There is an army behind every production of, say, “La Traviata”: armorers and fight directors for the action; lighting technicians giving Violetta’s last breaths a ghostly frisson; wig-makers and costumiers who make the Paris demimonde glitter. An even less visible figure, whose contribution and responsibility is huge, though you will seldom see them at the performance, is the repetiteur. Their job, conducted behind the closed doors of practice room and rehearsal studio, extends beyond a single scene or even opera. They play on the piano every note of what the season has in store, over and over.

Most of the time audiences won’t see or hear the repetiteur. They will appear in the program, if at all, under “musical preparation.” Still, there is perhaps no other single individual involved in the production of an opera who creates so many aspects of it. “What you and the conductor have that no one else does,” repetiteur Alice Turner tells me, “is that you play every single note. You do the damn whole lot.”

They also sing close to every single word. One repetiteur told me that he has learned every role in La Traviata. A standard expectation for the auditioning repetiteur is that they might play not just the fiendish accompaniment to the end of Act Two of Mozart’s “Figaro” but sing every single part in that huge ensemble; their language skills are, most often, second-to-none.

And repetiteurs make sure that pitch and text carry, project, glow. They listen, conductor John Andrews tells me, “with the ears of a vocal coach—breathing, support, line.” They can dig into details too small for group rehearsals; they can “cover what the conductor isn’t covering.” Andrews compares them to a “container” that can catch and store everything that happens in the rehearsal process: they are “listening as much as they are playing.”

When the production moves away from the piano and into the rehearsals with orchestra and in the theater, the repetiteur becomes the troubleshooter who finesses the music in the context of the drama, listening for grit in the acoustic oyster. They are often a vital go-between for the conductor and director, a place not always easy to occupy: Nick Fletcher, chief repetiteur at the Royal Danish Opera and formerly a Jette Parker Young Artist at The Royal Opera in London, told me of a rather farcical bust-up over the precise order in which Papageno’s onstage bells were struck, in “The Magic Flute.” One of the challenges repetiteurs face, Andrews tells me, is learning to mould themselves around the diverse talents in the room, and translating between the musical language of the score and the expressive languages of dancers, choreographers, and actors.

It’s work that is comprehensive, essential, but rarely visible. Elspeth Wilkes has worked with myriad London opera companies playing continuo, the semi-improvisatory accompaniment we find for instance in Handel and Mozart operas, usually on harpsichord or fortepiano, and one of the repetiteur’s occasional responsibilities. It’s a useful stand-in for the repetiteur’s job as a whole: they must be “under the surface,” present but unobtrusive. (Indeed, critics in London moaned about what they saw as an over-indulged fortepiano in the pit for a recent “Così fan Tutte”). It’s “like a tightrope walk,” Wilkes says, recalling a time when a singer skipped four pages of music with her scrambling ahead to catch up.

Paul Webster,  a repetiteur who has worked at Glyndebourne and the Opera National de Paris, tells me he doesn’t see himself as a pianist. It’s a rather counterintuitive thing to hear from someone who has spent thousands of professional hours at the keyboard. The discipline required to keep playing music to a high standard in the rehearsal process, with its eye-watering repetitions and mammoth sessions, is mind-boggling. He goes on to say instead that he is “a musician, and the piano is the tool of my trade.”

It’s a precise summation of the repetiteur’s temperament, manifested in a demure and unfussy efficiency, to downplay their obvious instrumental talents (something John Andrews finds is “genuinely annoying to those of us who really are bad pianists”). Anyone who has seen the piano reduction for the closing scene of “Die Walküre” will recognize the demands implied in its forest of black notes. Virtuosic works for solo piano are still required for repetiteurs auditioning to join the music staff at a major house (though their professional and artistic diet is often richer than that of the soloist, who must plug away at scales for hours on end).

For Nick Fletcher, there is something fundamentally different about how repetiteurs approach the sound they make on the piano. “The important thing is whether you play orchestrally or not,” he says. It’s about “using the piano to create sounds the singer is going to hear when they get with the orchestra.” The biggest stumbling block is in the nature of the instrument. “As a percussion instrument,” he says, “pianists have a tendency to play incredibly vertically, whereas an orchestra plays very horizontally.” Elspeth Wilkes tells me that one of the principal technical challenges is in the approach to fingering and hand positions, which work differently because of the orchestral sounds they are trying to summon. Repetiteurs are in the business of inventing a whole range of piano sonorities; in this respect they are hybrid musicians, innovators and improvisers, experimenting with sound and timbre, though with characteristic understatement.

Part of their artistry is the treatment of their musical raw material: piano reductions of an opera’s orchestral score. Wilkes calls some of them “unplayable” and “awful.” They are imperfect creatures, sometimes missing vital orchestral details for cueing singers, and sometimes failing to communicate the textures, colors, or moods the composer summons. Trying to play everything written can be a big mistake, Paul Webster tells me, one often made by pianists whose primary training or temperament is that of the soloist.

