This Lyons-based quartet's latest album, which will be celebrated during a May 9 gig at the Boulder Theater (followed by appearances at the Gold Hill Inn and Swallow Hill on May 29 and June 6, respectively), stays true to bluegrass's traditions without coming across like a musty antique, due in part to the variety that spices the songs. Banjoist Chris Elliott, bass-fiddler Jessica Smith, guitarist Taylor Sims and mandolin player Alex Johnstone each take lead vocals on assorted tracks, and there are no weak links. Just as important, the tunes, produced in pristine fashion by Nashville sideman Jeff White, range from fast-fingered sprints ("In Despair") to dark, dramatic showcases ("Tangled in the Pines") and charming pace-changers ("Cuba Vera Swing"). Clearly, these four are on the Way Up.