Expect the unexpected at the Sebago-Long Lake Music Festival.

Now in its 39th year, the festival offers some of the most provocative programming on the Maine summer music scene. Tuesday night’s concert at Deertrees Theater in Harrison was no exception.

Where else could one hear Charles Dimmick, concertmaster of the Portland Symphony Orchestra, play second fiddle in a Beethoven quartet? Or find that quartet’s Op. 74 in E-flat Major (“Harp”) sandwiched between George Crumb’s masterful “Voice of the Whale” (1971) and Rebecca Clarke’s little-known and quite amazing Piano Trio? 

The program opened with “Voice of the Whale,” following the composer’s instructions for blue lighting and black masks on the musicians to reduce the human element. The instruments — flute, cello and piano — are electronically amplified and played in unusual ways. The flutist sings through the mouthpiece, the cello plays in a falsetto style, and the prepared piano has its strings strummed and plucked like a guitar.

While all of this may seem outlandish, the result is a magical depiction of an undersea world in which whales make music with “a system of proportions in the service of a spiritual influence,” to quote the composer.

“Voice of the Whale,” inspired by recordings of humpback whale songs, is one of those compositions that reveal new meanings with each repetition. The calm “Sea Nocturne” (for the end of time) which concludes the work now appears beautifully melodic, with its 10-note repeated theme that seems like a tone row but isn’t. 

The performers — Susan Rotholz, flute, Eliot Bailen, cello, and Stephen Manes, piano — gave an outstanding reading of a work that absolutely must be heard live for full effect.

Clarke’s Piano Trio, composed in 1921, was a revelation. Most relatively unknown composers, male or female, have been relegated to obscurity deservedly. Clarke is a notable exception. Her music, while tonal, is fiercely individual, complex but entirely legible, and satisfying in both musical and intellectual terms. And her ability to transform a simple motif made me think of the Beethoven quartet earlier in the program.

The trio reveals a style that is sui generis but bears comparison with Clarke’s contemporary, Shostakovich. For example, the final allegro vigoroso starts out as a highland dance and turns into a macabre and sardonic parody before resolving into a return of the first movement’s memorable themes.

Manes, on the piano, Movses Pogossian, violin, and Eliot Bailen, cello, gave it a fine, dramatic performance that revealed Clarke’s striking transformations.

Next Tuesday’s concert will feature a rarely heard Piano Quartet movement by Mahler, Debussy’s “Prelude to the Afternoon of a Fawn,” and an arrangement of Mahler’s Symphony No. 4 in G Major for chamber orchestra. For tickets, call 583-6747. 

Christopher Hyde’s Classical Beat column appears in the Maine Sunday Telegram. He can be reached at [email protected]