There are many other ways to make a guitar sing besides plucking and strumming, and Roth has access to more of them than most guitarists: scraping, sliding, tapping, wiggling, in all manner of combinations. He uses these techniques for structural delineation and painterly suggestion; a switch from one to another might come at roughly the same juncture where another player would kick on the reverb or distortion. There’s a moment toward the end of “Waiting” when grayscale staccato tones suddenly give way to funhouse-mirror visions of wobbly, borderless color—a passage that would be impressive in a free-improv set and is positively joyous in the context of a song about frustrated stasis.…