Music is important in all of August Wilson’s plays, but particularly so in “Seven Guitars,” the first in the Signature Theatre Company’s three-play tribute to the playwright, who died last year.

“August loved the blues,” Bill Sims Jr., who wrote the music for the production, which opens tomorrow, said. “It was what he grew up with. It was the music of the people he loved.”

“Seven Guitars” is Mr. Sims’s second Wilson play, as well as his second collaboration with the director Ruben Santiago-Hudson. The first was Wilson’s “Gem of the Ocean,” which Mr. Hudson directed last year at the McCarter Theatre in Princeton, N.J.

“Seven Guitars” focuses on a young blues musician, Floyd Barton, whose longing for stardom and whose exploitation by a white manager and white record producers threaten to destroy him. Floyd’s hit song, “That’s All Right,” is played several times during the play. Another character, the Haitian immigrant King Hedley, is named after a blues singer, King “Buddy” Bolden, and Hedley has a dream that Bolden will someday appear to him, bringing him his inheritance.

Although “That’s All Right” is a real song, recorded by Jimmy Rogers, Mr. Sims made original recordings of it and all the other music in the play. Most of the music is heard during moments of silent action or during scene changes. “One thing Ruben doesn’t believe in, and I don’t, either, is putting something over August’s words,” Mr. Sims said.

When he’s not working on a play, Mr. Sims is a full-time musician. He finds fewer places to play blues these days than he used to, though. “Blues music in America is at an all-time low,” he said. “The clubs have disappeared, the work has disappeared. I spent a lot of time learning to play all these different instruments — banjo, accordion, piano — and all these different types of blues, with no place to put it.”

Wilson’s plays, though, give him a place. “Like he does with a character, he makes it worth something,” Mr. Sims said of what Wilson does for the blues. “Every character, whether they’re middle class or lower middle class or just a garbage man, their life is worth something. And that’s what he does with my music.”

Wilson’s plays are written to be very historically specific. “Seven Guitars” takes place in 1948, and Mr. Sims wanted to make sure that all of the music sounded like it was from that period. That meant using specific instruments: an acoustic bass rather than an electric bass, and a National steel guitar — which has cone resonators, designed so that it can be heard above the band, in an era before amplification.

The musicians Mr. Sims works with know their history, too. The trumpet player who was recording the Buddy Bolden song, for instance, “didn’t bring in a trumpet; he brought in a cornet — which Buddy Bolden played. It has a much warmer sound, a very different sound,” Mr. Sims said. “He actually had a cornet from 1890-something.”

Mr. Sims said he finds it easy working with Mr. Santiago-Hudson, a fellow musician and a friend. They met in 1998 on a play called “Deep Down,” in which Mr. Santiago-Hudson acted and played the harmonica and for which Mr. Sims wrote the music and played guitar. Later, Mr. Sims composed the music for Mr. Santiago-Hudson’s first writing attempt, the play “Lackawanna Blues.” Even when they’re not working together, Mr. Sims said, the two men talk on the phone several times a week and get together frequently to play.

Mr. Sims, who is 57, grew up with music — mostly church gospel and blues. His father, who is still alive, is a minister, but before that he was a blues singer. “Unlike a lot of other churches, where the blues was the devil’s music, we were never taught that in our house,” Mr. Sims said. “My dad, to this day, I’ll take out my guitar and he’ll say, ‘Let me see that, it’s not tuned right.’ And he’ll tune it and play some blues.”

Like many art forms, the blues is suffering as its audience ages, Mr. Sims said.”There was a time when you could play a different blues club every night in New York for, like, two weeks,” he recalled. During the 1980s, the fans were making lots of money and living it up. “They were supporting the clubs, going out, having a good time, doing things to keep them awake all night,” Mr. Sims said. “Now they’re 60, 65 years old. They don’t go out at night, so there’s no market for it. They maybe go to see B.B. King or Buddy Guy. They go out, spend two or three hundred dollars on dinner, and they’re home by midnight.”

Mr. Sims still finds a few clubs to play in, including Terra Blues and the 55 Bar, both in Greenwich Village, and Rodeo Bar in Gramercy. On September 9, he’s playing in Battery Park along with James “Blood” Ulmer and the Memphis Blood Blues Band, as well as the guitarist Vernon Reid, in a tribute to Mr. Wilson jointly presented by the River to River Festival and the Signature Theatre.

Ironically, to the extent that blues survives, it’s partly because of white stars like Eric Clapton and the late Stevie Ray Vaughan. In an audience discussion after an early preview of “Seven Guitars,” Mr. Santiago-Hudson joked about having to hire a white harmonica player, Matthew Skoller, to play the really hard harmonica parts in the play. (Mr. Santiago-Hudson plays the easier ones.)

Although Mr. Sims said he finds it strange to observe young black musicians trying to imitate Vaughan — “You have black guys trying to play like a white guy, who was trying to play like black guys,” he quipped — he is philosophical about the white takeover of the blues.

“As long as somebody keeps the music alive, I’m happy. We have no one to blame if, 50 years from now, the greatest blues player who ever lived is Stevie Ray Vaughan,” he said. “If you leave gold layin’ around, somebody will come pick it up.”

Until September 23 (555 W. 42nd St., between Tenth and Eleventh avenues, 212-352-3101).