Repetiteurs see vocal scores as open-ended, and their art is in recomposing and reimagining them. They are, Webster says, “things of convenience, not fixed texts like a Chopin Mazurka.” Octaves may be added to imitate the density and richness of an orchestral string section; attacks might be sharpened to emulate the sound of the winds. Prominent instrumental lines that the reduction occludes might be brought back in. It can even go, Nick Fletcher tells me, as far as “rewriting a whole passage.” Alice Turner describes “a lot of time at the kitchen table with a pencil and tipp-ex—if you’re feeling particularly brutal.”

This reworking and revisiting of raw musical material speaks to those improvisatory traditions that have always been a part of classical music culture, even if professionalization and standardization have put them in abeyance. It’s the space where the line between performer and composer is properly blurred, and where musical works are constantly transformed in rehearsal and performance. There’s something gratifyingly messy and tough about the way repetiteurs encounter these scores: a reminder of the ragged and practical core of music-making, which the spectacle of performance and our ideas about great artists at work are at pains to smooth over.

All this requires preparation. Most repetiteurs will work through their piano score with a copy of the full orchestral score and use it to provide a glossary for rehearsal. A director I spoke with told me that a repetiteur he knew had already begun preparing the score for a 2021 performance of Wagner’s “Tristan und Isolde.” Fletcher is also working on that mammoth opera at the moment. “I reckon I can get through 15 pages an hour of the vocal score,” he wrote in an email. At 320-odd pages in the Schott vocal score, this is over 21 hours work.

But that is only a fraction of the labor entailed. “Most theaters don’t give you time to learn this as part of your working week,” he writes, so “you have to practice before or after rehearsals or at the weekend…your career is limited by how quickly you can get these pieces into your system to coach and play.” The strain is enormous. Turner described the physical demands of two full piano runs of Britten’s “A Midsummer Night’s Dream.” Imagine the stamina required to embark on learning a new work straight after that.

I spoke to an internationally renowned soloist who spent his pre-breakout years as a repetiteur, who asked for anonymity in order to speak frankly. He was blunt in his assessment of the key attributes needed for the job: “the ability to deal with cunts.” Obsessed with opera from his early teens, voraciously consuming scores and libretti, he was certain that being a repetiteur was a natural fit. His love of opera was, he put it, “benignly bereft of any concern with the actual industry itself.” Disillusionment promptly followed.

In the United States, the singers he worked with only seemed to care about the voice, and were “fundamentally disinterested in the libretto and the drama.” He was quickly disabused of the notion that opera might be an art form offering “any form of intellectual solace.” It killed his love of opera, he told me, for years. The work felt dehumanizing because singers are “only nice to you when they need you”; feeling like a “middle cog in the hallways of power” was bruising and frustrating.

Paul Webster spoke of his work and colleagues with great fondness, but also observed some of the challenges of working in the environment of the opera house. He was most comfortable, he told me, working with singers in small spaces: coaching them in relative seclusion. But the rehearsal studio is a much more crowded place, with the personalities of singers, directors, conductors all whirling together. There, he tells me, “the personae become much bigger and theatrical…I found that a bit difficult to deal with.”

But the soloist’s time as a repetiteur was much more than an unfortunate detour or glitch. “The bitch work of being a repetiteur was extremely valuable,” he said, even if its relentlessness taught him, in his twenties, “the jadedness of an older musician.” He learned to work “ungodly hours”—a grim necessity for most musicians—but also to keep diverse repertoire in his head at the same time.

The unique synthesis of text and music opera manifests shaped his musical psyche, in the end. “I imagine text when I’m playing instrumental music,” he tells me. “I am who I am today because I was a repetiteur.”

The temperament of the repetiteur is perhaps one of the most unusual in the music business. They are rehearsing rather than performing musicians. And although they may find themselves in the pit from time to time, they are unlike the main cast or indeed lead figures in the production team who get their curtain call.

There is something public-spirited and quietly generous in the attitudes of the repetiteurs I speak to. They mostly love their work without equivocation, and none I talk to confess a desire to break out into the role of grand maestro, though many conductors do find their way to stardom that way: Antonio Pappano and Christian Thielemann began by playing the piano for Daniel Barenboim on his legendary Bayreuth “Ring.”

There’s a certain inwardness, even restraint, in the way the musicians I interview talk about their work. Repetiteurs have to maintain a stillness and Zen-like discipline in a charged atmosphere. By necessity opera singers manifest huge sounds and characters, which jostle for position with the director’s ideas and conductor’s musical priorities. The repetiteur must be the still point of this rapidly turning world.

I suggest to Alice Turner that this hidden state must be a source of frustration. Her musician colleagues do wonder, she says, how she could enjoy it when she never gets to take a bow. But performing in the pit is her least favorite part of her job. Rehearsing is where the action is, with its intense discussion of musical and textual detail. She is always keen “to crack on with a new show” and get back to coaching. Turner compares the role to being a civil servant. “You’re not the prime minister, but who cares?” she says. “You have to love the score and the words in front of you more than your own need to express or interpret.” ¶