GUILFORD — It wasn’t until a friend nudged Lonnie Wescott of Guilford and whispered, “Oh my gawd, pass it on,” when the full impact of what he was about to do struck him.

Looking into a sea of more than 2,000 faces, Wescott was awed. Here he was, standing on the spacious stage at Carnegie Hall on 56th Street in New York City on May 23, waiting for his cue to start harmonizing with some 200 other voices, including fellow SAD 4 choral instructor Dee Dee Killilea.

“Understand that as a musician, this is the level you would strive for all your entire life, and to stand there on that stage where the world’s utter best have performed, you know, and to be there, I felt validated,” Wescott said this week. After all the years Wescott, a tenor, spent dutifully studying and practicing music and the ensuing years of working with students, encouraging them to strive for excellence, his Carnegie experience was a big payoff.

For Dr. Dennis Cox, professor of music in the school of performing arts at the University of Maine, it was the icing on a 20th anniversary cake. Because of Cox, Wescott and others in his group had the chance to perform in the mother of all concert halls.

Cox said a longtime friend who works for a company that coordinates all of Carnegie Hall performances had sought him out to do a concert in the hall for the past couple of years. Since he’s entering his 20th year at UM, Cox said, his friend thought the Carnegie performance would provide a really exciting platform for his anniversary celebration.

“We kind of put some feelers out to some of our alumni, and they got very enthusiastic about it,” Cox said. Some alumni sent out newsletters to determine interest in the project. A frequent guest conductor throughout the Northeast, Cox asked other conductors if their singers might be interested in participating in such a performance.

The result is history. Cox assembled a 200-voice choir to sing Mozart’s Coronation Mass. Four professionals were hired to sing the solos with instrumental music provided by the New England Symphonic Chamber Ensemble.

“It’s such a world-class venue,” Cox said of Carnegie. “It’s not only a physically beautiful place, but it has superb acoustics.” People seated in the five balconies of the hall have unobstructed views of the stage.

The trip to New York City was the first for Killilea, a soprano, who was surprised to find the hall smaller than she had imagined. “I told my kids it’s like playing basketball at the Boston Garden. It’s just the ultimate,” she said.

Cox estimated that about 70 of the vocalists were current or former university singers with a large contingent of select high school students, including a group from Cony High School. “I selected people that had strong programs. We only had, collectively, a one-day rehearsal plus a dress rehearsal to do this,” he said. Before anyone got to New York, they had to be prepared, he said.

“It was very intense before it started. Of course, I wanted to do my very best,” Cox remarked. While more difficult to conduct a choral group with soloists and an orchestra, he said it was really thrilling for him to be able to do it. “It came off just beautifully,” he said.

Both Cox and Wescott said a large part of the audience was either affiliated with the university or alumni. They provided the group with a rousing standing ovation, according to Wescott.

Before the first rehearsal, alumni presented Cox with a handmade wooden music stand with a plaque on it commemorating the university’s Carnegie Hall experience for his 20th year. “That was quite emotional,” he said.

Such performances, as well as those conducted in Europe every four years, help the university recruit the best students for the choral program, according to Cox.

For Wescott, the trip was a chance to bring back something to his students. “When I got on stage, what I was trying to do was look at everything and remember everything. I was trying to make a mental imprint of everything around me so that I would remember it,” he said.

“It was just one big sensory overload, you know, seeing old friends, singing this wonderful piece with the person I consider the finest choral conductor in the United States,” Wescott explained.