Rinde Eckert calls his career a "wonderful mistake." He started as a trained opera singer but found that discipline too confining for his free-roaming creativity. So he drifted into experimental theater in the San Francisco area. Over the years he has been an actor, librettist, director, avant-garde playwright and composer.

Among Mr. Eckert's admirers is the composer John Adams, who chose him to open the weekend festival called "In Your Ear Too" that he organized at Zankel Hall. On Friday night Mr. Eckert presented his two-part work "An Idiot Divine," an iconoclastic, category-smashing and often riveting piece of ‹ well, I guess you'd have to call it performance art.

Part 1, "Dry Land Divine," loosely tells the tale of an evangelical minister in Wyoming in the 1950's who spends 14 years in prison for manslaughter.
With his lanky frame clad in gray prison garb, Mr. Eckert became that prisoner, who passes time with an accordion and seems obsessed with water dousing. At first Mr. Eckert played soft, rippling repeated figures on the accordion over which he sang a textless, eerie chant. The music segued into a folkish waltz, which slowly disintegrated, sending Mr. Eckert's prisoner into an outburst of animalistic panting at once ferocious and hilarious.

At one point his plaintive chanting, through electronic processing, was turned into something quasi-medieval, with multiple voices singing in astringent parallel lines. Mr. Eckert's music here was mostly intended, it seemed, to create effects and tap primal feelings. Yet there were wonderfully strange sounds to enjoy, as when Mr. Eckert banged clanky rhythmic patterns with metal sticks on a bucket, alternated with gentle whooshes of stirred-up water.

In Part 2, the more abstract "Idiot Variations," Mr. Eckert plays the village idiot who imagines himself a mystic, dressed in the ragged white robes of an Indian sage with a string of Tibetan bells hanging from his neck. It would have been easy here to slip into the cliché of the mentally unhinged outcast who spouts spiritual wisdom. But despite the length of the piece (45 minutes), Mr. Eckert's wild imagination mostly kept you entertained, amazed and, quite often, moved.

One moment he would sing a weird amalgam of opera, be-bop, click-clacks and nonsense. In the next he would hold a wordless argument with himself by speaking through the mouthpiece of a baritone horn to produce two distinctive and all too recognizably human voices: one high-pitched and whiny, the other huffy and officious. Though there were clever verbal riffs in "The Idiot Variations," as when the character gave explanations of the specific function of each finger on the human hand, most of the work conveys the idiot's poignant attempts to communicate through only sounds and singing.

To appreciate Mr. Eckert's piece, you have to adjust to his surreal sensibility. An enthusiastic audience did just that. Thank goodness Rinde Eckert abandoned an opera career.