To stop microbe-carrying droplets from spreading in an orchestra, turn the seating arrangement inside out. According to research published on June 23 in the journal Science Advances, orchestras should move percussion to center stage, move clarinets and trombones to the back, and most importantly, put the trumpets in the corners.
The symphonic shake-up puts the most aerosol-emitting instruments closest to ventilation systems and open doors. A computer model of airflow in the Utah Symphony’s concert hall showed that this strategy limits droplet spread better than six-foot social distancing. The new seating arrangement ensures that droplets are swept away without passing through other people’s personal space.
“You want the smoker to sit close to the window,” says University of Utah chemical engineer Tony Saad, a co-author of the new study, to Emily Anthes at the New York Times. “That’s exactly what we did here.”
The researchers began working with the Utah Symphony last summer as the group began looking for ways to return to their work safely. Normally, musicians in an orchestra sit within a few feet of their neighbors, in a pattern that is about a century old.
“Musicians in an orchestral band are very sensitive to their positions with respect to others in the band,” says Jiarong Hong, a mechanical engineer at the University of Minnesota who was not involved in the study, to New Scientist’s Adam Vaughan. “For example, trumpet players are always seated in the back and they get used to watching and listening to bassoon and oboe players in order to coordinate their playing.”
While that helps musicians hear each other and stay together, it also places super-spreading wind instruments at the center of the action. While string and percussion players can wear masks, those in the brass and woodwind sections are “manufacturers of respiratory droplets,” says Saad to Betsy Ladyzhets at Science News.
The research team created a computer model to understand how air and the droplets suspended in it flow around two concert halls, Abravanel Hall and the Capitol Theatre in Salt Lake City, during a performance. They relied on previous research into the aerosols emitted by different instruments—trumpets release the most with 2,500 particles per liter, far beyond the second-highest emitter, the oboe, with just 400 particles per liter.
The model showed that while most of the air flowed from the vents in the ceiling to those in the floor, two vortices of particles also formed at the front and back of the stage.
Next, the team used the model to find a solution that minimized the particles.
“We asked them when we started the project, ‘What constraints do we have to work with? Can we move people?’” says University of Utah chemical engineer James Sutherland, who co-authored the research, to the New York Times. “And they said, ‘You do whatever you think you can to mitigate risk.’”
The new seating chart puts the highest-emitting instruments closest to vents, and the musicians who can wear masks while playing furthest from the vents. The change probably has more impact on the musicians and conductor than on the audience’s listening experience, Sutherland tells Science News.
Their model is like a worst-case scenario, says Saad to New Scientist. First, it assumes all of the musicians play simultaneously and continuously, and every musician produces the same amount of droplets as others playing the same instrument. The researchers also did not factor in the droplets made by singers, or the updraft that can be created by a crowd of warm bodies sitting under hot stage lights.
By simply changing the seating and opening doors and windows, performance spaces can reduce the probability of infection by a factor of 100.
“Simulating the flow inside an orchestra hall is not easy,” says Hong to the New York Times. “They did beautiful work in terms of characterizing flow.”
The Utah Symphony used the researchers’ recommendations during their spring performance season. But this fall, Brosvik tells the Times that the orchestra hopes to return to their usual seats.