The ad might have looked something like this:

Cast wanted: to bring to life three epic pieces of music, rarely performed; music requires epic forces—full complement of vocal soloists, huge chorus, giant orchestra plus massive percussion ensemble; recounts epic Greek drama, from the murder of Agamemnon by his wife Clytemnestra to the exoneration of their son, Orestes, for her murder. Sung in French. Sounds like a job for a good—no, make that great—school of music.

It was the University of Michigan School of Music, Theatre & Dance that took on the job—resurrecting Milhaud’s “Oresteia of Aeschylus”—and Thursday evening at Hill Auditorium a cast of more than 400, students and professionals both, conducted by the U-M’s Kenneth Kiesler, crowded the stage for a three-hour, I-can’t-believe-they-did-the-whole-thing performance of a score that even those who know it well—and they are few—call challenging.

The performance was a rare and perhaps sole instance of the three works—“L’Agamemenon,” “Les Choephores” and “Les Eumenides,” written between 1913 and 1923 and setting Aeschylus translations by Paul Claudel—being done at the same time.

The concert, a co-production with the University Musical Society, was being recorded live by Naxos for release on CD. So the work for the soloists, choristers and instrumentalists (these include three choirs from the U-M; the UMS Choral Union; the U-M Symphony Orchestra; and the U-M Percussion Ensemble) continues Friday and Saturday as final touch-ups are made. Jerry Blackstone and Eugene Rogers prepared the choruses.

I can’t wait for the recording: I have a suspicion that for once, the movie, so to speak, may be better than the play. There was so much to admire about the live performance Thursday, from the massiveness (and gutsiness) of the endeavor itself to the extraordinary playing by the orchestra and percussionists and fine work from the soloists; from Kiesler’s unerring command of Milhaud’s ever-thickening layering of rhythms, melodies and meters to the choruses’ assured embodiment of everyone from Furies to the people of Athens. And there is orchestral color of great appeal throughout.

But, yes, it is challenging music, especially on first hearing, and it does go on. Maybe a third of patrons seated in the orchestra thought it was challenging enough that they left at intermission, which fell after the first two sections. And the presentation, perhaps because it was geared to recording, may have exacerbated the challenges.

The soloists—Lori Phillips as Clytemnestra and her ghost; Dan Kempson as Orestes; Sidney Outlaw as Apollo; Sophie Delphis as Speaker and Leader of the Slave Women; Brenda Rae as a Slave Woman and, with Tamara Mumford and Jennifer Lane as Athena; Kristin Eder as Electra; and Julianna Di Giacomo as the oracle Pythia—were excellent. But they were buried just in front of the chorus or embedded in the orchestra rather than at the front of the stage. One result—which mikes and mixing will certainly fix in a recording—was that it was very often hard to hear them over the orchestra or distinguish their words. That’s not so good in a drama. Nor did their placement facilitate dramatic interaction—either with each other or with the audience.

Rather, a fine singer like Outlaw, off to the far right in the orchestra, had to keep stealing glances at Kiesler for his entrances; and yet, many of his interactions were with the Athenas (a trio that sings together to shimmering effect) upstage of him in the center—but he can’t really sing to them there.

Even the marvelous Delphis, to whom fall Milhaud’s rhythmically intoned speech settings of Claudel’s text, was a little hard to hear. She was magnificent—declaiming in the manner of a classical French actor in a drama by Racine—but how much more could we have gotten were she not at the back of the stage, but up front and communicating more directly?

There are so many words in the three hours of the three works—there’s very little repetition in the way of words—and with a writer like Claudel as partner, one has to assume they were important. But the choruses’ words, like those of the soloists, often seemed obscured by the orchestra. That, too, may disappear in the recording; it’s also possible the balances on stage may have been calibrated to work out in a recording.

It’s also true that the chorus has lots of wordless singing and speech-in-rhythm—very effective and quite extraordinary dramatically. But many times during the evening, the only way of following the narrative was to stare upward at the English supertitles. And Milhaud seems to reserve much of the emotional impact of the drama for the orchestral writing—the choral vocal melodic lines don’t tell us nearly as much. And sometimes the chorus seems just another instrumental color, though an important one. Still, together that meant an experience that was a little like hearing a tone poem and reading what the music tells us abstractly. So all told, much of the time Aeschylus’s drama of blood revenge felt rather bloodless.

Still, it was great to experience the work, whose powerful points go from beginning to end: Philips first piercing entrance as Clytemnestra, as alarming as the murder she’s just committed; Delphis’s final questioning “Ou, Ou, Ou” (Where? Where? Where?”) in “Les Choephores; the conversion of the Furies to the Eumenides by Athena. That goddess, times three, is a persuader of the first order, and Milhaud stages the scene, the climax of “The Eumenides,” in waves of refusal each fiercer than the last before the Furies submit to Athena’s will. It’s a psychologically astute and operatically choreographed finale.