Tag: RF

All-star RF Engineer Ali Viles on the ‘Impossible Gig’ made possible with Sound Devices Astral ARX32

25 years since their debut performance at the festival, Coldplay took to the stage to headline the 2024 Glastonbury Festival – one of the UK’s premier annual live music events. Attended by more than 200,000 people, the guest star-studded performance – which included cameos from a diverse range of collaborators including British rapper Little Simz, Nigerian Afrobeat legend Femi Kuti, and Back to the Future star Michael J. Fox among others – was a breathlessly energetic celebration of the band’s past, present, and future wrapped into a singularly ambitious stage show. 

One of the key architects of the performance from behind-the-scenes was RF Engineer and Mission Control Ltd Director Ali Viles, who was tasked with the seemingly impossible job of delivering the band’s wireless audio requirements on a size and scale never before attempted at the festival, while ensuring a seamless, high-quality experience for the band and their guests. The quantity of guests involved in Coldplay’s headline extravaganza pushed the RF requirements for this show way beyond the capabilities of the band’s normal touring system and demanded some lateral thinking when it came to spectrum management and coordination. Viles collaborated with audio equipment manufacturer Sound Devices in partnership with Solotech and Adlib, utilizing the enormous tuning range of the Sound Devices Astral ARX32 Wireless Receivers to help deliver the high channel count required for this high-stakes performance.

Pushing the boundaries of possibility 

Coldplay are in the third year of a record-breaking global stadium tour, performing to packed stadiums of 60-80,000 fans a night. Their touring production, spread over three stages across the stadium floor, is a complex and demanding RF environment and for Glastonbury, a global live streamed performance at an outdoor festival show to a significantly larger audience, Viles knew that extraordinary planning and execution would be required, “Coldplay are very dynamic performers and hold themselves to incredibly high standards when it comes to delivering on gigs like this, and those standards naturally extend to the quality of service of their in-ears and wireless microphones,” explains Viles. “Outdoor performances in general can be extremely volatile for wireless equipment, and at a festival like Glastonbury, where there are around 1000 RF carriers in use across the festival site, it’s above and beyond what we would normally have to deal with during a gig.”

“There are a number of elements working against any RF engineer at a major festival such as Glastonbury: RF interference resulting from the density of other users on site, the potential risks from any rogue unlicensed and uncoordinated users, and unfavorable atmospheric conditions are considerable, and we knew it would be quite the challenge to deliver the more than 160 RF carriers required for this performance. Thankfully, Glastonbury’s Comms and Production teams are rigorous in their management of spectrum allocation around the huge site.”

In addition to conditions imposed by the radio frequency, environmental, and regulatory factors, the scale of Coldplay’s stage setup also added another layer of complexity to the performance. Spread across Glastonbury’s massive Pyramid stage with two large wings on either side and an extra ‘C stage’ in the middle of the audience, the band needed spotless wireless microphone and in-ear coverage for themselves and over 50 guest performers who would be appearing alongside them. All this was compounded by the fact that the Glastonbury Production team also had to deliver (on time) the rest of the amazing Pyramid schedule and live broadcast that day. “The brief was that we had to deliver seamless coverage across the entire stage with no restrictions for over 160 RF carriers at the level of quality and reliability that the band are accustomed to,” says Viles, before adding with a chuckle, “Ofcom [UK Radio Licensing Authority] initially told us that it was simply not possible!”

“Most radio mics and IEMs operate between 470 and 698 MHz in the UK and that spectrum was already saturated by the quantity of other users at the festival site. In order to achieve the extra channel count we needed, we first had to ascertain what other RF spectrum may be available at the festival and then negotiate access to it with the UK licensing authority. Working with the incredible team at Mission Control, we were able to find and then successfully negotiate exclusive access to the additional spectrum that we needed to make the show work. It was then time to go looking for the hardware that could work in these additional blocks of spectrum, which were well outside the tuning range of traditional radio mic and IEM systems. This is where Sound Devices came into the story.”

