Producing platinum-selling albums wasn’t always in the plans for David Foster, but it didn’t take long for him to make the shift from playing on other people’s sessions to producing other artists.

“I was always planning for the next phase,” he tells Variety. “As a rehearsal pianist, I was strategizing to become a studio musician. And when I was a studio musician, I was strategizing to become an arranger and a producer.”

Seeing session players have their day in the sun — and then not — carried little appeal. “My idols growing up had gone from single scale to double scale and triple scale, and then back to single scale. That wasn’t the life for me.”

So in 1979, after building his rep playing on other people’s hit records, Foster made a conscious decision to give up working as a session player and begin producing. “I went from making six figures in 1978 to making just $5,000 the first year producing. That was pretty intense.”

Foster produced three albums in 1979, all of which “stiffed,” as he puts it. “I was just about ready to give up and go back to session playing. I thought I wasn’t a good producer — I had in my head that producing was all about getting great musicians together and pounding out tracks. But producing, of course, is about songs and it’s about vocals. It’s not about the band. It took me a while to figure that out.”

Having worked three or four years as a session man, Foster began to draw on his experiences working under different types of producers — some good, some not so good. “The bad ones were often leaning on me to help produce their records,” he recalls. “And I was only too happy to help these guys out, with, ‘What about this chord? What about this? Try this.’ Then I realized that I could do that.”

He also noticed something else that was important in his new role. “I learned that you don’t have to be a great musician to be a great record producer. That’s why I was making bad records — I was so concerned with the music being right that I didn’t care about the singers. And so I learned from the good producers that they cared about the singer. The singer is god.”

An early influence was legendary composer Johnny Mandel, who gave Foster important advice about arranging. “He said, ‘My best advice is stay the fuck away from the vocal.’ Leave a hole for the vocal — don’t write a string line on top of a vocal that’s in the same frequency range as the vocal. The vocal is the most important thing.”

Foster began learning arranging in 1972 while he and his band, Skylark, were recording their first album in Los Angeles, for a song called Strings for “My Lady.”

“I learned some from having played in orchestras — I was a bassoon player,” he adds. “I didn’t know the ranges of all the instruments, though, so I literally would listen to records and see how low the cello would go, etc. I kinda guessed.”

He then get a boost from renowned arranger Paul Buckmaster (Elton John), whom he found in town that year at the Sunset Marquis. “I called him out of the blue and asked if he could help me, and he said, ‘Yeah, c’mon over.’ We laid down on the floor, and I brought my scores over. In four hours, the guy showed me his stuff.”

His skills have only increased with time and experience. “He just sits down and, within hours, comes up with the most incredible arrangements,” says Michael Buble. “They just flow out of him. He doesn’t even have to think about it.”

Adds Barbra Streisand: “He has so many musical ideas. I could entrust the entire arrangement to him.”

Andrea Bocelli agrees. “David has a fantastic feeling for getting the arrangements right. He really is a magician, and he has the gift to make everything he tries beautiful.”

Playing on records he produces taught Foster yet another important lesson. “You have to completely forget about the fact that you’re the musician that played on it,” he says. “Because there’s a tendency, for example, if you play a great piano part, to go, ‘Oh, I want that louder.’ You have to think of it just as ‘a guy played that, and it’s too fricking loud, and it’s too busy.’ You have to divorce yourself from the fact that you’re that guy.”

Foster’s early success as a producer included discs with groups like the Tubes (“She’s a Beauty”) and Alice Cooper, though he admits, “I’m certainly not a rocker.” He had mammoth hits with Chicago (“Hard to Say I’m Sorry,” “Hard Habit to Break”) and Lionel Richie (“All Night Long,” “Hello”), among others, in the 1980s.

By the late ’90s when the InSyncs and Backstreet Boys were beginning to come into vogue, Foster realized he would need to make a shift if he was going to keep up. “I loved that music, but I knew I didn’t know how to do it. So it was either shrivel up and disappear or go a different route.” He decided instead to focus on singers like Bocelli, Josh Groban and Buble.

“I make music for adults,” Foster explains. “I don’t know how to make music for kids anymore.”

Says session musician Danny Kortchmar, a former bandmate of Foster’s: “That was a perfect match for him, working along the lines of more legit producers, as opposed to the animals that were doing rock and roll.”

Those associations, particularly for younger artists, have been fruitful ones. Besides producing blockbuster sales, Groban values Foster’s role as a mentor: “He pushed me further than I thought I could go when I was younger and taught me so many valuable lessons about music, the business and life.”

Buble also has grown as a professional through his work with Foster. “My musical director and writing partner, Alan Chang, has pointed out many times — what we’ve learned spending time in the studio with him we couldn’t have gotten in 20 years of school,” in particular Foster’s way with studio musicians. “In a 70-piece orchestra, he knows every one of them by name, knows their families, and at what each excels in.

“It’s actually scary. I’ve been in the studio with him with and an orchestra, and he’ll stop everything suddenly and say, ‘Third viola, you’re out in the 6th bar.’ He sees music the same way Neo sees The Matrix. Things just slow down for him and he hears everything.”

As with any good producer, Foster stays on top of what is specific to each artist when crafting their records.

“He’s got a producer’s natural instincts,” says Quincy Jones. “He knows what pieces to put together and where to put them. And he puts an artist where they should be. And that’s what a producer’s main job is.”

He also has a firm vision of what he sees for an artist, Streisand adds. “He knows what he wants, and won’t stop till he gets it. I love that about him.”

Getting the performance he wants out of an artist in the studio is something Foster says he learned from watching Jones at work. “Quincy is somehow able to get what he wants without pushing too hard. He commands 110% out of you, but it’s through motivation. I don’t know how he does it, but I hope I’m able to do that a little.”

Jones supplies the answer: “It’s through love and respect and knowing the range of what the artist is all about. If you’re asking them to take a leap without a net, you’d better know what you’re doing. And David does.”

That doesn’t mean cow-towing to an artist. “He’s honest, but he’s never mean,” Buble notes. “But he’s not precious with you either.”

Nowhere is that respect and skill more evident than in Foster’s work with Bocelli. “David has an irrepressible musical sensibility that enables him to understand what the public wants to hear better than anyone else,” the singer says.

Having spent the greater part of his career recording classical music, Bocelli notes of his more recent success in pop: “David is the only connection I have in the pop field that I totally trust without any reservation.”

Not to say that the two, whom Bocelli describes as having developed a “spontaneous friendship,” always see eye to eye. “I push him, just like anyone,” Foster points out.

Buble relates that he has had a similar experience. “I like the rawness of soul, complete with the flaws that make it so beautiful, and David’s a perfectionist. We have these wonderful disagreements that have resulted in bringing my music to a new place.

“He says ‘Good is the enemy of great. Anyone can be good.’”

Foster is more than happy to share what he knows with young producers, like RedOne (Jennifer Lopez, Lady Gaga) and Dr. Luke (Rihanna). “They want to know what I know,” he says, “even though they’re hitting it out of the park on a constant basis.”

Notes Red, “Every song that David was involved in was perfect ear candy, with memorable, special melodies that excited a kid, like me, who did not speak English.”