Cello is the new guitar. And by 2025, NUVO predicts that the chamber-skiffle movement will take root around the world, with cellos replacing acoustic guitars in nine out of ten dorm rooms. The electric cello will also become commonplace after Yo-Yo Ma moves into his late-career acid-jazz freakout stage. Let it now be noted that the Cambridge-based Lindsay Mac forged the way, demonstrating that cello can be a viable instrument for a solo singer-songwriter, even one who wants to stand up on stage. About seven years ago, Mac ditched her bow and strapped the cello to her body, wrapping a guitar strap around the fingerboard. Without the bow, she employs techniques both familiar in the classical world (plucking the strings) and a little more esoteric (hitting the body of the cello for percussion, strumming). Her lyrics, which are in a more traditional, first-person introspective mode, take on an added resonance against the fuller, mellower, more mysterious sound of her cello. Locals Kendall Ludwig and Tiff open for Mac Tuesday, Oct. 27 at Radio Radio, 1119 E. Prospect St. Doors open at 8 p.m. for the $5 show.