"I feel very much like an orangutan," quipped pianist Gilbert Kalish, hunching his shoulders and spreading his arms wide, aping the physical demands required to perform composer George Crumb's music.

The post-concert remark was well taken at the Kennedy Center Terrace Theater Wednesday night, for he had spent the better part of an hour variously plucking and thwacking the concert grand, with one hand on the keyboard, the other inside the piano.

There certainly was nothing ham-fisted about his playing, for his remarkable dexterity was an extension of his effortless virtuosic touch. Mezzo-soprano Jan De Gaetani and violinist Paul Zukofsky likewise met the severe technical challenges posed by Crumb, who was present and appeared pleased by what he heard.

Kalish and De Gaetani opened with the world premiere of "Three Unpublished Songs," reminiscences nearly 40 years old. Crumb's later apology for "inflicting his juvenalia" on the audience notwithstanding, these songs contain a Gallic clarity of vocal line and quicksilver accompaniment that suggests Debussy. Following with "The Sleeper," set to a poem by Edgar Allan Poe, the duo fast-forwarded to 1984, creating a haunting atmosphere filled with harmonics, glissandos and muted tones by the piano, humming and sprechstimme effects by De Gaetani.

Zukofsky and Kalish retained this mood in "Four Nocturnes" (Night Music II), an array of fluttering sounds and indeterminate bumps in the night, before Kalish took the stage alone for "Gnomic Variations." With the piano lid removed, he coaxed thunderous volleys and oblique, darting melodic strands from within and without. It was truly a performance to see as well as hear.

De Gaetani joined him for a stirring rendition of "Apparition," which combined verses by Whitman with musical references by Crumb to represent the cyclical nature of life and death. Her vocalise episodes imitated bird calls and conjured evil spirits with discordant phrases, as if she were "singing in tongues." The circular concept reassuringly prevailed, though, as De Gaetani ended as she had begun with a luminous melody support by Kalish strumming the strings like a zither.