At his peak, Mr. Deibler simultaneously led two choral groups that he helped found - Music Group of Philadelphia, starting in 1978, and Choral Arts Society, starting in 1982 - while teaching at the University of the Arts. He frequently prepared the Choral Arts singers for high-profile recordings with the Philadelphia Orchestra under Riccardo Muti.

His work with the smaller Music Group, which he headed at the time of his death, included commissioning works from local composers including Andrea Clearfield and Margaret Garwood. In the '80s, he frequently conducted musicians from the Philadelphia Orchestra in concerts to raise awareness of nuclear disarmament.

"He had this amazing impact on people. He had many devotees," said Donald Nally, who took over the Choral Arts Society after Mr. Deibler departed in 1997.

"The early years with him were the best, and the most challenging and rewarding choral experiences I've ever had," said Sue Heckrotte, who sang with Music Group of Philadelphia for 12 years starting in 1989.

"Rehearsals were master classes," she said. At times, that "master class" element made rehearsals more like lectures, which occasionally resulted in underprepared concerts. Still, Heckrotte said, "it was a remarkable gift that he gave us."

"He was a real specialist with Hungarian and Eastern European music and did wonderful performances of Zoltan Kodaly in the native language," said Alan Harler, music director of the Mendelssohn Club of Philadelphia. "But I had been out of touch with him for a long time."

Mr. Deibler had absented himself from the music community in recent years, left his University of the Arts position in 2002, and stopped attending concerts by other organizations. His own Music Group season had dwindled to one or two concerts per year.

William R. Gatti, Music Group executive director, who announced Mr. Deibler's death yesterday, said money problems were a significant factor. Music Group last performed in May 2008; Gatti said the organization's future was uncertain.

Born in Bryn Mawr, Mr. Deibler graduated from Susquehanna University, studying both clarinet and voice, before happening onto the Kodaly Method during a 1969 summer seminar in Boston. Contacts in Hungary led to further education at Budapest's Franz Liszt Academy and Kodaly Institute, where he also was on the faculty. He spoke fluent Hungarian, German, Italian, and French.

During those years, he regularly sang in choral performances of Mozart and Haydn at the famous Mathias Church. Years later, in 1989, he brought Music Group to the Gothic structure, where he performed works by the modern Swiss composer Frank Martin.

"There wasn't much music he didn't like," Gatti said.

Although Choral Arts programs emphasized the big standard-repertoire choral works, Music Group sometimes began with little-known baroque works by Domenico Scarlatti and moved forward to the present. When programming familiar works, such as the Mozart Requiem, Mr. Deibler preferred unfamiliar editions.

He also guest-conducted the Slovak Philharmonic and Warsaw Philharmonic, touring with the latter ensemble with Vaughan Williams' Sea Symphony.

He is survived by a brother, William John Deibler. A memorial service will be held next month.