Founded in 1975 when its members were students in Budapest, the Takacs remains one of the world's best string quartets. Their 1998 recording of Bartok's six quartets received a Gramophone Award and is still the gold standard for these works, and their 2005 set of Beethoven's late quartets just won a Grammy, as did their 2002 set of his middle quartets. Their last Chicago appearance, at Orchestra Hall in March 2004, was an all-Beethoven concert, and their performance of the op. 135 quartet left the audience barely breathing. Gutsy and passionate, they immerse themselves totally in the music, and their interpretations are profoundly musical, deeply emotive, and completely convincing. Of the original members, only second violinist Karoly Schranz and cellist Andras Fejer remain; first violinist Edward Dusinberre joined in 1983, violist Geraldine Walther--the first woman in the quartet--last summer. Adjusting to a new member is "difficult, but it makes you grow and stretch to allow for a new point of view," says Dusinberre. "We loved her warm tone and her solo playing--and we're having a great time." For this concert they've put together a wonderful mix of masterpieces. In honor of Mozart's 250th birthday they--and former Cleveland Quartet violist James Dunham--will play one of his late string quintets, the K. 515 in C major. "On the surface it's sunny," says Dusinberre, "but unlike Haydn, there's always so much more lurking beneath the surface." They'll also perform Schubert's melancholy Rosamunde Quartet in A Minor and Bartok's Quartet no. 2, with its two lyrical, contrapuntal slow movements bookending a rhythmically propelled second movement inspired by a trip to North Africa. Fri 2/17, 8 PM, Mandel Hall, University of Chicago, 1131 E. 57th, 773-702-8068. $30, $11 for students.