On a most basic level, possession of a PA, or Public Address system, is what turns an ordinary room into a viable venue for live music. Barring the odd band that brings all their own amps and mixers—noise godheads Lightning Bolt, say, or local duo Haunted Horses—most bands will need to plug their microphones into a house sound system to be properly heard. Ironically, at least half the Cairo-raised bands playing this fundraising benefit to buy a new PA for the DIY arts space—post-punkers Stephanie and promising grunge-exhumers Naomi Punk, especially—deal in vocals blurred, smeared, mumbled, or otherwise sonically obscured. Who even knows what they’d sound like through a working PA? With The Millennials, Half Gift, The Numbs. ERIC GRANDY

Sat., May 19, 6 p.m., 2012