The email blast from the head of my son and daughter’s theater group relayed a frantic plea: “We need to raise $16,000 before the upcoming spring performances,” Anya Wallach, the executive director of Random Farms Kids’ Theater, in Westchester, New York, wrote in late May. If the money didn’t materialize in time, she warned, there could be a serious problem with the shows: nobody would hear the actors.

Random Farms, and tens of thousands of other theater companies, schools, churches, broadcasters, and myriad other interests across the country, need to buy new wireless microphones. The majority of professional wireless audio gear in America is about to become obsolete, and illegal to operate. The story of how we got to this strange point involves politics, business, science, and, of course, money.

Four years ago, in an effort to bolster the country’s tech infrastructure, the FCC decreed that the portion of the radio spectrum used by most wireless mics would be better utilized for faster and more robust mobile broadband service. Now, as the telecom companies that won the rights to that spectrum begin to use it, the prior tenants are scrambling for new radio-frequency homes.

The dispossessed are a diverse and varied lot. Wireless mics are near ubiquitous in modern life, in our schools---think lecture halls and pep rallies---our offices, our hotels and meeting halls, our entertainment venues, musical and theatrical tours, our houses of worship, and our radio and television broadcasts.

Replacing them will not be cheap. Even small community or school theaters can use 30 or more microphones, which, including ancillary gear, can cost $1,000 or more apiece. “I’ll need to replace at least 24 mics, which will cost at least 24 grand,” says Brian Johnson, artistic director of the theater program at La Habra High School, in California. The Shakespeare Theatre Company, in Washington, DC, will spend $50,000 on new mics, says Tom Haygood, their director of production.

Behind the scenes, the stagehands responsible for moving sets, rigs, curtains, and the like also use wireless communications devices. Nearly every director I spoke with said that regardless of their theater’s financial condition, they’re immediately replacing this gear out of safety concerns. Shakespeare Theatre Company’s Haygood says he’s already spent another $45,000 on headsets for backstage personnel. The combined expense will hamper many companies’ ability to pay for musicians, costumes, and sets. “Basically, we will be robbing Peter to pay Paul,” one director told me. By the time the switchover is supposed to be complete, in July 2020, the total tab could top $100 million.

For commercial broadcasters, and other corporate users, replacing wireless gear won’t be a financial strain. But it’s a pending crisis for nonprofit theaters, which generally rely on ticket sales and donations to survive. Many school theater programs will have to appeal to their community, as their districts don’t often fund such a capital expense. “The idea of going to a school board and asking for money to replace audio equipment is a non-starter,” says Jim Palmarini, of the Educational Theatre Association, a national organization of school theater programs. He says half of the group’s members rely solely on box-office revenue. Most community theaters don’t have any hope of municipal help, and as nonprofits few of them have the resources to easily cover such a large outlay. That’s why, Wallach told me, she sent her panicked email asking for funds.

Wireless audio, like all wireless communication, operates by sending and receiving signals on specific frequencies in the radio spectrum. Each part of the RF spectrum has different characteristics, better suited for particular uses. The low-end waves, such as AM radio, are very weak, but can travel many miles. On the high end, home to x-rays, waves are intensely powerful but don’t travel far. It’s the juicy part in the middle that’s so desirable for communications devices, making claims for every frequency in that range competitive.