Tech Focus: Bodypacks, Part 1 — Wireless Transmitters Are Integral to Sports Audio’s Future

COVID, encryption, and spectrum pose continuing challenges

Today’s wireless bodypack transmitters are almost nano-small, their battery endurance is reaching Tesla-envy levels, and the RF spectrum disruptions of the past few years have (mostly) settled down. However, that doesn’t mean that their designers and manufacturers don’t face other challenges.

Among the continuing challenges is the COVID-19 pandemic, which has made A2s’ task of miking athletes a fairly fraught proposition; purveyors of wireless products and services in general have spent vast amounts of time and effort developing and sharing best practices and protocols related to wiring people and things for remote audio during the pandemic. Digital encryption and adjustment to the spectrum repack also confront vendors.

“COVID was everywhere that [lavalier microphones] are used,” notes Karl Winkler, VP, sales and marketing, Lectrosonics. “Early on in this ‘adventure,’ we put together materials about using and sanitizing lavs on our website. It quickly became the most popular page on it.”

Keeping Secrets

Encryption of digital signals has become a significant issue in wireless communications particularly in sports, where coaches and athletes need to discuss strategy and tactics on the field and broadcasters want to get some of that backstage dialog on-air. Winkler says encryption offers various levels, denoted as “keys,” to sports customers according to the nature of what’s being communicated. The most secure keys allow only voice exchanges between devices, such as microphones on beltpacks and cameras, that share an encryption key.

But that information has various uses, he points out. For instance, between an NFL coach and quarterback, the signals have to be fully encrypted to avoid disclosing tactical information ahead of critical plays. On the other hand, an NBA coach’s bodypack transmitter is there to pick up the same sorts of tactical disclosures, but they won’t be broadcast until after a play is over, when they’re heard on-air as part of a replay. That latter application is often the more difficult one to get cooperation for, notes Winkler.

“Not every head coach is completely comfortable with this yet,” he explains, adding that his company’s newest digital wireless system, the D Squared, was recently expanded to four encryption keys. “Some [coaches] have to be reminded to turn the bodypack transmitter on. They’ve been using that audio in the NBA only for the last couple of years, and not everyone is completely sure about how secure encryption is. But that’s understandable, given how high the stakes are around that information.”

Spectrum Matters

Although issues around RF have largely settled down since the end of the 600 MHz incentive spectrum auction in 2017, with the repack going largely into effect through July this year, wireless designers have had to make some adjustments. For instance, Winkler cites standards body ETSI’s update in which the deviation — the maximum FM modulation of the nominal carrier frequency — of all new wireless microphone transmitters was changed to a maximum of ±50 kHz from the previous ±70 kHz.

“We know what spectrum we have to work with now, and we’ve made adjustments for that,” he says, such as expanding tuning ranges. “A few years ago, our transmitters would have had 256 channels across 25 MHz of bandwidth; now we’re up to 6,000 channels to choose from over 144 MHz. The tuning-step sizes are packed much tighter, which provides more choices for frequency-coordination planning and lets users cover more area. That’s especially necessary in dense metro areas with a lot of adjacent TV channels after the repack.”

Steadily increasing channel counts, in sports and other verticals, remain a challenge, notes Jim Lappin, product manager, wireless microphones, Audio-Technica. Therefore, A-T, like other wireless systems manufacturers, has developed its own software solutions for frequency coordination. Wireless Manager allows users to create a device list, coordinate frequencies, and, when used with compatible Audio-Technica networked devices, can scan the RF environment, generate a coordinated-frequency plan, and push frequencies to receivers on the network. The software also allows remote configuration and control of A-T networked devices and can display key system parameters in real time.

“It gives you a snapshot of the available spectrum between 470 and 608 [MHz],” he says. “Once you know where the TV channels are, you can plan around those frequencies.”

Teaming Up

Shure’s Michael Johns: “All aspects of content creation should be important to audio manufacturers, and sports is. Wireless microphones are how you get close to get that sound.”

