The two gals and two guys in the Whispertown 2000 are too cutesy to be considered freak-folk and too roughshod for indie-pop. Instead, the band settles for a sound somewhere between the two, with the close harmonies of Morgan Nagler and Vanesa Corbala acting like siren songs to weary listeners. In concert, the quartet's arrangements are ragged and simple, thanks to loose drumming, root-note bass-playing and the folksy strums of Nagler's acoustic guitar. But on last year's Swim (released on Acony Records, the label run by David Rawlings and Gillian Welch), the band takes advantage of studio trickery to flesh out its sound. "Erase the Lines" moves from a minor-key dirge to a reverb-filled tempest, and an out-of-tune piano gives some barroom ambience to the coda of "Pushing Oars." Fellow ragged-folk practitioner Theodore will open the show.