By Noah Schaffer

As a cappella singers, they have taken their musical ministry — and its repertoire of 500 songs — to streets, subway stations, picnics, community clean-ups, and anywhere else they might find an audience who appreciated a musical message.

The Harmonizing Stars of Boston. Photo: courtesy of the artist.

Boston’s traditional gospel scene is a rich one, but it also seems a bit … hidden. Many of the finest groups in the city sing to a small network of churches and programs that draw loyal but relatively small audiences.

The Harmonizing Stars of Boston, however, have taken a different approach, with an accent on visibility. As a cappella singers, they have taken their musical ministry — and its repertoire of 500 songs — to streets, subway stations, picnics, community clean-ups, and anywhere else they might find an audience who appreciated a musical message. The group celebrates its 50th anniversary on Sunday at 4 p.m. at Zion Holy Temple Church, 79 Stanton Street, Dorchester, MA.

“It’s a family thing,” explains James Bruce, one of the three original members still with the group. Bruce was eight when Harmonizing Stars was formed. At one point, there were five Bruce brothers and nine total members. Today, James is joined by his brother Jonathan, their uncle and fellow original Jonathan Bradshaw ,and family member Andre Wright. “My great-grandfather, Evangelist Herbert Hall, was the pastor of the church, and during the service he would have the children come up and he would teach us songs and how to read scripture,” says Bruce, remembering the group’s formation in Dorcester’s Church of God & Saints of Christ, which it still is a part of today.

The Harmonizing Stars quickly found itself in demand as word spread about the group of young boys who boasted memorable vocal ranges. They were booked to sing on programs with older Boston gospel mainstays like the Bibletones and the Spiritual Wonders. Too young to drive, the members would scramble to catch MBTA buses to their engagements around Roxbury and Dorchester. “That’s where we came up with our theme song, running up and down trying to catch the bus,” recalls Bruce.

As the members became grown men, the group continued. “It was fun, and there was also a real purpose because we love the Lord,” says Bruce. “The fact that we’re a cappella meant that our voices became the instrument — we’re just so tuned into each other’s voices that we can be in four parts of a room and not even see each other, but we could still sing together.”

In 2008, when the economy cratered, the Harmonizing Stars found an entirely new audience when they became licensed MBTA performers. The group became regular entertainers in the passageway of the Downtown Crossing station, which connects the Red and Orange lines. “The acoustics were so marvelous,” recalls Bruce. “People would miss their train so they could hear the remainder of the song we were singing! And we met so many people. Some gave us subsequent bookings at their events, and others just appreciated the joy and healing that we provided.”

Although the group members have written hundreds of original songs, they have also found it effective to make a connection between the gospel tradition and the harmonies of doo-wop and Motown. (Both Bruce brothers have separate musical careers as R&B recording artists.) “We realized that the older people were listening for the message, and the younger people listened to the beat,” says Bruce. “So we would take some tunes that people might recognize, like ‘In The Still of the Night,’ and change the words to reflect our message of loving Jesus Christ.”

To celebrate 50 years, the group will be doing something different on Sunday. They will feature live musicians on a few of their selections. “We’ve been rehearsing and it’s like learning another language,” says Bruce. While they are excited about the new challenge, he is sure of the bedrock artistry of the Harmonizing Stars: “We recognize the true value in our singing a cappella. We don’t need to worry about who will bring the equipment, and we don’t even need microphones. We can strike up a tune anywhere.”

Over the past 15 years Noah Schaffer has written about otherwise unheralded musicians from the worlds of gospel, jazz, blues, Latin, African, reggae, Middle Eastern music, klezmer, polka and far beyond. He has won over ten awards from the New England Newspaper and Press Association.