A veteran band’s later work may unravel, like Talking Heads’, or sink into cluelessness, like Blondie’s. But when, as with 2005’s Rolling Stones, old bands refine the tack at which they have excelled, later work can achieve an exhilarating authority, a resonant completeness. That’s what the American Analog Set’s Set Free does: The Austin-based band’s sixth collection is like a painter long engrossed with azure who now bursts forth with the sky itself. Soft jaunts such as “Born on the Cusp” and droney plaints such as “She’s Half” breathe melodies so deftly, insinuatingly droll that TAAS could have reimagined them from ancient Shoes records; and the tunes are draped in the band’s preferred instrumentation of sandy rock midtones and old-denim drums, plus nothing else. “Cool Kids Keep,” an extraordinary mystery groove, posits the outdated ’90s idea of Pavement fans being somehow superior to Candlebox fans with such focus and killer romanticism that, in the end, the piece comes to be about the desperation and the immortality of cliques. That’s no everyday feat, opening up the whole problematic notion of the cool to both criticism and apotheosis. But twists like that are the kind of thing TAAS expose effortlessly with their whispers, their brushes, their soft fuzzy guitar notes.