Heard is a passive word for Frank's role. The format had him sitting in the front row of the seats in the school's auditorium while students played works that they had been polishing.
At the end of the selection, he moved to the stage, complimented the player and offered suggestions. A second piano stood beside the student's, and Frank illustrated his ideas at that keyboard, sometimes playing alone, sometimes playing with the student.
He brought to the sessions the essence of nearly a half-century of performing. Robert Capanna, director of the Settlement Music School, said, ''Our faculty is, by its very nature, aimed at teaching the music. The idea behind having a distinguished artist is to give the students the point of view of the performer, someone who knows how to project and adjust in order to reach an audience. It's another viewpoint."
Among the pianists who played for Frank was Mark Lazarev, 17, a Russian- born musician now living in Wynnewood. Tall and scholarly-looking, he put the music for Beethoven's "Les Adieux" Sonata on the music rack and proceeded to play the work from memory.
At the end, Frank took the tone of a colleague, admiring the playing and Lazarev's knowledge of the music. "But, it is too pale," Frank urged. ''There must be more singing here. . ." and he played a phrase from the beginning. "Or, at least, speaking. It must be eloquent."
Frank was playing at the second piano, citing examples, pointing out intervals and modulations, singing in a big voice. "Loneliness! Loneliness!" he called over Lazarev's playing.
As Lazarev went back through the music, his playing expanded - sometimes urged by Frank's singing, sometimes by Frank's hands at the second piano. Afterward, Lazarev was smiling quietly while his teacher, Sophia Levenson, chatted with him in Russian.
"This is my first time to play for someone like this," Lazarev said later in English. "It is a great experience." He will continue his studies next year at Oberlin Conservatory in Ohio.
Capanna said the master classes have a quality of risk about them. "The teacher does not know what music the students will play until he walks in. They secretly hope he won't know their piece, and they are always impressed when they see someone like Frank who can play it all from memory, knows its history, its every detail.
"When (pianist) Jerome Lowenthal came (two years ago), he not only knew every piece, but he prefaced each one wih a 10-minute talk in which he placed it historically, stylistically and even socially. You notice that Frank has a strong view of performing baroque music without having to be doctrinaire."
Frank heard a young trio - Ben Esner, violin; Nathan Sabatino, cello, and Clara Kim, piano, - and when he began to discuss their performance, he played the piano part and added cello and violin lines on the piano to illustrate his points.
His message to the three was that Bach is a shrine. "No matter how well you play, it is never as good as it can be played," he said, smiling.
"Keep it light," he cautioned the pianist. "Remember, Bach did not write any of the music for the right hand that you have in the score. He wrote the bass line and someone else wrote that. Don't make a big thing about what Bach didn't write."
Then, as the trio started again to employ Frank's ideas, Frank called out: ''Swing it a little."