I can still remember the first time I clipped a lavalier microphone on someone for a TV broadcast. It was during my internship at AT&T Corporate Television in 1978, back when razor blades were still used for editing and the smell of hot glue meant progress.

The mic was a Sony ECM-50, a small, rugged piece of engineering that quickly became my favorite. It needed a quirky little “N” battery that you could only find in specialty stores, but it sounded beautiful.

A few months later, I met what felt like pure science fiction: my first professional wireless microphone system. It was a Sony UHF transmitter and receiver paired with that same ECM-50 element, and for the first time, I could capture sound without being chained to a cable. The audio was clear, the signal was stable, and there were no wires to trip over. It just worked.

For a long time, wireless microphones felt like magic. Today, they feel more like triage. The magic has been replaced by management. Behind every concert, broadcast, or corporate event, there’s now a quiet war being fought over invisible real estate: radio spectrum.

The Shrinking Airwaves
Wireless microphones used to have plenty of room to breathe. For decades, most systems operated comfortably within the UHF television range from 470-806 MHz. These frequencies offered the perfect balance of power, antenna size, and propagation. But that was before governments realized the commercial value of those airwaves.

The first big hit came in 2009, when the transition to digital television freed up the 700 MHz band. The Federal Communications Commission auctioned that space to mobile broadband carriers like AT&T and Verizon, shrinking the number of open TV channels available for wireless microphone use. A few years later, it happened again with the 600 MHz band, much of which went to T-Mobile. Each time, the usable spectrum for professional microphones shrank.

While those auctions raised billions of dollars for the U.S. Treasury, none of that windfall ever found its way back to the professional audio community that once depended on those frequencies. Wireless microphone users—from broadcasters to theaters to houses of worship—lost access to critical portions of the spectrum without compensation or assistance to transition. The mobile carriers that won the auctions gained valuable assets, while production teams were left scrambling to replace equipment and redesign systems at their own expense. In effect, it was a one-sided trade: Culture and communication ceded ground so commerce could expand.

What had once been an open field is now a narrow alley. In most major cities, there may be only one or two available TV channels left for unlicensed wireless microphones. The rest belong to high-power mobile networks or other licensed users. As one engineer put it, “It’s like trying to park 50 trucks in a two-car garage.”

Problems and Solutions
I recently sat down with Mike Sinclair, a professional sound designer, to chat about problems and possible solutions. He's worked on everything from live events to concerts to corporate audio and described it bluntly: “You can plan every cue, map every signal path, and test every channel, but if you don’t have enough frequencies to manage the production there’s very little you can do.”

Even when you do find enough open frequencies, it doesn’t mean it will stay quiet. Modern environments are packed with devices that share or spill into the same spectrum. Multiple digital services are now actively competing for what is ultimately the same limited bandwidth.

The problem isn’t just about congestion; it’s about unpredictability. What used to be simple “set and forget” gear now requires active management. Sound engineers who once mixed audio now find themselves either running RF scans, plotting frequency tables, and negotiating for airspace—or spending a boatload of additional cash buying wireless systems that will do the investigating and hopping for you. Every production feels like a temporary truce with chaos.

The answer is often counterintuitive. You might think throwing more power and more money at the problem would make things easier, but in many cases, it doesn’t. As Sinclair told me, when multiple wireless systems have to coexist in tight spaces, very close together—like, for example, Broadway theaters—the solution is precision, not brute force. Engineers have to be surgical, using highly directional antennas and carefully tuned devices that keep their signals tightly contained to avoid interference.

Devices Fight Back
To survive in this new landscape, manufacturers have had to reinvent their technology. Early wireless microphones operated on fixed frequencies. Modern systems can tune across wide ranges, automatically scan for open spectrum, and adjust power output on the fly.

One possible approach could be treating each microphone as a separate radio signal, using one wide channel to transmit dozens of audio streams using time-division multiplexing. In simple terms, it sends tiny slices of each audio channel in rapid succession so that multiple mics can share a single piece of spectrum without stepping on each other. Sennheiser, one of the world’s leading innovators in professional wireless audio, has been at the forefront of developing new spectrum-efficient technologies, such as Wireless Multichannel Audio Systems (WMAS).

Joe Ciaudelli, the company’s director of spectrum and innovation, explained that WMAS technology "occupies a broader bandwidth but transmits multiple audio channels within that space using time-division multiplexing. This design dramatically increases spectral efficiency, enabling dozens of microphones to operate in a single TV channel.”

Solutions like this allow both microphones and in-ear monitors to operate in the same RF channel, dynamically allocating bandwidth based on priority. A lead performer can get full-fidelity, low-latency audio, while a backstage communication channel can tolerate higher latency and lower quality. For large productions, this means far more microphones can coexist peacefully in the same space.

For high-profile events, technology alone isn’t always enough. On-site professional frequency coordination can offer productions peace of mind by managing and accounting for each frequency.

