Disco citizen San Serac (of Output Recordings) and Junior Boys refugee Johnny Dark collaborate on this short and sassy (23-minute) take-down of apathy (“Your Collapsed State”) and, kinda, their audience (“Pack Moves”). It’s an unusual quasi-failure, because Dark’s exhilarating, hip-hop-meets-two-step production is there; Serac’s throaty, sexy delivery is there; and the lyrics can be insightful and uncharacteristically poetic for ’80s-inspired electro. But all too frequently, the harmonies and notes seem strikingly off. This duo has the potential to knock Hercules off the vocal-disco throne, or at least incite the same fervor among the glitterati, but it’s not happening this time.