song is a series of rhythmic patterns expressed on different instruments and cycled through, together, as a tandem task. Battles go in and out of being instrumental; in their quartet formation, with Tyondai Braxton, there were vocals as often as not. On Gloss Drop, there are only four guest singers, but Matias Aguayo gave the band the closest thing they had to a hit, the delirious “Ice Cream.” (It also has one of the best videos of the aughts and the Barcelona firm behind the video, Canadá, went on to work with Rosalía). Gloss Drop is immensely fun, a bit like a bass tank designed by Jean Dubuffet, spewing sparks and blasting circus music around the bottom of a quarry.