Companies like Professional Wireless Systems (PWS) provide RF management and coordination for various events, including major productions like the Super Bowl Halftime Show. Jim Van Winkle, general manager at PWS, emphasizes that their competitive edge lies in on-site experience. He notes that an experienced RF coordinator is a "game-changer," bringing invaluable knowledge for pre-planning and crucial troubleshooting if issues arise.

For smaller or budget-limited productions, advanced technology safeguards can still help avoid chaos. One such approach uses wireless transmit/receive pairs that continually search for and stand by with clean backup channels. If interference or dropouts are detected on the main channel, the devices automatically switch to that backup while beginning a new search for the next available path.

Another company that has fully embraced the need for adaptability is Wisycom, a manufacturer long respected for its RF engineering in broadcast, live performance, and location sound. Its CEO, Davide Morsiani, said RF coordination has become "one of the biggest challenges in modern production—not because engineers lack skill, but because the spectrum itself is shrinking and unpredictable. Every location behaves differently, and even the same venue can change throughout the day. Our goal is to give users visibility and flexibility across the widest possible tuning range, so they can adapt instantly rather than rely on luck."

And one final approach that should be mentioned, despite its quixotic nature, would be for the FCC to actually begin policing the use of approved frequencies, as it's clear that everyone isn’t playing nicely in the sandbox.

Unified Voices
Technology alone isn’t enough. The professional audio industry has also learned that it needs a stronger and more unified voice in the policy arena. Shure led the formation of the Wireless Microphone Spectrum Alliance (WMSA), bringing together manufacturers, engineers, and end users to create a coordinated front at a time when spectrum access continues to shrink.

Shure has been deeply involved in the development of regulations in the United States and other countries, with spectral efficiency as the center point of its advocacy. According to Prakash Moorut, Shure’s global head of spectrum and regulatory affairs, WMSA now provides a platform for the industry to proactively educate policymakers about preserving wireless microphone access to spectrum, even as manufacturers innovate to use the remaining airwaves more efficiently.

The WMSA's work is already gaining traction. With more than 200 members, it has begun drawing attention in Washington at a critical moment, as the United States prepares to co-host the 2026 FIFA World Cup and later welcome the 2028 Los Angeles Olympics, two enormous global events that will rely on hundreds of wireless microphones for live performance, broadcast, and ceremony production.

Its outreach spans the White House, National Telecommunications and Information Administration (NTIA), FCC, and Congress, reinforcing how essential wireless microphones are to live performance, broadcast, cultural storytelling, religious services, and civic engagement. As Sinclair put it, “We can innovate all we want, but without spectrum, we’re just building better paperweights.”

Sinclair also floated an idea that goes beyond better microphones and smarter antennas—fixing the imbalance at its source. Many parts of the radio spectrum are still occupied by legacy government systems that haven’t been modernized in decades. Instead of pleading for scraps of spectrum, the professional audio industry could partner with agencies to modernize their outdated communications equipment, offering better technology in exchange for access to cleaner airwaves.

He suggested manufacturers and private sector innovators could help by providing modern replacements for that aging infrastructure, freeing up underused bands for shared, coordinated access. “There are military and public safety systems out there still running gear designed in the 1970s,” Sinclair said. “They’re holding huge chunks of spectrum hostage because no one’s upgraded them.”

As Moorut noted, during the 600 MHz auction, broadcasters—one of the largest groups of professional wireless microphone users—received roughly half of the auction’s proceeds, around $10 billion. That scale of compensation underscores how valuable this spectrum is to the wider media ecosystem, why the wireless production community must be included when national spectrum decisions are made, and how meaningful funding already exists to support the kind of modernization Sinclair is calling for.

Engineering Creativity Under Constraint
Despite the challenges, the show always goes on. Engineers have adapted by developing meticulous coordination strategies that resemble air traffic control. Frequencies are planned weeks in advance, with backup sets pre-programmed and tested. Large events can involve dozens of engineers managing hundreds of transmitters and receivers, all synchronized to avoid collisions.

Sinclair recalled a recent broadcast where every spare frequency was spoken for. “We had to label each transmitter like it was a boarding pass," he said. "One mistake and someone’s mic would vanish mid-sentence.” Some productions have even started reverting to wired microphones for reliability, not as a nostalgic choice but as a practical one.

It’s a strange twist: The technology that once symbolized freedom now represents a kind of scarcity. Yet within those constraints, creativity thrives. It forces precision, collaboration, and a renewed respect for the craft of live sound.

If history is any guide, the demand for wireless bandwidth will only grow. Each new generation of mobile networks (5G, 6G, and beyond) will hunger for more spectrum. Without deliberate protection for professional audio, the remaining white spaces could vanish entirely.

Spectrum is a shared public resource. Every wireless signal, from a singer’s microphone to a teenager’s smartphone, travels through the same air. What’s at stake isn’t just bandwidth, it’s the ability to express and connect through live sound.

The professional audio community has always been inventive, finding ways to make art work under constraint. But the next chapter will depend on collaboration—engineers pushing technology forward, manufacturers sharing innovation, and policymakers ensuring that culture has a place in the spectrum. The future of wireless audio won’t be about finding empty space. It will be about learning how to share it wisely.

