String quartets exclusively devoted to 20th-century music have become fashionable in recent years. With all the hype surrounding the Kronos Quartet, and all the underground respect for the Arditti, it’s more than a little surprising that the quartet to emerge as the unparalleled master of interpreting Bartok quartets should be the Emerson String Quartet, a group that often dips into the 18th and 19th centuries as well as the 20th. Their recently released set of the complete Bartok quartets is among the most revelatory interpretations of those masterpieces one could hope to encounter, and luckily Bartok forms the centerpiece of their appearance here this weekend as well. The virtuosic Bartok Fourth Quartet will be heard, along with a quartet by the father of the genre, the Haydn Quartet no. 3 in C Major, as well as the monumental Beethoven Quartet in C-sharp Minor. The Emerson’s ensembling, balancing, dynamic palette, and depth of feeling are second to none among currently active quartets. Tonight, 8 PM, Mandel Hall, University of Chicago, 5706 S. University; 702-8068.