Development of new technology and moving to the newly available 5GHz spectrum continue to expand the creative and technical possibilities for audio across live performance and broadcast productions.
This article was first published as part of Essential Guide: Improving Comms With 5GHz
With enhanced freedom and range, and more efficient use of the spectrum provided by digital solutions, shows are becoming more dynamic and more adventurous with deployments in increasingly complex environments such as stadiums, crowded urban areas and in venues with architectural oddities like domed ceilings. With the number of artistic, technical and logistics cues that are required for these action-packed endeavors, the use of digital wireless intercom has become even more essential.
As the range of uses for untethered, full-duplex communications continues to expand through more departments and production roles every day, much has been learned about the capabilities and limitations of existing digital wireless intercom technologies operating in the 1.9GHz and 2.4GHz bands. These areas of the spectrum have become packed with DECT and Wi-Fi -based devices used for broadcast production communications, distribution and capture — all while consumer devices continue to push for more bandwidth of their own.
Even as 1.9GHz and 2.4GHz technologies solve a multitude of problems and fulfill mission-critical roles in increasingly complex environments, the saturation of available bandwidth, constraints of legacy transmission protocols, and issues with environmental multipathing and other interference challenges have led to exploration of the possible use of the 5GHz spectrum.
The higher frequency 5GHz landscape opens up a multitude of possibilities for improvement. The increased radio bandwidth across its more than 25 wider channels (typically 20MHz each), expands data capacity, which allows for finer control, higher capacity, more robustness, flexible transmission protocols, lower latency and improved audio quality.
It was with knowledge of these benefits, and bountiful feedback from users of the Clear-Com’s FreeSpeak II®, that the manufacturer invested in several years of engineering research for its new 5GHz FreeSpeak Edge™ digital wireless intercom. Input was gathered from all ends of the production field, including architecturally challenging stadium and convention center environments, indoor and outdoor live event venues, video-wall-laden conference centers and more.
Built from the ground up for 5GHz, FreeSpeak Edge incorporates entirely new radio technology that Clear-Com developed around a specialized, IoT-proven chipset. Leveraging 21st century technologies and the immense resource and development investments that have fueled innovation for mobile and IoT devices in recent years, Clear-Com further optimized the chipset for very low-latency audio transmission. The result is a robust 5GHz solution that prioritizes audio quality over raw data transmission.
Field tests are showing that 5GHz is expanding the possibilities for digital wireless intercom technologies in particularly challenging radio environments. After participating in field trials with FreeSpeak Edge at the Canadian Broadcasting Corporation (CBC) and the Montreal Bell Arena, Geoff Maurice of Gerr Audio comments, “As a FreeSpeak user from the very beginning, it’s clear that Clear-Com has done their homework and checked all the boxes with the new Edge system - I’ve never heard something that sounded so good and covered so well. I look forward to deploying this system in some of Canada’s most challenging RF environments.”
Following a trial run with FreeSpeak Edge during their live streaming broadcast of Times Square on New Year’s Eve Corey Behnke of Live X had this to say of the system, “New Year’s Eve in Times Square is one of the most challenging radio environments, and this was the first time our field producers were able to be on a reliable comms system. It was especially helpful that it tied in with all our other systems so easily. We are often working in these very crowded wireless scenarios and it’s great to know that now we have another wireless band with Edge. People using it in the field came back to say that the beltpack ergonomics and overall sound quality of Edge was very impressive.”
Clear-Com’s field trial program has been designed to ensure that the company can provide deployment expertise and guidance based on real-world scenarios. “As leaders in wireless intercom, we realize that there are so many unknowns, particularly when you go into a new wireless band. We have incorporated extensive field trials into our development process in order to provide our users with the confidence of reliable communication and experienced customer support they have come to expect from us,” comments Craig Frederickson, Product Manager, Wireless for Clear-Com.
Interference and Multipathing
In challenging environments like stadiums, crowded urban spaces and in the presence of architectural oddities like domed ceilings, digital wireless intercom can suffer from interference caused by reflections. With 5GHz, those challenges can become opportunities. Reflections, or more specifically, the multipathing they create, can be harnessed in favor of better transmission.
