21st Century Consort (Aaron Clamage/Handout)

Pianist Lisa Emenheiser earned every decibel of the ovation that erupted as she ended her marathon one-hour performance of Frederic Rzewski’s variations on the Chilean protest song “The People United Will Never Be Defeated!” that made up the first half of the 21st Century Consort’s program at the Smithsonian’s McEvoy Auditorium on Saturday. It was an hour of the most intense music-making and pianism — six sets of six variations each, organized like a fractal, a geometric structure in which each part of the whole mirrors, in miniature, the whole. In this case the variations within each set focus, in turn, on the qualities of simplicity, rhythm, melody, counterpoint, harmony and, finally, a combination of these, and each of the six-variation sets is colored, in turn, by these same six qualities. Would this structure reveal itself to the unsuspecting listener if it weren’t so well described in the program notes? Probably not, but as an organizing principle it gave coherence to a complicated hour of music.

With only a single brief break after the 18th variation, Emenheiser found an astonishing array of touches, balances and timbres. Gentle glissandi gave way to icepick-sharp single notes scattered all over the keyboard. Moments that sounded like Ravel had just stopped by to say “bonjour” shared a brief fling with passages that were mostly silence. Variations morphed into one another without a break; emotions flashed by; timelessness followed hectic anxiety, and Emenheiser navigated through it all coolly as if it were no big thing. It was a big thing, and she did it magnificently.

The second half of the program featured the premiere of “Two Yeats Songs” by Consort favorite David Froom, performed here by soprano Emily Noel and violinist Elizabeth Adkins. Froom writes well for the voice, and these songs have the violin and soprano engage in companionable dialogue. Adkins handled her lines with her accustomed elegance. Noel, who seemed at ease in the music, didn’t always find the center of her pitches and, like so many singers, seemed far more enamored of the vowels than of the consonants in the wonderful texts.

Cellist Rachel Young gave an uneven reading of Osvaldo Golijov’s “Omaramor” but redeemed herself in collaboration with Adkins and pianist Lura Johnson with a rollicking account of Paul Schoenfield’s “Sha’atnez,” a set of variations on “Dark Eyes” that roams around from unbridled tango to baroquely correct fugue.

Reinthaler is a freelance writer.