This op-ed originally appeared on our sister brand AV Networks/Systems Contractor News.

The 600 MHz wireless spectrum auction has come and gone, taking some television stations off the air, forcing more than a thousand others to relocate, and causing repercussions that are starting to trickle all the way down to wireless device users. It was already apparent that owners of equipment operating in the auctioned spectrum would need to replace or reband their devices in order to avoid interfering with the mobile devices that will soon be operating there, but many were planning to put this off as long as possible.

With announcements coming from the auction winners of accelerated rollouts of 600 MHz mobile devices, there is no longer any time to waste. Wireless device issues are already on the increase as new devices are lit up and tested, with users puzzled as to why their previously fine wireless systems are suddenly giving them trouble. Though this has resulted in problems for wireless users, it has, perhaps inadvertently, created a place for engineers who can advise customers on their wireless issues, especially if they are able to perform wireless frequency coordination. Some of these calls have come my way, which caused me to take a fresh look at the problem and the newly available tools to help us deal with these issues.

INTERMODULATION DISTORTION

At its most basic, coordinating the frequencies of wireless devices is as simple as ensuring that all transmitters are operating on different fundamental frequencies, but of course, things are never that simple. Those fundamental frequencies have harmonics with enough strength through at least the fifth order that they can interfere with the frequencies of other nearby transmitters, resulting in intermodulation distortion. This typically manifests itself through popping or other unwanted noises that emanate from the receiver, usually at the worst possible time. 

[Read: FCC To Hone Wireless Mic Rules]

Calculating the harmonics of fundamental frequencies is easy, with the second harmonic double that of the fundamental, the third harmonic triple, and so on. For instance, a fundamental frequency of 626.200 MHz has a secondary of 1252.400 MHz (1.2524 GHz), and a third of 1876.600 MHz (1.8766 GHz). A single transmitter operating on its own in an area of clear spectrum will have no problem, but as soon as a second transmitter is powered up things get complicated, and the complexity increases with each transmitter added to the system. As soon as more than one transmitter is online we must determine whether the frequencies of each will interfere with the other, and the best way to do this is by using frequency coordination software made specifically for this purpose.

However, before we can coordinate the frequencies of the devices we know about, we need to figure out if other devices might also cause interference, a process done by performing a frequency scan of the area using an RF spectrum analyzer. These devices monitor and display RF spectrum activity over a specified frequency range. After running the scan, the analyzer generates a report which gets imported into the frequency coordination software along with the data from our known devices. 

Most frequency coordination software also includes the ability to pull in data for local television stations, which needs to be factored into the intermodulation calculations along with all the other data we’ve gathered. Once all the data is loaded, the software calculates any conflicts and suggests changes to the fundamental frequencies of the transmitters in order to get all the devices to play well together.

THE AUTO-SETUP OPTION

It is theoretically possible to eliminate almost all of this work by using the auto-setup features included with some wireless systems, since it polls the wireless spectrum and automatically assigns the best frequencies for all transmitters in the system. Unfortunately, auto-setup typically requires that all devices be from the same manufacturer and be banded in the same frequency range. Most real-world audio systems contain devices from multiple manufacturers with transmitters banded across multiple ranges. 

Building a system of wireless microphones, in ear monitors, and wireless intercom stations from a single manufacturer, that meets end user requirements, can problematic if not impossible. Still, auto-setup solutions are an excellent option for simple systems, or systems engineered this way from the outset, but most systems which have evolved over time are far more complicated than auto-setup can handle. Still, anyone who has decided that now is the time to replace their transmitters should consider new systems that are frequency-agile with the ability to manage frequency coordination without additional tools.

The good news for anyone given the task of wireless frequency coordination is that RF analyzers and coordination software tools are more widely available and affordable than ever before. RF analyzers now cost from tens of thousands down to hundreds of dollars and coordination software from hundreds to tens of dollars. The precision of the analyzers and comprehensiveness of the software is what sets them apart, with the more expensive options offering more features and generally making life easier by reducing the amount of work required.

Back when I worked for a large media company, our coordination work was done with a very high-end Anritsu analyzer coupled with the Intermodulation Analysis System (IAS) software from Professional Wireless. These days my toolset is far more modest, with an RF Explorer analyzer, Touchstone analyzer software for RF capture, and Shure Wireless Workbench software for coordination. Using Wireless Workbench with devices from other manufacturers is not a problem, but it requires building device profiles for those not included. The process itself is much as described earlier—connect the analyzer, gather RF data, pull all data into the coordination software, run the analysis, then make any necessary frequency changes to the transmitters. It doesn’t hurt to run another coordination once things are changed, just to double-check that everything is working without conflict.

While wireless coordination will most likely be needed for 600 MHz devices, it may also be necessary for 470–512 MHz devices if you happen to be in one of 11 large US metro areas, because that spectrum has been designated for public safety (T-Band) land mobile radio use.

Jay Yeary is a television engineer who specializes in audio. He is an AES Fellow and a member of SBE, SMPTE, and TAB. He can be contacted through TV Technology magazine or at transientaudiolabs.com.