Through precise engineering of Orthogonal Frequency Division Multiplexing (OFDM) radio technology, the multipathing that easily propagates among 5GHz wavelengths can be transformed into “constructive interference.” As reflections help the signal propagate, the OFDM makes the transmission more robust, helping it to survive all the extra bouncing around and deliver clear audio signal.
OFDM is also used in Wi-Fi, but whereas Wi-Fi’s priority is to maximize raw data throughput, the design priority for intercom is improved audio performance and the robustness of the radio link. The radio technology is application-specific, and therefore highly optimized for transmission of real time audio, where Wi-Fi’s purpose is generic.
Multipathing can also cause limitations in propagation. So, in field tests with FreeSpeak Edge, Clear-Com has closely evaluated the transmission distances achieved by transceivers. In a standalone test in a large domed stadium, one transceiver covered the field and stands. In the empty stadium with no body blocking of RF, the signal went half-way up the tunnels.
In further testing during a game, four transceivers covered the stands and field for 40 beltpacks, while two transceivers were used for locker room and tunnel coverage.
Roaming / Scalability
Compared to 2.4GHz technologies, 5GHz devices typically do have a shorter range compared to 2.4GHz. But that fact does allow for easier reuse of frequencies, which is ideal for high-density applications. In the relatively few cases where this might be an issue, Clear-Com’s family of products includes FreeSpeak II, which uses lower-frequency bands that can be run simultaneously to form a single, unified communications system. Overall, Clear-Com users have a lot of flexibility as they “engineer for range,” relying on a device architecture that allows for enhanced roaming across multiple transceivers, combined with deployments that maximize capabilities across spectrums.
Another 5GHz benefit for large-scale communications is that it can be managed with frequency coordination for reduced interference. Unlike DECT technologies, the 5GHz band allow users to allocate frequencies. This Static Frequency Allocation, which is coordinated with the same methodologies as in Wi-Fi, enables technicians to dedicate channels for intercom, camera remotes, scoreboards, and other devices, improving cooperability. The remainder of channels may then be used for Wi-Fi. This guarantees the bandwidth required for intercom.
Clear-Com’s field trials are showing that even in situations where there are no free 5GHz channels, systems can still coexist with Wi-Fi on channels without hurting its performance.
There are three additional controls and opportunities for fine-tuning made possible by the embodiment of 5GHz technology: Coordination, power and directionality.
Users can put their RF energy where they need it. Increased focusing capabilities allow digital wireless intercom users to narrow the likelihood they’ll interfere with other users operating in the same spectrum.
They can also tailor their system further through the reuse of channels when clean channels are hard to find, or to maximize capacity in scenarios where maximum range is not needed.
This means that at a major awards event, for example, where multiple 5GHz intercoms might be used alongside various DECT-based solutions relied upon by countless outlets, it’s possible to dial back the amount of radiated power and reduce interference on neighboring systems.
Additionally, in cases where transceivers can’t be located near enough to the operators to use lower-power, and instead high power is needed, the antennas can be swapped out for directional antennas.
The enhanced audio quality that comes along with 5GHz is due to its broad channel bandwidth, which leaves more room for audio. The result is that FreeSpeak Edge can provide up to 12kHz audio bandwidth with a lower noise floor. This enhanced audio quality and lower latency is opening up new opportunities in live broadcast where, for example, mobile announcers can use pop-up voiceover booths and a wireless beltpack for clear, full speech-band audio commentary.
Looking to the Future
With the announcement of FreeSpeak Edge, Clear-Com has solidified its position as a market leader in wireless intercom, pioneering new technologies while staying rooted in responding to the needs of its broad global customer base. By augmenting an existing product line rather than replacing it, FreeSpeak Edge can only be seen as a positive for the marketplace, providing an opportunity to capitalize on new levels of performance, audio quality, and customization now available partly due to the unique characteristics of the 5GHz band but primarily can be attributed to the innovative engineering and dedication to the customer base which is reflected in the product.