Schönberg or Schoenberg? In Los Angeles, where he landed after escaping the Nazis, the Vienna native dropped the umlaut. Either way, the name is synonymous with “atonality,” a term the composer disdained, and with 12-tone-music, which he may not in truth have been the very first to think about. Still, as prophet and practitioner of a revolutionary new language in classical music, A.S. was without question the man. His four highly dissimilar string quartets reflect his unpredictable evolution; the second, most unconventionally indeed, includes a part for a soprano vocalist. It’s almost routine to program the complete string quartets of Beethoven, Bartók, and other major avatars of the genre as “cycles.” To encounter Schoenberg’s en bloc is just about unheard of. —M.G.