The two Tzadik albums, bracing yet sumptuous, remain the ideal place to start with her work. But they do not offer a tidy summation of Amacher’s achievements. The musicologist and violist Amy Cimini, a member of Supreme Connections, said that listeners could hear “Sound Characters” and think they had Amacher pegged. “They’re like: ‘O.K., I totally get what this music is about — it’s about this crazy inner-ear sensation, she understood that intuitively, end of story,’” Ms. Cimini said. “And that’s not the story, actually.”

When she died, Amacher left a wealth of material that was unfamiliar even to close associates: theoretical writings, a deep tape library of the tones she mixed during installations and some notated material. Excitement was tempered by caution and an understanding that Amacher’s presence had always been central to presentations of her music. Now others would have to take up the task of producing her desired effects. Hovering is an uncomfortable question: Can her work be revived with any hope of success?

At the premiere of the luminously morose “Petra” in 1991, Amacher and Marianne Schroeder played the pianos, without a formalized score. After Amacher’s death, archivists discovered voluminous notes for the work, including revised sketches. In New York on May 24, Ms. Schroeder will play the piece again, this time with Stefan Tcherepnin, a former student of Amacher’s. Mr. Tcherepnin said that he and Ms. Schroeder plan to linger in the concert space in the days before the concert, testing out resonances and picking out parts of the various “Petra” sketches that sound particularly exciting inside St. Peter’s. Given the site-specific nature of Amacher’s own approach to performance, this seems as promising as any method that might be used to channel her aesthetic.

Yet not all of her past associates are persuaded. The composer and pianist Frederic Rzewski, who played with Amacher in MEV, wrote in an email that “the best thing would be to make available those parts of Maryanne’s work that do exist and are indisputably serious works of art.” But describing “Petra” as an official opus in her catalog, he wrote, makes him uneasy. Noting the absence of a two-piano score, he likens the piece to an improvisation and counts himself skeptical of attempts to mount it without her.