Hailing from Amherst, Massachusetts, California X sounded like they'd been raised on a steady diet of old Dinosaur Jr. albums (with the odd Sonic Youth EP thrown in for texture) on their self-titled debut album, but the group's formula has grown a bit more ambitious on their sophomore effort, 2015's Nights in the Dark. The thick, rumbly guitar figures of frontman Lemmy Gurtowsky still take center stage here, but the addition of second guitarist Zack Brower brings a bit more heaviness to the group's attack, and there's a dour force to the melodies that suggests someone slipped some doom metal into this band's drinks. Nights in the Dark feels less song-oriented than the debut, with a pair of tunes splitting into two-part jams and the addition of a brief acoustic interlude, "Ayla's Song," that literally cuts off in mid-stream, but California X sure sound like a stronger, more confident, and better band their second time at bat. The shift from the slow, ominous build of "Blackrazor, Pt. 1" to the kicked-up heaviness of the song's second part is a great example of how California X has grown on Nights in the Dark -- this music hits hard but feels graceful and sure-footed at the same time, as Gurtowsky and Brower deliver solid riffage that blooms into solos that punctuate the melodies without overstaying their welcome, as bassist Dan Jones and drummer Cole Lanier give the performances both structure and velocity. California X have a way to go as songwriters, but Nights in the Dark shows they're maturing into a top-flight heavy indie band, and if you want to hear a group that know how to make their guitars signify, this may be just what you've been looking for.