Hannibal Lokumbe calls his new work, "One Land, One River, One People," a "spiritatorio." Commissioned by the Philadelphia Orchestra, it's less a concert piece than a spiritual explosion - a gumbo of blues, jazz, spirituals and joyful rhythm.

Yannick Nezet-Seguin will conduct the work this weekend in a program that will begin with Copland's familiar "Appalachian Spring" and Sibelius' stirring "Finlandia." "One Land" is scored for soprano Laquita Mitchell and tenor Rodrick Dixon, plus three choirs: the Delaware State University Choir, the Lincoln University Concert Choir and Morgan State University Choir.

The title of Hannibal's piece, composed in three movements he calls "Veils," represents the physicality, blood and spirituality of humanity, an idea he says came to him from his great-great-grandmother, a Cherokee shaman.

"Out in the forest of Texas, I have a huge cedar table that my son and I built," said Hannibal, who lives near Austin. "I was lying on it and looking at the Milky Way, and her spirit came to me. She was short, with very long hair - beyond beautiful, with a look of peace. She gave me the basis, with my text and the music each informing the other.

"I always use Veils, because we usually are certain that we understand something, but we don't have a clue. When that indestructible, unnameable power opens our eyes to something, a Veil has been lifted from us and we're never the same."

The soprano and tenor perform a dialogue between Amma and Nommo, with Amma the grandmother, or celestial figure, informing Nommo, representing humanity, of life's truth. Hannibal was slow to admit, with a final hearty laugh, that it's really about his grandmother's spirit voice and his own constant hope of understanding life. There's a soaring piccolo part, a translator of what Amma is saying to humans, what the spirit says to the flesh.

Nezet-Seguin led the first of the three Veils last January at Girard College, during the Martin Luther King Jr. Day of Service. Last week, in between rehearsals at Opera de Montreal for Strauss' enormously challenging "Elektra," he took a few moments to share his enthusiasm for Hannibal's intent.

"I had heard recordings of his music and found he has such a gift for making the voices speak, a talent very rare in this world," Nezet-Seguin said. "We had a long conversation, mostly about life more than music, and in his eyes I see suffering and hope.

"Of course, I'm always in love with vocal sounds, and in his music I hear his own religious background, spirituals, jazz, the tradition even of Baroque music, in a unique voice. It's very tricky for the singers as well as the musicians, and it's a tribute to how our orchestra is able to be flexible in many styles."

Flexibility is important in growing the audience, the conductor continued.

"We're trying to touch the younger generation, an important part of our city of music, and I have been working with Play On, Philly! through our bassist Joseph Conyers and [its founder] Stanford Thompson. I want the orchestra to be at the center of connections between all our different communities."

Hannibal's previous works - "African Portraits," "One Heart Beating" and "Can You Hear God Crying" - looked back to the cruel history of his people. His grandfather was taken from the Sahara to Liberia and sold in Charleston, S.C.

Hannibal himself remembers working the cotton fields in 115-degree heat and hearing the singing, the outpouring that kept people going.

The text of this piece is more about healing, thanksgiving, universal connection in our common future, less reflections on past injustice.

The orchestra has arranged a wealth of outreach programs for Hannibal, who always visits schools and often tried out pieces for prisoners.

He played the Philly jazz scene as a trumpeter in the 1970s, eventually doing five years with the genius arranger Gil Evans, whom he calls "one of the joys of my life."

He said of his horn playing, "I don't hear trumpet when I play, I hear B-flat tenor saxophone, and [I] made a trumpet with a bigger bell so I could get those lower notes and sonority in the bottom.

"Lee Morgan told me that John Coltrane told his sister to lock the door, he was going to kick his habit and he did it cold turkey. He said God saved his life and told that story in 'A Love Supreme,' which had a profound effect on me. Trane influenced me more than anyone.

"I love to go over to the Creative Arts Morgan Village Academy, in Camden, where their jazz band wins top honors. And, in prison, my great pain is seeing people incarcerated, but people's thinking can be more restrictive even than iron bars. We're too unique a creation not to celebrate being alive.

"My mentor, James A. Wilson, who taught me everything I needed to know about music, will be there. He gave me three hours after school each day in eighth and ninth grade, encroaching on his time with his daughter, who is bringing him. That's why I never charge for a private lesson."

Is it easier to compose when you know that the orchestra can play anything, he was asked?

"It has to be a factor - an extraordinary palette at my disposal - and it's a great privilege."

He added, "I'm bringing the great drummer Cecil Brooks III [to perform in this weekend's concerts], but was disappointed that the composer didn't write a trumpet part for me."

Verizon Hall, Kimmel Center, Broad and Spruce Streets, 8 p.m. Friday and Saturday, 2 p.m. Sunday, $40-$147, 215-893-1999, kimmelcenter.org.

Tom Di Nardo has been covering classical music and dance for the Daily News since 1982. Email him at tomd322@yahoo.com.