The music Endangered Blood plays is melodic and exclusively—almost emphatically—acoustic. But that’s easy to forget when the avant-garde ensemble knocks you out of your chair with the force of raw, over-amped rock ‘n’ roll. Not everything it plays is so molar-rattling, of course; the quartet led by tenor saxophonist Chris Speed and drummer Jim Black (which also features bassist Trevor Dunn and alto saxophonist/bass clarinetist Oscar Noriega) can do meditative, too, even if Black’s manic, freeform rhythms still ward off outright calm. Running through these contrasting moods, however, is the same pugilistic attitude that you find in punk: an unspoken but unmistakable resolve that just because this music is complex doesn’t mean it won’t smack you in the gut. Wear a chest protector. Endangered Blood performs with Noveller and the DC Improvisers Collective at 8 p.m. at Atlas Performing Arts Center, 1333 H St. NE. $25. (202)399-7993. www.atlasarts.org.