San Antonio is aggressively regional, which isn't to say you won't ever hear a top-40 song, or classic rock, or synthpop, or you-name-it. But the city thrives on Texas genres, on blues, conjunto, tejano, swamp, on root rock and country and folk music. North Saint Mary's is the biggest "strip" for live music and every club may well play something completely different from their neighbors.
More specifically, San Antonio has been called the "Nashville of Tejano music" and hosts the Tejano Music Awards.
No less live, but a little more formal, check out the German choral concerts in Beethoven Maennerchor Halle und Garten (where a good number of the members speak German as their native tongue). Or check out the San Antonio Symphony.
