St. Matthew’s Lutheran was not much over half full for Monday’s Intermezzo program. A shame, because two very rare and unusual works (attractive ones, too) of smaller scale were delivered; each calling for fewer than a dozen players.

The first was by a composer who’s only recently begun to get the attention he deserves: the Salzburg master Heinrich Biber. He was kind of the Charles Ives of the early Baroque, experimenting audaciously with strange violin tuning schemes, dissonance and many other offbeat musical forms and techniques.

His La Battalia is an almost never-heard work for ten assorted strings players plus harpsichord that demonstrates one of the era’s cultural fads: the celebration of war in poetry and music. Its six movements cover such programmatic themes as a soldier’s sad farewell to his family, troops marching to the fife and drum, the drunken revelry of soldiers, the battle itself, and the lament of the wounded. Sound effects abound – including the noises of gunfire. The dissonance? Just imagine how eight different drinking songs sound when played simultaneously and in different keys.

The final work is another rarity: Concert (the French term for concerto) – for solo violin, piano and string quartet – by the late-romantic French composer Ernest Chausson, who’s remembered today for only a handful of carefully crafted works. And it tends to take the listener by surprise, with its gorgeous, rolling opening section, with the solo violin soaring over cascades of pearly piano notes. And the rest of it’s just as striking.

Sadly, Chausson never really believed in himself as a composer – and he died young, before achieving either fame or his full potential. As quoted in the festival brochure, He once expressed his wish to “have written something, be it no more than a single page, that goes to the heart.” If only he could’ve heard the loving treatment that these wonderful SFO musicians gave his handiwork — not to mention the applause (and the standing O) that it inspired here.