Bates makes extensive use of the synthesizers and other computer-generated effects for which he is known. But much of the score is richly melodic and relies on more-or-less traditional orchestration to accompany the singers.

"I've found in my symphonic music that electronics are a little bit like a pet snake," Bates said. "Treat them very carefully. Twenty-five percent of the power of electronics is the silence when you're not playing them. Because then when they come in, they're a new element."Each character has a unique sound world. As Bates described it, there are "quicksilver electronics and acoustic guitar picking" for Jobs and "oceanic strings and grounded harmonies" for his wife, Laurene. Kobun, Jobs' Buddhist spiritual adviser, has "prayer bowls, gongs and chimes"; Steve Wozniak, Apple's co-founder, has "saxophones that associate him with a jazzy world"; and Jobs' girlfriend, Chrisann Brennan, is "our hummingbird with this glittering upper register.""When people start interacting, those sound worlds collide and wash into each other," Bates said, "and that's when things get interesting."Bates said he knew immediately he wanted Jobs to be a baritone, "a kind of Billy Budd with a little more edge." Edward Parks sings the role in Santa Fe, with mezzo Sasha Cooke as Laurene, tenor Garrett Sorenson as Wozniak, bass Wei Wu as Kobun and soprano Jessica Jones as Chrisann. Michael Christie will conduct.

"Jobs" is the 15th world premiere for Santa Fe and expectations are high. Further performances are already planned in the high-tech communities of Seattle and San Francisco, as well as at Indiana University, and a commercial recording will be released by the Dutch label Pentatone.

Matthew Shilvock, San Francisco Opera's general director, first heard the score at a workshop sponsored by Cal Performances and said he was "completely blown away by its musicality and humanity."Perhaps nowhere are these qualities more evident than in the emotional climax of the opera. It's 2007 again, and with Jobs still in denial about his pancreatic cancer, Laurene sings an aria that begins, "Humans are messy, awkward and cluttered." She's pleading with him to accept that he can't control the world the way he does his machines — and also delivering an ultimatum that he seek help if their marriage is to survive. At the end, he agrees.

"He was searching for inner peace, but it took him a lifetime to get to that place," Bates said. "And I think his recognition of his mortality helped him get there."

AP