Last year, Shure and Q5X announced collaboration around new wireless transmitters that combine Q5X’s hyper-compact form factors and safety-conscious industrial design with Shure’s widely used Axient Digital RF technology. Axient’s digital operation allows versions of Q5X’s primary models — CoachMic, PlayerMic, AquaMic — to function as digital devices, conferring key features of signal encryption and improved spectral efficiency to Q5X’s diminutive form factors. The new product — named Q5X QT-AD10 Axient digital wireless transmitter (the companies will sell it through their respective distribution channels) — also incorporates Q5X’s Remote Control Audio System (RCAS), which provides remote-control functionality: on/off, frequency, mic offset, RF power, groups, and battery level.

In addition to adding digital-encryption capability to the product line, says Q5X CEO Paul Johnson, the move also reflects sports’ deepening embrace of close-up sound.

“Athletes and talent have become more used to being wired for sound in the last couple of years, audiences have been asking for more and more of it, and COVID has only increased demand,” he says, noting that the lack of crowds during the pandemic has emphasized intimate audio in environments like golf courses and tennis courts. That has brought some risk with it, he acknowledges, adding, “I believe audiences are becoming more tolerant of that over time.”

Johnson further points out that two of Q5X’s bodypack units were worn by officials of NHL games played in the league’s two-city bubble this year: the RefMic, which allows referees to mute the transmitter between calls, and a PlayerMic, which is remotely controlled and was used to collect close-up on-ice audio played back during replays.

Recent improvements to transmitters in the form of additional remote control, he notes, allow A2s to attach transmitters to athletes’ garb — NBA jerseys, NHL shoulder pads — before the players don them, thus maintaining social distancing before games while enabling remote control of such parameters as input levels and frequency selections.

From Shure’s perspective, the venture is also an important way to increase its footprint on the microphone side, particularly the lavalier mics that are generally paired with wireless bodypack transmitters. According to Michael Johns, senior product manager, wireless systems, Shure, the company’s Twinplex TL47 subminiature lav and the more recently introduced Duraplex, which adds a high degree of moisture resistance to the lavalier, are aimed as much at the broadcast-sports vertical as at the theatrical markets they were initially designed for.

“Our core competencies, in addition to wireless-microphone solutions, have always been the diaphragms and the capsules — the microphones themselves — going back to the 1920s,” he says. “The venture with Q5X helps get our lavs and our digital technology paired with their sports-friendly form factors, all with Shure’s Axient Digital wireless technology inside.”

Shure’s strategy for the broadcast-sports market, however, might be considered more holistic than some others. Instead of viewing it as a standalone target, Johns says, the company considers content and its monetization as the long-term strategic goal, with sports one of the key sectors within that vision.

“Like other [entertainment] businesses, leagues and teams want to monetize content, and audio content has become a big part of that,” he contends, citing the broadcast and social-media programming that teams like his hometown Chicago Bears’ YouTube channel. “All aspects of content creation should be important to audio manufacturers, and sports is. Wireless microphones are how you get close to get that sound.”

The Future

As with other technology trends in major-league and top-tier collegiate sports, wireless sound has been edging into lower-tier and even high school athletics. A-T, among others, has been eyeing the burgeoning use of wireless transmitters in those echelons, particularly for referees and other officials, says Lappin.

“It’s a market that has some specific requirements, such as on/off switches that are easy to find and operate,” he says, important for semi-pro and part-time refs. “We have two levels of functionality for that: an easy-to-grab toggle on top of the transmitter and a function button that can be set as a push-to-talk switch. The idea is to make its operation truly fail-safe.”

That trend alone will ensure that wireless bodypacks remain a growth sector in broadcast audio. As Lappin points out, “No one remembers what the referees’ hand signals mean anymore. They all have to have microphones now.”

Click here for Tech Focus: Bodypacks, Part 2 — A Look at the Leaders in Wireless Transmitters