The American Composers Orchestra wound up its 40th anniversary season of presenting recent and brand-new works by Americans with an evening at Zankel Hall mostly by composers from, or better known in, the jazz world. As it turned out, the music itself was firmly in the contemporary classical camp except for some ragtime piano in Ethan Iverson’s exuberant if awkward Concerto to Scale, and a hint of jazzy winds in TJ Anderson’s Bahia, Bahia. Nevertheless, the program showcased diversity – of styles, race, gender, age – that is the hallmark of this organization.

Iverson is a pianist, composer and blogger best known as a founder of the Bad Plus, an experimental jazz group. He also wrote the score for the evening-length Pepperland, which the Mark Morris Dance Group presented last year. Concerto to Scale is the first work sponsored by the ACO’s Commission Club, a Kickstarter-like initiative aimed at having patrons invest in all costs of new pieces as they are developed. (Members own what amounts to “shares” in the work.)

The concerto is in three movements: Allegro, Andante and Rondo. Iverson was the soloist, sharing solo duties with a bass drum adjacent to the piano bench, whose player pounded out rhythms in sync with the piano while the orchestra launched into a medley of what sounded like 18th- to 20th-century classical melodies. The piece had verve, along with humorous moments, but the drumbeats became repetitious and ultimately came across as a gimmick.

Another jazz luminary, highly regarded saxophonist Steve Lehman, was more successful with his world première, Ten Threshold Studies. As sonically different from Iverson’s concerto as could be imagined, it explored, in the words of Lehman’s program notes, “elastic rhythms and shadowy spectral harmonies”. Percussion, piano and strings began with rhythmic thumps followed by myriad chords, harmonies and pizzicato by the strings swept into a satisfying whole. It should be exciting to hear what Lehman does in future outings.

The evening began with September Coming a brief, delicate work by 34-year-old Hitomi Oba. She, too, is a saxophonist, though there was no sax in her orchestra. Oba heads a 16-piece jazz orchestra and was a founder of the new-music LA Signal Lab. September Coming, the third world première, was developed through workshops and readings of the ACO Jazz Composers Orchestra Institute. Brass, winds and solo clarinet and flutes were sprinkled through this sprightly work.

Anderson, a 90-year-old composer and educator now based in Atlanta, was the outlier among the composers, both in age and style. (He was the only composer not present at the event.) Bahia, Bahia, written in 1990, was described as his “impression of popular music” heard during visits to Brazil. It revealed itself as a mash-up of post-modernist traditions and pop/jazz tunes, beginning with violins and violas softly tapping out pulses. A virtuostic turn by the single trombone, and an enthusiastic percussionist seated at a full jazz drum kit plus bongos, punctuated the latter part.

The evening concluded with a 2009 composition by Clarice Assad, Brazilian-American singer, pianist, composer and bandleader. Her celebrated musical family includes her father Sergio and uncle Odair, who comprise classical guitar’s Duo Assad. Dreamscapes, her concerto for violin and orchestra, lent its name to the overall program and was based on her investigations of REM sleep and dreaming. Elena Urioste was the assured soloist. Its introduction offered a lush vocabulary of Neo-Romantic sounds, followed by a soulful interplay between violin and cello. After a transition to an agitated violin solo, the finale returned to a measured reprise of the violin-cello duet with strings. Having heard Clarice Assad in person only as an engaging jazz singer and pianist, I was thoroughly impressed by this example of her classical chops. 

Veteran conductor George Manahan, who is the music director of the ACO, handled the program with his customary aplomb.