Young instrumentalists are often advised to emulate singers if they want to understand musical phrasing and expression. That’s exactly what the famous Viennese professor Schiller prescribes for Stephen Hoffman, the brash American pianist who seeks his help in Jon Marans’s touching Old Wicked Songs. A finalist for the 1996 Pulitzer Prize, the play opened last week at Merrimack Repertory Theatre.

The audience never actually sees Professor Schiller because he sends the troubled Stephen — who hasn’t been able to play for a year — to work with Schiller’s old friend, singing teacher Josef Mashkan. Initially outraged at the switch of teachers, Stephen learns, under Mashkan’s tutelage, to breathe like a singer and to croak out a melodic line. A previously self-absorbed soloist, he discovers the wonderful and subtle give-and-take between singer and accompanist. And as he works through each song in Robert Schumann’s wonderful cycle Dichterliebe ( " Poet’s Love " ), he begins to melt the emotional dam that has been blocking his performance. His encounters with Professor Mashkan in a cluttered Secession-style atelier are as much life lessons as they are musical instruction. The arrogant young Californian finds that the threadbare, Old World, psychologically fragile pedagogue has much to teach him.

The premise of the bratty know-it-all youngster learning, albeit reluctantly, from the crusty old master is of course a literary and dramatic cliché (The Karate Kid, Tuesdays with Morrie), but Marans imbues the theme with originality and freshness. He also sets his story in a context — the study and performance of classical music — that may be about as arcane and formidable as that of quantum mechanics in Michael Frayn’s Copenhagen. What’s more, he doesn’t water down the musical material but exploits its metaphorical possibilities with considerable elegance and eloquence. An especially gratifying touch is the use of recorded excerpts from Dichterliebe between changes of scene.

As imagined by Marans and embodied by Mark Boyett, Stephen is initially more obnoxious, more the churlish Yank, than is entirely plausible. A former prodigy who can do devastating imitations of Alfred Brendel, Glenn Gould, and Vladimir Horowitz, he confesses that he has technique to burn. What he lacks is warmth of expression — as demonstrated in his first, metronomic run-through of the piano part in the opening Dichterliebe song. It’s a little hard to believe that such a promising performer would be so utterly without musical feeling. Tensely wound, beset with nervous tics, full of sexual anxiety, Stephen is also a Jew who does his best to hide his heritage. But then he goes to the opera and falls in love with Pagliacci. He takes a trip to Dachau and meets a simpático Jewish woman while touring the outrageously prettified camp. The dam bursts. Suddenly furious at all things German, he refuses to speak (or sing) in German and takes to wearing a yarmulke. He barely tolerates Professor Mashkan, who he believes is an anti-Semite.

As played by David Rogers, however, Mashkan is a constant revelation to us and to Stephen. Desperate to hold onto his only student, the professor meets Stephen’s boorish behavior with tough love. He punctures Stephen’s defenses and points out his secret weaknesses. He pokes fun at the yarmulke, calling it " your look-I’m-Jewish hat, " and offers an alternative example of Jewish dignity. He demonstrates in music the simultaneity of sadness and joy, and how the presence of one emotion heightens the other. And when he finally reveals his own Holocaust story, he does so reluctantly and in a whisper that can’t be heard by the audience. As he says, " You have heard the words before. Everyone has. They have become so commonplace. " What he recommends to Stephen is the advice in Schumann’s final song, from which the play takes its name: " Let us bury the old wicked songs/The dreams so evil and bad,/let us bury them now —/fetch an enormous coffin. . . . I want to sink my love and my sorrow in it. "

Both Boyett and Rogers have played their roles in previous productions, so their interaction is spontaneous and natural. They are particularly effective in miming piano performance. Seated at a shawl-draped grand piano, with its keyboard facing the back wall, the characters in turn hunch myopically over the music rack, stumble or rush through the Schumann accompaniments, show off with bits of Beethoven and Liszt and Bach. They’re so good, you can’t tell that they are operating a built-in player-piano synthesizer. Old Wicked Songs may treat subjects and themes that are familiar, but it does so with almost perfect pitch and few splintered notes.