Twenty-five years ago, a family of strangely coiffed, yellow cartoon characters scurried home to gather in front of their TV for the first time. The Simpsons has since become an animated thread in the fabric of American pop culture — and, starting from the angelic chord and cascading harp of its opening theme song, the show's music has been an integral part of its humor and heart.

On Sept. 12, 13 and 14, the L.A. Philharmonic will celebrate that music in its final Hollywood Bowl concerts of the season.

Hosted by Hank Azaria (voice of Apu, Moe and countless other Springfield residents), it's the first event of its kind, with performances by members of the voice cast as well as Conan O'Brien (who will perform “The Monorail Song,” from an early episode he penned) and “Weird Al” Yankovic.

Danny Elfman wrote the iconic theme music back in 1989. His invitation came from Simpsons creator Matt Groening — who, as a rock critic years earlier, had panned a concert by Elfman's band, Oingo Boingo, in the Los Angeles Reader. Elfman was so annoyed that he wrote a scathing letter to the editor.

Now the highly regarded composer of scores for films such as Batman and Pee-wee's Big Adventure, Elfman was courted and shown an early animation of the iconic title sequence.

“I really hated contemporary TV themes back then,” Elfman says. “I said, 'Look, if you want something contemporary and cool-sounding, I'm the wrong guy. But if you want something really retro, my sense of this is it should be like the Hanna-Barbera theme that never was.' It had that kind of Flintstones energy to it.”

“The opening title basically is The Flintstones,” Groening admits. “Fred Flintstone getting off work and coming home — same thing with Homer Simpson — to watch TV.”

“We really hit it off in that meeting,” Elfman says. “Nobody mentioned anything about having met in the past. Then as I was leaving, we shook hands and he said, 'By the way, you may not remember, but you once took me to task over…' I said, 'Oh yeah, I remember.' ”

Having reconciled with Groening, Elfman drove home and a tune immediately leapt into his mind. “As soon as I saw the sequence, I heard the 'bah-bah-bah-BUM-bah-bah-bah…' ” he says. “I drove home really fast because I didn't want to lose it. I ran down the steps of my studio and I made a cassette, and sent it out the same day. That demo was, essentially, The Simpsons theme. There is some great cosmic irony that it's the quickest and most easily conceived job of my life, and it became probably the most famous thing I ever wrote.”

Of course, there's much more to the music of The Simpsons than its theme. Week after week, for more than 550 episodes, Alf Clausen has written the underscore and most of the songs since the very first “Treehouse of Horror” episode. He has scored the show (which he records in town with a 35-piece orchestra) like a straight drama — never treating Homer Simpson as a buffoon. It's part of a philosophy he learned from a former bandleader: “You can't vaudeville vaudeville.”

“Which simply means that you can't play a funny situation with funny music and expect it to be any funnier,” Clausen explains. “So when I have a scene to score, I will score it as if it's real-life stuff. And then when the joke happens, I always get out of the way and let it play in the clear … because that's the payoff.”

Both the score and the vast canon of memorable songs — from “We Do (The Stonecutters Song)” to “Señor Burns” to a Broadway sendup of Planet of the Apes — further the show's lampoon on American life. But they're also part of its tender core. “The Simpsons, in its own way, has an earnestness to it,” Azaria says. “Whereas Family Guy and South Park are much more heavily satirical, The Simpsons is somewhat satirical — but it's also kind of delivering the sweet, old-fashioned music it's making fun of at the same time.

“If you watched a great episode and somehow magically turned off the music,” he adds, “it would feel really weird, and not half as good.”

THE SIMPSONS TAKE THE BOWL | Hollywood Bowl, 2301 N. Highland Ave., Hlywd. | Sept. 12-14 | hollywoodbowl.com