The Infamous Stringdusters, those noted purveyors of groove-friendly bluegrass, formed in Nashville in 2006. According to PopMatters, they “take traditional bluegrass and old-timey music and use it as a launching pad to explore other, more improvisational, free-flowing forms.” And while the band’s lineup hasn’t been exactlky free flowing, there have been a few personnel changes over the ensuing years: Guitarist Andy Falco joined when Chris Eldridge departed to join Punch Brothers, and several years later, the man on the mandolin, Jesse Cobb, left the band. But Travis Book (upright bass), Jeremy Garrett (Fiddle), Andy Hall (dobro) and Chris Pandolfi (banjo) have all been around since the start. And together, they’ve put out five albums (one of them a live LP), the last of which, Silver Sky (stream it below), came out in 2012. But their newest full-length, the highly anticipated Let It Go, arrives next Tuesday. And the Infamous Stringdusters (above, performing “Let It Go” and, below, covering Lorde’s “Royals”) are already out on the road in support of it. Their tour brings them to New York City to play The Bowery Ballroom on Thursday night.