Sound Devices RF Applications Engineer Gary Trenda on Wireless Audio at the Super Bowl LVI Halftime Show 

REEDSBURG, WISC., February 21, 2022 – Gary Trenda, RF Application Engineer for Sound Devices, speaks about his experience working the Super Bowl LVI Halftime Show as an RF Technician.

How did you get involved in the halftime show? 

I got involved in the halftime show through my work with James Stoffo and Professional Wireless Systems (PWS). I’ve known James, the founder of PWS, for over 20 years now. Starting around 2014, I was working as a freelance RF Technician and had the opportunity to work several annual events with crews from PWS. This includes award shows like the Latin Grammy awards, large corporate events for Salesforce, SAP, and others. James was the RF Engineer for the Super Bowl Halftime Show for many years. After Super Bowl 50, he needed to dedicate more time to his job as the CTO of Radio Active Designs, so I was asked to take over the lead role on that RF team.   

From left to right: Gary Trenda, Kasey Gchachu, Cameron Stuckey

This year was my sixth Super Bowl and I work with a great team. The other two RF Technicians on the team are Cameron Stuckey and Kasey Gchachu. We take care of all the entertainment wireless systems, including wireless microphones and in-ear monitors. We have wireless equipment on the field for pregame (National Anthem, America the Beautiful, etc.) and halftime, as well as the referee microphone and a microphone for the post game Lombardi Trophy presentation. We work with an audio team from ATK AudioTek led by Paul Liszewski, Kirk Powell, George Schwartz, and Brett Velasek.  

What are the challenges of doing the halftime show? 

Our two main challenges every year tend to be coverage and congested spectrum. As mentioned, we set up two zones this year, one on each side of the field. In the past, we’ve needed to deploy up to four separate RF zones to extend coverage to various areas of the stadium.  

A congested RF spectrum is always a challenge, and that was especially true in Los Angeles. The systems we deploy generally operate in the UHF DTV spectrum (470 – 608 MHz). In Los Angeles, that spectrum is almost completely full of T-Band Radio (mainly 2-way radio for public safety) and Broadcast DTV stations.   

The NFL receives requests for hundreds of channels of RF equipment from users at the Super Bowl. The NFL frequency coordination team, led by Loren Sherman, does an excellent job allocating frequencies to users, but in a congested environment, the requests can exceed the spectrum available.  

We’ll end up talking with the NFL frequency coordination team well in advance of the Super Bowl to develop a band plan for our equipment that fits the city the game will be in. In recent years, this has also meant looking at alternate spectrum outside of the core UHF DTV band. We’ve needed to use all the areas available to us in order to get enough RF channels for reliable operation.   

Can you walk us through your set up? 

It can vary by stadium, but we generally try to reserve some space on the sidelines for our “RF World” between the 30-yard line marks on the camera side of the field. “Camera side” meaning the side of the field where the primary camera positions are set up. This gives us a good antenna location, especially for the ref mic and halftime show.  

We’ll generally set up an IEM transmit antenna at RF World and run low loss coaxial cable to approximately each 30-yard line mark on our side of the field. We’ll deploy receive antennas there for our primary A and B receive sites.  

In recent years, we’ve deployed additional antenna zones using an RF over Fiber system (RFoF). This year, for example, we ran fiber to the opposite side of the field and setup a mirror image of our antenna system. Having the ability to send IEM transmit from either side of the field can be helpful if the halftime set pieces end up shielding the RF signals. And having C and D receive antennas means you’re always relatively close to a receive site.   

We used PWS helical antennas and a combination of PWS and WisyCom distribution gear. The helical antennas were both UHF and STL band. From WisyCom we had BFA, MAT, MFL, and SPL distribution equipment. We used a PWS Alpha Quad-8 distro to feed our Quadversity™ receivers. There were also custom tuned cavity filters deployed between the distro and receivers. 

The wireless microphones were mainly Axient Digital from Shure and Digital 6000 from Sennheiser. The In-Ear Monitors were Shure PSM-1000. With Axient Digital, we made use of some of the advanced features, including frequency diversity, Quadversity™, and ShowLink®. We also shared our RF distribution system with some transmitters and receivers from Westwood One radio. That required a VHF band LPDA antenna for their IFB system. It really was quite a range of equipment across the RF spectrum.  

Did you use any Sound Devices / Audio Limited wireless?  

No. There’s typically the need for handheld microphones with an entertainment wireless system, which is something Sound Devices doesn’t make. At the Super Bowl we try our best to accommodate the performer’s equipment preferences. Handheld microphones can be a very personal thing for a performer. They get used to the sound of a particular microphone element and the associated wireless system. Performers can also be particular about the size, weight and even color of their microphone. We try to put together a band plan that can work with a variety frequency ranges from various manufacturers. This year we ended up putting the Sennheiser microphones in the 600 MHz band and Shure microphones in STL band. I did see quite a few Sound Devices mixer/recorders being used by the various ENG, behind the scenes, and documentary crews on site. 

When you’re not freelancing as an RF Technician, you work as an RF Applications Engineer at Sound Devices. Tell us about your role. 

I really enjoy Applications Engineering at Sound Devices. I work full time out of the Madison office and get to work across several functional groups within the company. I help the Technical Support team with questions about RF system deployment. I interface with the product team and discuss how wireless audio systems are used in the field.  I work with Engineering evaluating new and existing product features. I also help with tech tips and videos explaining Sound Devices wireless products. If there’s any time left, you’ll sometimes see me answering a few of the more detailed technical questions about Sound Devices wireless products on social media. Additionally, I continue to work several events a year as an RF Technician and Frequency Coordinator. From the perspective of a system user, I very much appreciate the emphasis Sound Devices puts on staying current with audio wireless technologies and real-world applications. 

Can you share a tip that you wish you had known at the beginning of your career? 

I wish I had a better understanding of RF gain structure when I started. Most of the users I talk with have learned audio first and RF second. I find it helps to draw parallels between the two. For example, there’s a common misconception that RF amplifiers can be the best way to solve reception problems. While this can sometimes be true, it’s sort of like saying that most audio problems can be fixed by turning up your preamplifier gain. At some point the signal will overload, becoming clipped and distorted. The same is true for RF. An RF signal that’s too strong can also negatively impact performance. As users learn more about RF, they begin to understand transmission power, antenna gain, free space path loss, directional antennas, cable loss, filters, etc. These all play a part in the overall RF distribution system and optimizing the RF gain structure generally leads to reliable wireless system operation.

What made this year’s halftime show fun? 

I very much enjoyed the concept of this year’s halftime show. I thought the various sets showing Dr Dre in his recording studio, Snoop Dogg in his house, 50 Cent in the club, etc. made it visually interesting. Along with that you’ve got hip hop legends and iconic songs delivered through a sound system with the sonic impact you’d expect for music of this genre. It was a great show.