Agility, stability, and HexVersity^®

Familiar with the Sound Devices Astral^® series of wireless receivers and seeing the possibilities inherent in the extended tuning range of their proprietary SpectraBand™ technology, Viles contacted the Sound Devices team to explore solutions that could answer some of the challenges he was facing with the upcoming Glastonbury set. “It was still early days for Astral ARX32 but its vast tuning range opened up new ways to deliver some of the guest microphone channels that we needed to make the gig work – something that ultimately no other brand was able to achieve for us as a single package,” he explains. “Being able to design a receive system for a significant section of our guest performers around the Sound Devices Astral ARX32 hardware enabled us to not only work with the more obscure spectrum that we had secured for the band’s performance, but also remain frequency agile, allowing us to use the same hardware in other frequency bands if we ran into difficulties on site, which gave us an enormous peace of mind that we would be able to deliver what was needed.”

“The breadth of Astral ARX32’ tuning range is something that surpasses anything else that’s out there.”

Working alongside Sound Devices’ RF Application Engineers Gary Trenda and Cody Heimann, Viles designed a system around a compact set of three Astral ARX32 receivers to provide wireless coverage for the entire stage area and wings. The three operating receivers were cascaded together and deployed in HexVersity mode, which allowed for 6-antenna diversity across the available bandwidth that Mission Control had managed to license for them above 1000 MHz “With 1000 or more carriers in use across the festival site, frequency agility was pivotal for delivering what we needed to achieve, and Astral ARX32 gave us that flexibility in a way that nothing else could,” he says. “From a workflow point of view, it was invaluable to be able to monitor the spectrum continuously with Astral ARX32’ RTSA – giving us a level of detail that allowed us to understand exactly what was going on and react quickly to any changes in the spectrum. The ability to remotely change transmitter pack settings via NexLink without having to manually sync anything allowed us to work very quickly and waste very little time on setup, both during rehearsals and at the festival itself.”

Andy ‘Baggy’ Robinson, Sound Devices Vice President of Sales, continues the story: “Having personally been tasked with impossible gigs in the past, it was a privilege in my new role at Sound Devices to be part of the team supporting Ali with this RF challenge. The way Ali and the Coldplay team took the Astral ARX32 and fully utilized its features to overcome the many challenges was truly impressive.”

Looking towards the future

For any of the tens of thousands watching live at Glastonbury or the millions streaming worldwide, they witnessed an extremely experienced band at the very top of their game deliver a truly breathtaking headline performance on the legendary pyramid stage. For Viles, after months of planning and hard work, the performance came together exactly as intended, demonstrating a compelling model for what may lie ahead in the future of RF in the touring market. “The show itself went seamlessly and, once we were set up, we were easily able to monitor the Sound Devices system and remotely make any changes to the hardware, even while the performers were wearing their transmitter packs,” he continues. “Seeing how the system works opened up an enormous range of possibilities for how we may be able to use this equipment at other events around the world in the future.”

“When planning tours there’s always a balancing act between weight vs. cost vs. flexibility of any hardware that you use and finding the right balance between those three metrics is becoming more imperative,” he continues. “Something many artists are also sensitive to now – and Coldplay especially – is improving the sustainability aspects of touring and choosing equipment that is compact, rock solid, and versatile. The high channel count, small form factor and vast tuning range of the Astral ARX32 is unbeatable, replacing a 150-kilo rack of hardware with a single 1U box and doing the same job, but better. It’s a huge benefit.”

“Many people have little or no understanding of RF and what it takes to deliver an event like Coldplay’s headline show at Glastonbury in 2024” he concludes. “It’s an odd discipline and very few people truly grasp how it works, and how unlikely it is to work reliably. Being able to utilize Astral ARX32 at this show was a total game-changer. It worked brilliantly and I can’t wait to take it even further in the future.”