When a new production of Monteverdi’s “L’Orfeo” premieres at Santa Fe Opera on July 29, something about it might seem slightly odd.Sure, there will be the usual Orfeo, in this case the tenor Rolando Villazón, and a familiar sight at the podium in the conductor Harry Bicket. If the staging by Yuval Sharon, one of the most creative opera directors at work today, provokes a thought or two — well, that is only to be expected by now.No, what might surprise people most is the sound emerging from the orchestra pit. This will not be Monteverdi as we have heard him; there will be nary a period instrument in sight, neither a harpsichord nor a sackbut, a theorbo nor a cornett. It will be, rather, Monteverdi as newly orchestrated by Nico Muhly and brought right into the contemporary.“It’s a piece of music I’ve always loved, and I love Monteverdi,” said Muhly, a composer whose opera credits include “Marnie” and “Two Boys.” Accepting the Santa Fe commission, to him, “seemed like a really easy ‘yes.’”Santa Fe’s production, titled “Orfeo,” is not intended as a grand revanchist blow against the period-instrument movement that has claimed early music as its own for decades. Bicket, after all, is the music director of the English Concert, once in the vanguard of that movement and still one of its eminent groups. And Muhly was offered the assignment because his love for Byrd, Tallis and the like is not just avowed, but audibly present in much of his own music.Yuval Sharon, left, the director of Santa Fe’s “Orfeo,” and Muhly.Brad Trone for The New York TimesWhat Santa Fe’s “Orfeo” does speak to, though, are the artistic opportunities that are starting to open up as the first generation of period-instrument pioneers pass from the scene, the early-music movement confronts an uncertain future and all the old polemics about how works ought to be performed start to seem passé.At any rate, doing “Orfeo” in the way that Nikolaus Harnoncourt, John Eliot Gardiner and Jordi Savall have would be impossible at Santa Fe. The company has a resident orchestra that uses modern instruments, and even if period instruments could be brought to the desert for the summer, “the size of the building,” Bicket said, “means we would probably have to have, like, five theorbos and three harps and all these harpsichords, which in an open-air theater is not really practical.”Typical repertory companies, too, aren’t able to present the work as it has come to be heard — which is not just a shame, but also a detriment to our collective understanding of opera itself.“It’s not appropriate to call it the first opera, because we know it was not the first opera,” Sharon said of “Orfeo.” “Opera was not a genre at this point, when this piece was created. But in many respects, I think it makes perfect sense to call it the first opera, because it set the benchmark for what we look to opera to create for us.”This orchestration, Muhly explained, therefore aims to make the work more practical to perform in standard houses, beyond Santa Fe. “I’m not doing anything crazy to it,” he said. “It’s just about it not being this unwieldy thing.”COMPOSERS HAVE LONG been interested in reorchestrating “Orfeo” for contemporary ears; in its treatment of the Orpheus myth, it is, fundamentally, an opera about the power of music.Sharon said of “Orfeo” that “it set the benchmark for what we look to opera to create for us.”Brad Trone for The New York TimesThe conductor Henry Bicket, who said that in preparing this new production, “We agreed that it would be Monteverdi’s ‘Orfeo.’”Brad Trone for The New York TimesThe work, with a libretto by Alessandro Striggio, premiered in 1607. But, according to the musicologist Nigel Fortune, it was largely forgotten after Monteverdi’s death, in 1643, until the late 19th century. Then, Vincent d’Indy, Carl Orff, Ottorino Respighi and Bruno Maderna all tried their hand at a reorchestration. For the Maggio Musicale in Florence in 1984, Luciano Berio convened a quintet of young composers — Betty Olivero and Luca Francesconi among them — to rewrite “Orfeo,” employing electronic tapes and even a rock band. By then, however, the period-instrument revolution was in full flow; when Paul Hindemith presented a scholarly “attempt to reconstruct the premiere” in Vienna in 1954, Harnoncourt and other members of his recently formed Concentus Musicus Wien played in the ensemble.To Bicket, none of those versions, or others, seemed appropriate for use at Santa Fe; they involved cuts, or were too of their own time. But since Santa Fe has had a tradition of presenting a premiere each year, he explained, a new production seemed an ideal opportunity to commission “a young, contemporary composer to say what this century has to say about this music.”And Muhly is an admirer of “Orfeo.” “There are so many moments of slyness, where what you’re getting in terms of plot and what you’re getting in terms of emotional content is coming from literally one tiny little harmonic move, like one strange flat,” he said. “Also, there’s very traditional word painting. You go up to heaven, and he goes up the scale. It’s this wonderful combination of trickery and things that are quite obvious and theatrical.”A rendering of Sharon’s production for Santa Fe.Matthew Johnson & Alex Schweder, visual environment designersOne of the reasons that so many composers have felt able to try their hand at orchestrating or adapting “Orfeo” is that Monteverdi left them the opportunity. Even the most conscientious, scholarly performer of “Orfeo” has to make choices about how to play it, because scores that were published early in the 17th century omit crucial details, especially in the continuo parts that comprise so much of the work.