Max Tundra (aka British solo musician Ben Jacobs) was easily the most astounding live performer I saw in a long weekend of way too many shows at SXSW. Onstage, he sings like a pitch-perfect Auto Tune–free R&B crooner, fluidly improvises on keys and guitar, jumping from one keyboard to another to melodica to glockenspiel to thumb piano and back, and jerks and flings his body around spasmodically, always landing just on time over his own off-kilter backing beats, pausing to dole out droll banter between songs. With Junior Boys. (Neumos, 925 E Pike St, 709-9467. 8 pm, $15, all ages.)