“That was gorgeous. Really wonderful. I wouldn’t change a thing.”

Mignon Dunn, the distinguished Memphis-born mezzo who made her Metropolitan Opera debut nearly 35 years ago, was all smiles as she addressed soprano Rosemarie Caronna.

Both women were on the stage of the Colony Theater in Miami Beach Tuesday evening. Dunn was conducting a public master class for the International Institute of Vocal Arts, a five-week talent-honing enterprise being presented in conjunction with the Concert Association of Florida and New World Symphony.

Caronna had just performed Vissi d’arte, the aria sung by the heroine in Puccini’s Tosca as she contemplates a choice between honor and the death of the man she loves or shame and the sparing of his life.

The audience was liberal with its cheers and applause, which Dunn joined heartily. Then, almost as if an afterthought, the mezzo said, “There are just a couple of tiny things I might suggest.”

Twenty minutes later, almost every measure of Caronna’s performance had been carefully dissected. Her tendency to scoop into some notes was brought under control; her approach to the aria’s climactic point — “That’s your money note,” Dunn said — was strengthened.

The soprano was told to relax her arms, which in turn would relax her neck and throat. And to keep from clasping her hands in front of her as she sang. And to think more about what she was singing — “You’re trying to see if you can stop God from letting this happen to you,” Dunn said.

Caronna was not transformed magically into an entirely different singer, but, as she responded to Dunn’s advice, the audience could hear new sounds, phrases, nuances.

After New York mezzo Andrea Abushady sang an aria from Saint-Saens’ Samson et Dalila, Dunn asked her to describe Dalila’s motivations. When Abushady talked vaguely about pleading to the gods, Dunn responded: “I wouldn’t think of any gods at this point; I’d think of something else.”

It was clear that Dunn was referring to, well, earthier inspirations, and that sent the audience tittering. “What are you laughing at,” she asked with mock innocence. Abushady got the point and tried again. And a touch of sensuality began to color her singing.

Dunn is also doing this sort of vocal molding in private sessions throughout the institute, along with several other faculty members, including some Met colleagues. She approaches her task not with the widely held notion that the opera world is having a terribly dry spell, voice-wise. Instead, as she told the master class audience, “We are living in another ‘golden age,’ as far as young singers are concerned.”

In an interview after Thursday evening’s concert of semi-staged operatic excerpts, Dunn reiterated that view.

“There are wonderful voices coming along. I’m not saying that they are glitchless; they are not all ready to sing onstage tomorrow. And sometimes the singing gets a little too slick, a little generic. But I do a lot of judging (competitions), and I’ve given master classes all over the world. And, with all my heart, I can say I’ve heard some amazing young talent.

“A lot of singers haven’t been taught to go slow enough to learn the music correctly. They might not have been shown how to take an operatic role apart, to see how the character relates to other people in the opera. They have to learn to trust the music, not to do sloppy things. It’s all in the score.”

Dunn said she had “some fairly hard taskmasters” herself when she started singing. (Her teachers included noted contralto Karin Branzell.) She applies the same pressure now to budding vocalists.

“If they learn to sing the music correctly, how to get to the notes correctly, then they can have the freedom to be themselves.”

For her part, Dunn has long wanted the freedom to do comic roles, but she has been typecast in heavy parts. Next season, she will get her wish, performing in Verdi’s comedy, Falstaff, for the first time. “I’m looking forward to that,” she said. “I’m really a hoot.”

PERFORMANCE INFORMATION

The International Institute of Vocal Arts continues through July 8. Next week’s events include a program of German music at 8 p.m. Tuesday at the Colony Theatre, 1040 Lincoln Road Mall, Miami Beach. There will be selections by Schumann, Mendelssohn, Wolf, Mahler, Strauss and Korngold.

There will be a program of scenes from Lucia di Lammermoor, Werther, Falstaff and Madama Butterfly at 8 p.m. Friday at the Lincoln Theatre, 555 Lincoln Road Mall, Miami Beach.

Excerpts from Don Giovanni, Rigoletto, La Boheme and Tosca will be performed at 8 p.m. June 29 at the Lincoln Theatre. There will be a night of operatic spoofs, Broadway tunes and more, performed by students and faculty, at 8 p.m. July 1 at the Lincoln Theatre. Mignon Dunn will prepare and host the final concert at 8 p.m. July 8, also at the Lincoln.

The master class with baritone Sherrill Milnes has been changed from July 6 to 2 p.m. July 1 at the Colony Theatre.

For free tickets, call 523-6116 (Broward), 532-3491 (Dade).