Congress Street was empty of people, and the White Heart had but a half-dozen patrons at 8:30 on Sunday. Perhaps these few were pondering the same question: who is Esther, and what’s up with this mixtape business? Tonight would not yield any answers for them.

The band the 500s were the feature act for the evening, making their White Heart debut. The first distinguishing fact is that this trio has no bassist. There are guitar, keys, and drums with all members looking to share in the vocal duties. Their outfits with ties and sweater vests had me expecting something Weezeresque (Weezy?). By the beginning of their set, the attendance had swelled to over three-dozen people, with more on the way. The 500s played a half hour of spare, “economical” pop, with shortened song structures and most tunes not going over the three-minute mark. Their music leaned towards ’80s New Wave and Pop, somewhat like the Cure, but without those defining Cure elements of wet guitars and miserable vocals.