HALLOWELL — A cappella singing groups will converge at the Old South Congregational Church at 3 p.m. Sunday, Sept. 27, for a concert to raise money for repair of the church’s pipe organ.

The historic organ was built in 1885 by Boston’s premier organ company of that time, Boots & Hastings, and was last fully refurbished in 1974.

Featured will be the Maine-ly Harmony women’s chorus based at Togus VA, under the direction of Kathy Greason. Maine-ly Harmony performs frequently throughout central Maine and participates annually in singing contests in the United States and Canada. Quartets from the chorus will also perform.

Maine-ly Harmony will be joined by two men’s quartets, Maine Stream and Back Bay Four. Maine Stream is a new quartet of experienced singers based in Waterville. Members are Jay Daniels, Darrin Cates, Bill Rutledge and Dick Kromer. Back Bay Four, a past division champion in the Barbershop Harmony Society, has won numerous awards. Singers for this performance will be Darrin Cates, Walt Dowling, Jay Wiley and Robb Sorensen. Curt Roberts of Wiscasset will be master of ceremonies.

The groups will perform music, old and new, arranged in four-part harmony.

Admission is free, with money for organ repair to be raised through a free-will collection during the concert. Old South Congregational Church is at 135 Second St.