Los Angeles ? When composer Burt Bacharach went on the road in 1968 with the tryout of the stage musical “Promises, Promises,” he got pneumonia, barely avoided a nervous breakdown and suffered the taunts of producer David Merrick, known in theater as “the abominable showman.”

When Bacharach’s new musical, “The Look of Love: The Songs of Burt Bacharach and Hal David,” premieres today on Broadway, Bacharach says he’ll be in the audience “as a spectator.”

This undoubtedly will come as a surprise to members of the music trade, who consider Bacharach the ultimate control freak. He is known to exact repeated rehearsals for his concerts and recordings and to tweak orchestrations until they fit his concepts down to the last note.

But for “The Look of Love,” Bacharach says he “just tried to control a few things: I sent recordings, and I approved the drummer and the bass player. The rhythm section is very important in my music.”

“The Look of Love” offers a reunion of sorts for Bacharach and lyricist David, whose string of hits lasted longer than those of any other songwriting duo this side of Rodgers and Hammerstein. Just the titles — “Alfie,” “I’ll Never Fall in Love Again,” “Walk on By,” “Raindrops Keep Fallin’ on My Head,” “I Say a Little Prayer,” “What the World Needs Now,” “Do You Know the Way to San Jose?” — bring melodies, and memories, to mind.

Scott Ellis, director of “The Look of Love,” said he grew up with Bacharach’s music. “And it’s still as popular today as it was 40 years ago. Every generation seems to be discovering it, which says a lot about the work,” Ellis said.

“That sound — there is nothing else like it. When you hear it — you go, ‘Burt Bacharach.’ People react to it.”

Yet in 1973, the hit-making partners shocked the music world by breaking up. Bacharach places the blame on the remaking of the movie “Lost Horizon.”

The misbegotten redo started out much the same as the 1937 classic that starred Ronald Colman. But when the scene changed to Shangri-La, the filmmakers peppered the movie with song and cast it with nonsingers who struggled haplessly with the tricky, offbeat Bacharach rhythms. Bacharach’s desperate efforts to improve the sound led to his being barred from the recording stage.

Nonetheless, he helped promote “Lost Horizon,” even touring with 14 kid singers from the movie. Then it opened to brutal reviews and little business, and he fled to his beach house near San Diego.

“I didn’t want to write with Hal or anybody,” he says. “It became a problem because we had a commitment to record Dionne (Warwick, his favorite singer) for her next album. I didn’t feel like doing it, and that’s wrong.

“Dionne didn’t get recorded, and she sued us. And Hal, to protect himself, sued me. It was just ugly and stupid on my part.”

In time, the spat was settled. But Bacharach worked with other lyricists, including his third wife, Carole Bayer Sager, with whom he won the 1981 Academy Award for the “Arthur” theme song. He had won two in 1969 for the score and song (with David) of “Butch Cassidy and the Sundance Kid.”

Today, Burt Bacharach, 74, lives in a three-story French Provincial house in the upscale Los Angeles enclave of Pacific Palisades with his fourth wife, Jane, a former ski instructor, and their son and daughter, Oliver, 10, and Raleigh, 7.