The MET Orchestra Chamber Ensemble takes extraordinary musicians from the orchestra of the Metropolitan Opera and allows them to ply their craft in more intimate and stylistically flexible configurations. In the fifth of six concerts this season, the ensemble performs an impassioned early work by Schoenberg, Mozart’s beloved Clarinet Quintet, and Respighi’s setting of Percy Bysshe Shelley’s Il tramonto, the latter featuring Metropolitan Opera mezzo-soprano Tamara Mumford.