Chris Phillips has spent over 20 years in the industry working in Product Management, Market Development, and Project Engineering roles after graduating with a degree in Commercial Music Business from Missouri Western State University. His integration experience has extended to all phases of project work including system design, DSP programming, and final commissioning for large venues. Chris is part of Sennheiser’s Global RF Experts team and works on the Technical Applications Engineering team for Sennheiser for the Americas.
Over the last several years, whenever the wireless spectrum has been discussed in Houses of Worship, it’s usually not because good things are happening to it. However, there’s been a lot of buzz lately about WMAS technology and how it can revolutionize the way the wireless spectrum is managed.
TFWM: First, can you offer a brief overview of the current state of wireless management in the US?
Chris: Today’s wireless microphones are narrowband devices (200 kHz bandwidth) and are operated with transmitter-receiver pairs. When planning frequency coordination, it is important to keep wireless microphones and in-ears apart as transmission power will add up, which can be challenging due to the shrinking amount of available spectrum for wireless microphones, leading to potential for interference and mic failure.
Backstage at concerts, houses of worship, or other live events, you’ll typically find large racks with microphone receivers and in-ear transmitters that can sometimes take up a lot of space.
TFWM: Can you tell us what WMAS is, and break down why this technology will be a game changer for houses of worship?
Chris: WMAS is a technology for wireless audio transmission. Product development is ongoing.
Places of worship face the same issues as other live events – congested spectrum, RF fading. Due to the multi-channel nature of the technology, WMAS is especially interesting for places of worship that have live bands as an integral part of their services.
It will be a dream come true for front of house engineers who manage large scale AV operations like bigger houses of worship or megachurches. WMAS will tackle many of the common pain points for sound engineers, including RF fading and multi-path dropouts, while maximizing the increasingly scarce frequency resources available across the US.
At the same time, it is important to remember that WMAS will be for multi-channel applications. Wherever just two or three mics are used, narrowband will be the better option. Both types of transmission can co-exist, the same guidelines for frequency planning apply as today.
TFWM: Why haven’t 6-MHz channels been looked at in the past for wireless devices?
Chris: Until this point regulatory bodies in various regions have limited the carrier width to 200 kHz for wireless microphones and IEM systems operating in the UHF spectrum. Recently Sennheiser along with other manufacturers have been working with these regulators to adopt wider bandwidths. This is really driven by the need for spectrum efficiency which WMAS allows.
TFWM: In the simplest terms possible, could you explain how Sennheiser’s WMAS technology works, and how the combination of wireless signals would work within the WMAS framework?
Chris: We can use the example of a typical church deploying 16 wireless microphones and 8 stereo in-ear monitors. Today we would build antenna distribution separately for both the wireless microphones and the IEM transmitters. We would also need to carefully frequency coordinate as the spectrum below 600 MHz is increasingly crowded. With Sennheiser’s approach to WMAS the entire system could potentially operate on the same 6 or 8 MHz RF channel while maintaining the audio quality, low latency, and RF range required for the highest levels of live performance.
With WMAS technology, we are re-thinking wireless audio transmission in multi-channel applications such as big live events, houses of worship, theaters, and broadcast studios – wherever many audio channels are up in the air. Sennheiser’s implementation of WMAS is essentially a bi-directional wireless broadband technology, which combines microphones, in-ears, and remote control in just one broadband RF channel. WMAS would tackle many of the common pain points for sound engineers, including RF fading and dropouts, while maximizing the increasingly scarce frequency resources available across the US.
While the products deploying WMAS are currently in development, once realized, these forthcoming solutions will enable a single bodypack to simultaneously support a wireless mic and in-ear monitor for artists. With this, the solution will free up space backstage at events, taking away the need for busy racks of receivers and transmitters as a single base station would feasibly handle many inputs and outputs. Live audio engineers and frequency coordinators will benefit from additional control, less clutter and negligible RF fading, amongst many other advantages.
TFWM: WMAS is already accepted in Europe. How has this impacted wireless users there?
Chris: While our products deploying WMAS technology are still in development, Marco Völzke, a freelance frequency coordinator and one of the early testers of the technology was blown away by the quality of the digital in-ear system. In a recent interview, Völzke stated he is “really excited to see what the creative industry will do with these systems – maybe immersive audio projects. I think this is the first system that you can try out for this and impress artists and listeners. This might be a new type of event that has not been possible before.”
Another revolutionary innovation that WMAS will enable is the ability to have both wireless microphones and IEMs on the same device. This does not exist with current narrowband transmission as it requires spectrum separation and additional coordination, which brings greater risks for fading and dropouts.
TFWM: How would the power transmission needs for WMAS differ from current wireless spectrum devices?
Chris: WMAS is a broadband technology, Sennheiser’s implementation would use a full TV channel (6 or 8 MHz depending on where you are in the world) for audio transmission. The same bodypack can be a mic and in-ear monitor at the same time – just one pack for the artist. Backstage space requirements are drastically reduced not only because of the combined pack but because one base station could feasibly handle many inputs and outputs – it will be possible to take a multi-channel system with you on a plane.
TFWM: What problems is WMAS designed to solve?
Chris: Initially, Sennheiser’s WMAS developers wanted to solve the problem of RF fading. If you will, RF fading is the natural enemy of any wireless audio transmission. When radio waves propagate, they hit obstacles, even if it’s just the floor, and you will have the signal arrive at your receiving antenna with time delay. Thus, waves can enhance each other, or cancel each other out (dropouts). As research progressed, the many advantages of broadband transmission became obvious, such as the better frequency efficiency, the easier re-use of frequencies, for example at festival sites or in broadcast complexes, the scalability of audio quality, etc.
At the same time, the wireless spectrum, particularly in the US, has become an extremely limited resource for wireless microphone operators. WMAS technology also enables us to maximize the available spectrum by increasing both channel density and performance when compared to the narrowband systems.
