How long can a wave be a wave before it’s considered a flood? Because chillwave — that syrupy sweet lo-fi indie-pop sound that was supposedly a trademark of two summers ago via one-man outfits like Washed Out, Toro y Moi, and Neon Indian — just seems to keep on cresting. But what’s that old saying . . . nothing AM-Gold can stay? The debut full-length from Brooklyn’s Small Black, “New Chain,’’ is a 10-song chillwave workout, and it might mark the microgenre’s peak. Let that not suggest excessive energy; these songs all sound barely out of bed — and make a fitting suite to accompany a creeping winter. “Crisp 100s’’ is a drowsy gem, coasting along on grainy melodies and through clouds of fuzzy reverb, with Josh Kolenik’s low-key croon losing itself in echo. “Goons’’ tempers its crush on My Bloody Valentine into scratchy bedroom pop. Standout jam “Photojournalist’’ spreads itself out upon howling synths, washes of noise, and thumping drum machines. It’s catchy, sweet, and maybe a little messy, and maybe a bit too long. Still, Small Black proves it isn’t merely the finest exemplar of a fleeting trend, but the best possible crew to be on top when the wave (finally) breaks. (Out tomorrow) MICHAEL BRODEUR
Small Black plays Great Scott Nov. 21.