Acoustics are to a sound designer what playing space is to a director: both context and canvas for their artistic work on a show. Just as physical parameters constrain staging, not to mention scenic and lighting design, the acoustic properties of a room shape a sound designer’s choices, both creative and practical.
But unlike theatre floor plans or lighting rigs, the aural properties of a space are difficult to specify and accurately describe on paper. Acoustics, or how sound responds to a particular space, can be determined by science but are often best judged by subjective emotion. A designer may flag certain challenges and limitations indicated by a theatre’s layout, though the overall feeling inspired by sound moving through space can only be experienced fully in the room.
Indeed, while much of a design team’s focus will tend toward the physical properties of the playing space—mapping its sightlines, lighting its surfaces—sound design is uniquely attentive to the entirety of a space, or at least what’s considered its acoustic volume. For example, fly space above the stage means rigs and storage for a scenic designer, and likely not much for a lighting designer, since the area can’t be seen. But a sound designer must contend with any space where sound can travel, and what happens when it gets there—including the ceiling, walls, floor, and even audience members.
Acoustic concerns in theatre can be considered as a sort of nesting-doll equation. Think of the outermost layer as the theatre space itself, the fixed architecture of the walls, seating plan, stage configuration, and the materials used throughout. Then there is the inner architecture of a show, its scenic design, use of the space, and the particular needs of creating a world that sounds a certain way. How these two levels interact and function well together, to deliver the kind of intimate or reverberant soundscape that can make or break the imaginative contract between a show and its audience, is a sound designer’s primary concern.
What makes a “good” acoustic space?
For the purpose of picturing something as ineffable as acoustics, metaphors can be helpful.
“Think of dropping a stone into a pond, and you can see a set of waves moving out from there,” says Charles Coes, a sound designer and engineer with a wide range of production experience, including on Broadway. As soon as that sound hits any surface, it will bounce off of it and become what’s called a reflection. “If you’re sitting halfway between the sound source and the wall, then you’ll hear my voice arrive first directly to you. And then some period of time later, you’ll hear the bounce off of that wall,” Coes explains. The direction and quality of such reflections shape the acoustic dynamics of a space.
An optimal reflective surface sends sound in multiple directions at once, Coes explains, creating what are called diffuse reflections. “Diffuse reflections are great because our brains don’t do a good job of saying, ‘Oh, that sound is coming from over there’ when sound approaches us from a variety of angles,” Coes says. “Diffuse reflections keep the acoustic energy in a room up; we can hear a little better, we hear a little louder, but we’re still able to see and hear the sound coming from an actor.” More challenging reflections, like the cold bounce off a glass wall or the tinny echo from a hard metal, may require mitigating strategies, like soft fabrics or other materials positioned to absorb reflections before they become disruptive.
Some best practices and specifications to control reflections have become common in theatre construction, such as a slight angling of exterior side walls to avoid sound bouncing back and forth between parallel surfaces as in a game of ping-pong. Most Broadway houses have good acoustics for the human voice, Coes explains, because of diffuse reflections created by plasterwork surfaces, the theatres’ slight fan shape, and audience proximity to the stage. But every theatre is different, and of course not all of them began their lives as performance spaces.
There are multinational consulting agencies devoted to just these sorts of considerations, whether optimizing new constructions from the ground up, renovating existing houses, or creating new performance spaces inside existing structures. One such company, Charcoalblue, takes the approach of crafting spaces “by theatre people for theatre people,” says John Owens, a New York partner in the London-based firm. In operation since 2004, Charcoalblue works with theatre companies to create or adjust existing spaces to match their artistic ambitions and practical means, with attention to everything from sightlines and acoustics to seating and versatility.
Three primary considerations factor into their work on optimizing theatres for sound, according to Byron Harrison, who joined the company in 2010 and heads up its acoustics team. “First off is making sure that the seat count is appropriate for the artistic ambition,” Harrison says, a process he calls “right-sizing the room.” By this he means balancing the scale of what a theatre wants to achieve artistically with the intimacy required for audiences to hear actors directly. The second is minimizing the acoustic volume of the theatre, ensuring there’s no excess space where sound can get lost or reflect back with such delay that it creates an echo.
A recent example of both these challenges is the company’s work on Southern Rep Theatre’s new home inside the former St. Rose de Lima Church in New Orleans. By constructing a black-box space within the grand outer structure, the team was able both to create a close-knit space and to solve the acoustic problem of a lofty vaulted ceiling.
The third consideration is audience arrangement around the stage. Ensuring that actors can be heard no matter which direction they’re facing is particularly tricky for spaces set in the round or in thrust configurations. Such cases often require reflective surfaces positioned to direct sound back out to the audience regardless of which way an actor is turned. Coes also greatly credits actors for controlling the diction and direction of their own voices. “We have collaborators in every actor and every musician in terms of what they’re doing and how they can help us,” Coes says. “The human voice is directional; it is to some degree like a flashlight.” Whether cheating a few degrees or angling their heads toward the balcony, “actors have an immense amount of control over how they interact with the acoustics of the space.”
To mic or not to mic?
There is a sort of Platonic ideal that companies like Charcoalblue strive to create, of theatre spaces whose acoustics function naturally without the need for technological reinforcement. “There are those among us who have lived with microphones and speakers for a very long time, who know the tricks in order to move things around in an electro-acoustic fashion,” Owens says. But working to craft an acoustically ideal space through “true room form and design and volume is really quite interesting and special,” he says almost philosophically. Very few theatres with more than 1,000 seats can work well acoustically unassisted by mics, Harrison adds, citing London’s Old Vic as a rare exception.
