The always-recommendable Ives Quartet is playing one of their recent commissions on this concert. David Conte is a fine local composer, who teaches at the Conservatory and has had a broad-based career, has an ear-pleasing idiom, and his String Quartet No. 2 should be a happy discovery for listeners who prefer the classics. The Ives has two of those sandwiching Conte’spiece: Tchaikovsky’s early string quartet (Op. 11), with the gorgeous andante movement thatis often excerpted, and Haydn’s “Frog Quartet (Op. 50/6, also in D Major), a masterpiece that extracts maximum variety from a limited set of themes.