Bands excel in many different ways. If you're a punk band, you could do worse than always sounding like a train speeding wildly down the tracks, with the potential for derailment around every sharp turn. On last year's self-titled debut, released by the great Trouble in Mind record label, Negative Scanner has that quality locked down. The Chicago band leans toward the post-punk side of punk, pitting Rebecca Valeriano-Flores' snarled bark against savage bass lines and sharply barbed guitars in a package that's taut and concise, but with a proud ragged edge. Tonight, Negative Scanner's DIY tour brings them to the Know, where they'll share a shadowy bill with like-minded local punk bands Arctic Flowers, Dark/Light, and Dr. Identity. BEN SALMON