But the needs for a production using microphones can be quite different than those that operate unassisted. “There’s a giant difference between a show which is reinforced, where you are trying to replace the acoustics of the room,” Coes says, and a show that may be “lightly reinforced” but still relies on a series of helpful reflections in the room to carry actors’ voices naturally. “What we want are adjustable acoustics, which are not necessarily easily done,” the designer says. For Charcoalblue, the balance lies in building a certain amount of versatility into the space, but not so much that it would rarely be used.
Charcoalblue seeks designers’ input on how they interact with a particular space, including the placement and integration of sound systems. “There is a different signature to sound designers’ equipment, which are their tools of the trade to paint the audio pictures that they require,” Owens says. Conversations about how sound equipment fits into the architecture is one of the most important considerations pre-design, Owens says.
The show’s the thing
The first question for any designer is how naturally a show fits into the performance space. “If you’re doing a small, intimate drama in a tiny black box, the acoustics are going to serve you very well,” Coes says. Jane Shaw, a sound designer with more than two decades of experience in theatre and dance, offers another example. “A musical in a huge warehouse—that’s a big challenge,” she says. “If it’s not an acoustically great space, the question is what kind of system can deliver the clearest sound possible without contributing to the noise in the space.” That may often include a combination of finding the right system of mics and speakers and integrating sound-absorbing materials offstage or even into the scenic design.
“Scenery typically leads the way in most productions,” Shaw says, adding that in early production meetings, sound designers may mention speaker placement and other acoustic concerns for the team to keep in mind down the line (though they won’t always be heard). Some such issues may be easy to anticipate, like footfalls on a hollow floor or echoes off parallel walls, but most others come down to troubleshooting and creative solutions during tech.
“I will always spec sound-deadening materials in every floor, for lots of reasons, but one of them is for the benefit of the sound designer,” says Rachel Hauck, a scenic designer currently represented on Broadway by Hadestown and What the Constitution Means to Me. “Sound is not the driving reason to make any scenic choice, but it’s a factor in making final finishes,” she says.
Finessing the way a set sounds or behaves acoustically becomes an interdisciplinary effort. Says Coes, “Very often it’s a conversation between a scenic designer, technical director, a props artisan, and a sound designer about, these are the things that might make this door sound a little bit less hollow, a little bit beefier, or we have to make sure that this wall built of flats doesn’t move as we slam the door.” The process comes down to making sure everyone’s on the same page about what sounds are expected to occur live, and then auditioning a number of approaches.
In the case of an onstage band, the acoustic properties of a set become everyone’s concern from the get-go. “With Hadestown, there were extensive, 5-bajillion-email chains about how to contain the sound of the drummer, in particular,” Hauck says. Minimizing bleed between band mics, balancing instrument levels, and accommodating vocals are shared concerns that involve both sound technologies and physically containing sound within a space. This kind of work is common for sound designers in conventional orchestra pits, where there’s less reason for such design collaboration because the area can’t be seen by the audience.
Because the band is visible in Hadestown, though, the need to isolate the drums wound up shaping the look of the show. The drummer is situated in a booth that’s lit through perforated tiles above, whose interior the team carefully optimized for sound using various fabrics and foam. Set underneath a second-story balcony, the booth also needed to be fronted by a barrier of 24 inches to prevent sound from the drums booming directly onto the stage. That barrier then became a bar where the show’s trio of Fates hang out when they’re not out front singing. “It’s all a wonderful hybrid,” Hauck says. “Because it’s a perfect place for them—they are watching over everybody front and center.”
Some productions may proactively consult a firm like Charcoalblue about scenic acoustics, as producers did on the current Broadway revival of Oklahoma!, which is performed three-quarters in the round at Circle in the Square. More often, though, the consultation comes due to a catastrophic-seeming glitch in the final hour. The Young Vic’s 2017 production of Life of Galileo, for example, featured a dome-shaped surface suspended above the stage on which stars were projected. The acoustics of the design hadn’t been considered until after it had been hoisted in the air. “They realized that they had created something that was very, very bad,” Harrison says. “The focal length of this curve and the height that it was was kind of uncannily wrong, and trapping sound within the stage area.”
The team at Charcoalblue entered the dome’s dimensions into a computer model, trying to solve a puzzle Galileo himself might enjoy. In the end the solution was simple: Reflections needed to be diffused when they hit the floor. Fortunately the production was already planning to seat audience members on bean bags gazing up, which would accomplish just that.
“Sometimes it’s just being able to say, ‘This is going to be fine on the day,’” Harrison says. “You could modify your scenic design and solve this problem—or you can roll with it,” knowing that sometimes just having an audience makes all the difference. Like any other element of live theatre, acoustics come down to an alchemy that can seem like magic to the audience, no matter how much unseen maneuvering goes on behind the curtain.
Naveen Kumar is a New York City-based writer and editor who covers culture and entertainment for outlets including them.us, InStyle, VICE, The New York Times, The Daily Beast, and Towleroad, where he serves as theatre critic.
CORRECTION: An earlier version of this story stated that the current Broadway staging of Oklahoma! is presented without microphone reinforcement; the cast and musicians are reinforced throughout the performance.