“All of it is a sketch, because there was no international music scene,” Bicket said. “Composers did not have to write information into the score, apart from a vocal line and a bass line and maybe a bit of harmony here or there, because there was an understanding, a style, which was part of being a musician in those days.”“When I do this with my own players in the English Concert,” Bicket added, “we do read the notes, but we are actually reading the rhetoric — and the heart of it is finding the rhetorical gesture.”Many of the conductors who have performed or recorded “Orfeo” have chosen to create their own editions; listen to some of the historically informed recordings of the work, Muhly pointed out, and you can hear divergences far more marked than in period accounts of, say, Beethoven symphonies, sometimes on matters as fundamental as cadences.Bicket leading a rehearsal of “Orfeo.”Brad Trone for The New York TimesThere is therefore no one, true “Orfeo” that anybody can be faithful to, and that invites creativity. For Sharon, a production of it can sit easily within his interest in how operas from the past can be recreated today. It’s an urge that — beyond his lauded work with the Detroit Opera and the Industry, the company he founded in Los Angeles — has seen him stage parts of “Götterdämmerung” as a drive-through and led him to present the four acts of “La Bohème” in reverse.“We’re all making a guess as to what it must have been like to have done this piece,” Sharon said of the Monteverdi. “We have to interpret it; we have to decide. What instruments are going to play this? What is the proper performance style for this? There’s no such thing, there’s just the humans that are bringing it to life at that particular moment in time, needing to take this blueprint that Monteverdi and Striggio left us and interpret it in our own way, and for our own time. So I think that makes it eternally an opportunity for constant reimagination.”Even so, Muhly asked for, and Bicket laid down, some ground rules. “We agreed that it would be Monteverdi’s ‘Orfeo,’” Bicket said, and it was stipulated that the vocal and the bass lines should remain unchanged from the primary source. Bicket wrote out a vocal score, filling in the harmonies that Monteverdi left out, noting where chords could be restated or shift in other ways.Otherwise, though, Muhly was left to translate the material into his own compositional language, which he had come to in dialogue with early music and even early instruments; among his published scores is a “Berceuse With Seven Variations” for solo theorbo.“I think because music of the past features so heavily in my own, original music,” he said, “I stepped to this with a form of irreverent veneration.”Muhly described Monteverdi’s score as “this wonderful combination of trickery and things that are quite obvious and theatrical.”Brad Trone for The New York TimesThat’s not to say the process was easy. While it was in some ways simpler than writing another opera of his own, Muhly said, in others it was harder, requiring him to innovate and defer at the same time. He has adapted the continuo part mostly for a small ensemble of alto flute, English horn, clarinet, bass clarinet and harp, and voiced the figured bass in octaves far higher and lower than tradition would suggest. Some of the trickier problems involved echoing the way in which Monteverdi shrinks and expands his orchestration, and making the underworld distinct, yet not “cartoonishly evil.”But what Muhly argues against, and confesses to being “a little bristly about,” is the perception that “a new take or a new interpretation of something in some way erases, or is in conflict, with the previous interpretation.” His version of “Orfeo” is not intended to supplant those that have come before it, still less to render early-music takes on the material redundant. Far from it.“You know what would be great, literally what would be fantastic?” Muhly said. “Let’s just say someone saw this thing and was like, ‘Wow, I’m totally fascinated by this piece,’ goes back and gets any of the period recordings, and it’s a gateway drug that way. Similarly, if someone hears it and is like, ‘I hated that so much, I really want to hear the original again,’ and then they go to the original again, that’s also good. I think that’s just fine.”The more Monteverdi, in the view of Muhly and his collaborators, the better.“It’s really not about me; it’s about you having a great night at the theater,” Muhly said. “I want the music to serve the drama. And that’s always how it should be.” More