Powerhouse Sound, one of reedist Ken Vandermark’s best bands, plays a free gig tonight at the Empty Bottle to celebrate the “Jazz Issue” of Stop Smiling magazine. The quartet, rounded out by drummer John Herndon and guitarist Jeff Parker of Tortoise and bassist Nate McBride, explores the meeting point of funk, rock, free jazz, and noise. Doors open at 9 PM and the show starts at 10:30 PM.