The Norwegian Chamber Orchestra, making its Orchestra Hall debut this Sunday, has been a permanent ensemble since 1977, when Terje Tonnesen, first violinist with the Oslo Philharmonic, became its artistic director. It has performed around the world with soloists such as Mstislav Rostropovich, James Galway, and Joshua Bell, and its ongoing collaboration with pianist Leif Ove Andsnes has led to a 2000 Gramophone Award-winning CD of Haydn concerti and, in 2004, a CD of Mozart concerti--performances that display an exquisite balance between piano and orchestra and a striking chamber-music sensibility, with all the players listening carefully to each other and getting out of each other's way. Andsnes, with his impeccable phrasing and tone, blends his sound remarkably with the other instrumentalists, then dazzles in his solos. The orchestra members choose a period approach, using little or no vibrato, but their perfect pitch, warmth, and elegance make their sound accessible to more modern tastes. Andsnes will join them again for this concert, which opens with the sprightly but rarely played Haydn Concerto in G from the CD. In honor of Mozart's 250th birthday they'll play his darkest concerto, number 20 in D minor, along with his exuberant Eine Kleine Nachtmusik. Also on the program are Langsam und Schmachtend by young Norwegian composer Eivend Buene and Tonnesen's arrangement of Beethoven's last string quartet and last completed work, opus 135 in F. It's the shortest of the late quartets, with a stunning final movement. Text written under the notes of the opening motive asks "Must it be?"; the answer is in a joyful new section with text that reads "It must be!" The tension between the two is resolved with a surprising calm optimism. Sun 1/15, 3 PM, Orchestra Hall, Symphony Center, 220 S. Michigan, 312-294-3000 or 800-223-7114, $18-$43.