MusicDown in New Orleans, due in stores late January, is the latest CD by a legendary gospel group: The Blind Boys of Alabama. The vocal harmonies find a Crescent City groove on cuts that feature accompanying work by Allen Toussaint, the Preservation Hall Jazz Band, pianist David Torkonowsky, bassist Roland Guerin, drummer Shannon Powell and the Hot 8 Brass Band.

These stellar artists lay down a swinging signature that puts the Alabama group on a new threshold. That is not a chauvinistic form of praise. The Blind Boys have four Grammy Awards and their version of “Way Down in the Hole” was the theme song of the HBO crime series, The Wire. This new CD marks a turn in the singers’ unfolding path in pop culture. Toussaint’s piano licks on “Down by the Riverside” have ringing tonal currents and the Preservation Hall band adds warmth in the rhythm on an ethereal version of “Uncloudy Day.”

The rolling voices of the singers echo the down-home spiritual and gospel singing that’s heard today mostly in small choirs or quartets, when it’s heard at all. In contrast, gospel music is a huge world of composers, arrangers, musicians and mass choirs feeding on new material. The Blind Boys formed in 1939 at the Alabama Institute for the Negro Blind and traveled on the gospel circuit for decades. Two founding members, Clarence Fountain and Jimmy Carter, made the long haul and work now with Bishop Billy Bowers, Joey Williams, Ricky McKinnie, Bobby Butler and Tracy Pierre.

The beauty of this tradition lay in its sonorous linkage to the spirituals and sorrow songs that rose from slavery to a plateau of memory in black churches of the early 20th century. The songs carried a history that rocked with a power all its own and rolled like a mighty river into the stylizations of post-World War II R&B. Yet we know far less about the roots of gospel than we do about jazz and ragtime, thanks to curious early journalists and song sleuths. The forging of a repertoire that came to be called gospel drew on the songs of memory and pastors absorbing standards, like “Amazing Grace” among others, from white Protestant hymnals. How songs were sung in white and black congregations, divided for generations by segregation, registered profoundly different meanings, as black groups went about stylistically refitting lyrics to suit the needs of a culture on the rise. “Uncloudy Day,” with its dream of a heavenly end, as sung on this CD, extends the idea of freedom sung by slaves in “Steal Away.”

The beauty of gospel singing these days is a magnet to ever-growing audiences of white people who feel a common chord in themes of the older lyrics and the emotional way they are sung. Down in New Orleans gives this phenomenon an ironic twist in the Hot 8 players teaming with the Blind Boys on “Make a Better World.” The lyrics come from the 1960s R&B composer Earl King, the hand behind the Mardi Gras Indians anthem, “Big Chief,” first popularized by Professor Longhair. It was James Booker, the brilliant, broken, dazzlingly manic keyboard prince who seized on “Make A Better World” as a standard in his performances. Hearing Booker sing “Let’s all pitch in, and make a better world to live in,” one hears the best impulses of the R&B tradition, a bouncing paean to unity. The song captured optimistic yearnings for a post-civil rights era:

You got to live and give
Care and care
Put some love in the air
And when your neighbor’s down
Pick him up
No one can live in despair
Try to pitch in
Do your thing
Make a better world to live in
Everybody sing, sing, sing …

Heard today, on a gospel CD with a gravelly voice calling the congregates to a cause of making joy, one appreciates the timelessness of Earl King’s song, which now could function as a post-Katrina call to common cause.

The Blind Boys’ down-home approach is a far cry from James Booker, with that star emblazoned on his eye patch and God-knows-what in the way of chemicals coursing through his veins, all but singing for his own redemption. Irony abounds in the sweet, almost decorous stamp the Hot 8 players bring as rhythm section to the Blind Boys of Alabama as they retrofit an urban R&B standard of a generation ago into a gospel tune of the new millennium. Thus does the river of music roll.