The Chicago Ensemble is blessed with a camaraderie-enhanced excellence but cursed with a persistent inability to connect with a younger audience. To be sure, in its 19 years of existence it has carved a comfortable though tiny niche, surviving as a reliable purveyor of eclectic chamber classics and an ardent presenter of relatively new works. But its loyal subscribers have aged, and the ensemble–whose core membership is now down to founder Gerald Rizzer (piano), Susan Levitin (flute), Sherban Lupu (violin), and Julie Zumsteg (cello)–seems at a loss at attracting the under-40 crowd. The predicament also plagues other chamber performers, of course, but the ensemble’s stuffy, professorial deportment does little to counter the impression of music dispatched from a high pedestal. This isn’t necessary, especially given Rizzer’s penchant for non-Eurocentric variety. The group’s season closer is a telling example. Alongside Bach’s Trio Sonata in G, Schumann’s Trio no. 2, and Schubert’s Sonatina in A Minor are the playful Assabioa Jato (“Jet Whistle”) by the Brazilian iconoclast Heitor Villa-Lobos and Child Song by the Cambodian-born Chinary Ung. Ung’s piece, in fact, was commissioned by Rizzer for the ensemble a decade ago. Since then the underheralded Ung, who’s taught in east-coast colleges, won the coveted Grawemeyer Award. The first and only time I heard Child Song I was struck by the skillful, unobtrusive way strands of Cambodian folk melodies were woven into a sparse Carterian texture. And the ensemble’s performance was on the mark in suggesting the piquancy and exoticness of the music’s southeastern Asian roots. A second hearing is overdue. Sunday, 3 PM, International House, University of Chicago, 1414 E. 59th; 907-2190. TED SHEN