Attempting a description of The Dirty Projectors started well enough but quickly became problematic. Leader David Longstreth dislikes easy comparisons to prog rock bands like Steely Dan, Yes and Frank Zappa but the music doesn't readily fall into any other category. The group has collaborated with an array of well-known producers and musicians, including David Byrne, Björk and T-Bone Burnett, among too many others to list. Presumably, if you are acquainted with their material, you'll find the show interesting. They have a new album, Swing Lo Magellan, to perform for you at Headliners Music Hall on August 14. POP ETC will open show. Tickets are $20.