By NATE CHINEN

Pat Metheny, the jazz guitarist, has lately spent an inordinate amount of time thinking about robots. “I haven’t slept more than four hours a night for six months now,” he said one day last fall at a rehearsal space in the Greenpoint section of Brooklyn .

Wearing a T-shirt and faded jeans, his tousled mane tucked under a baseball cap, Mr. Metheny stood before a 4-meter-high, 10-meter-wide wall festooned with musical instruments: an imposing, circuit-wired one-man band. The contraption sprang to life in a mechanical whirl: beaters tapping cymbals, levers gliding over strings, mallets cascading across a vibraphone.

Mr. Metheny closed his eyes and hunched over his guitar, bringing a human touch to “Expansion,” the centerpiece of his new album, “Orchestrion” (Nonesuch). The tune combined aspects of post- Coltrane jazz and Brazilian pop with cinematic breadth. So beyond the obvious technical feat - thousands of moving parts, executing a programmed score - the performance dazzled on a basic level. Mr. Metheny and the unmanned orchestra were making his kind of music.

“This is something I’ve literally been dreaming about since I was 9,” said Mr. Metheny, who, at 55, is easily one of the most enterprising jazz musicians of his generation. He has worked in an array of settings, from folkish duos to boppish trios to the sprawl of the Pat Metheny Group.

But robots were a new element, and Mr. Metheny seemed eager to explain himself. He did so in the midst of preparations for a grueling tour, which began February 1 in Champagne, France.

Mr. Metheny, who grew up in Lee’s Summit, Missouri, traces his intrigue with musical automation to an antique player piano in the basement of his grandfather’s house in Wisconsin. Later he learned about orchestrions, the pneumatically driven mechanical orchestras that flourished in the 19th century, before the advent of commercial recording. Though impressed by the mechanisms, he was struck by their musical limitations. “I thought, ‘Why couldn’t it be something else?’ ” he said. “Honestly it struck me as such an obvious thing to do. I’m kind of stunned nobody’s really approached it.”

It was about five years ago that he began to sense that the technology for a modern orchestrion was in reach. Mark Herbert, his longtime guitar technician, had designed a mechanical instrument with solenoids, which employ electromechanical rather than pneumatic energy.

Mr. Metheny’s interest led him to Eric Singer, an engineer and musician in Brooklyn doing similar work with a group he called Lemur (League of Electronic Musical Urban Robots). Soon Lemur had been commissioned to build an orchestra. “Being Pat Metheny with his grand vision, he wanted one of everything,” Mr. Singer said.

Then there was the music, some of which Mr. Metheny had composed ahead of time.

“None of it worked,” he said. “It didn’t feel good, it didn’t sound good. It wasn’t happening.” So he started over. “I very quickly had to find out what they were good at,” he recalled, referring to the robots. “What can they do, what can’t they do? And there’s a whole bunch that they can’t do. But I kind of wrote for their strengths.”

Remarkably, “Orchestrion,” recorded in October, shows few traces of herky-jerky compromise. “Entry Point,” the first tune completed, is a study in subtle undulation. The album’s only truly awkward moment occurs in “Soul Search,” during a flirtation with swing - not a robot strength, it turns out.

“I anticipate this tour as being a deeply character-building experience,” Mr. Metheny said. Leif Krinkle, a Lemur robot builder, was inspecting equipment nearby, as was David Oakes, Mr. Metheny’s technical director of many years, who will run the tour.

“Some of these things aren’t done being built,” Mr. Oakes said. He pointed to one input mechanism. “That’s hardly road worthy: a twoby- four with wires taped to it. .”

“Looks like a big to-do list to me,” Mr. Oakes said.

“Me too,” Mr. Metheny agreed. But he was grinning.

The guitarist Pat Metheny with his orchestrion, a musical machine featured on his new album. / JIMMY KATZ