AU has never been an easy band to pin down. Since its inception in 2005, the Portland trio has bobbed and weaved its way around classifications and genres, melding triumphant symphonies and drone-y soundscapes with jazzy drums, dizzying guitars, and lyrics that fluctuate between the sedated and the emphatic. On Both Lights, the band delivers a dense collection of tracks that seems at first too fussy to unpack. Opener “Epic” is a word-less, violin-and-drum frenzy that seems to start at the top of a mountain and build up, while closer “Don’t Lie Down” explodes slowly from a cavernous vocal track to a wall of distorted sound. Though the band has often been lumped in with modern-day experimenters like Animal Collective and Grizzly Bear, Both Lights seems to borrow equally from late ’90s auteurs like Maserati and Godspeed You! Black Emperor. In other words, it’s post-rock for the new generation, and given time, it unveils a sonic world far richer than most ever imagine. AU plays Muddy Waters Café on Wednesday, October 31, at 8 p.m. Visit clubmercy.com for info.