Inside the Axient Digital Micro Bodypack

Michael Johns | April 2, 2019

As product manager for Shure wireless systems, I’m extremely proud of Axient Digital. These systems have been on the market for less than two years, and have already claimed go-to status in some of the most difficult RF environments around, including the Super Bowl, Grammy Awards, Broadway theatricals, and network television. 

But beyond unique features and benefits of the system (like Dante connectivity, Quadversity™ reception, high channel density, 184 Hz tuning bandwidth, and options for ShowLink® remote control and intelligent rechargeable batteries), for me, its single most impressive element is also the smallest: the ADX1M Micro Bodypack Transmitter.

The gently rounded corners and inset LEMO connector immediately suggest that this is something different from a regular wireless bodypack – indeed, different than micro packs from Shure and competitors alike. This is the product of intensive market research. 

As a product manager, I’m naturally biased, but the ADX1M is a masterpiece of industrial design. The real beauty of the ADX1M lies in how its form factor enables its broad package of unique features, designed specifically to meet the needs of its users. 

But in this post, I want to address one of the more difficult design challenges conquered by Shure design engineers: ingress protection– or as it’s more commonly called, water resistance.

Issue: Water Resistance

Historically, one of the biggest challenges for any wireless bodypack has been failure due to liquids like water and perspiration sneaking into the electronics. When hidden inside a hot costume, sweat becomes a significant issue, infiltrating the bodypack through its connectors and battery door. Similarly, broadcasters often work outdoors in reporting the news, weather, and sports, making them susceptible to the elements. 

Over the years, theater techs and broadcast engineers have come up with myriad ways to protect bodypacks, including specialized neoprene pouches, latex gloves, balloons, condoms and even “press and seal” food wrap.

That’s why we made ingress protection one of the key goals in the design of the ADX1M micro bodypack. Our research indicated that it is one of the single most annoying problems among bodypack users. 

Challenge Accepted

We set out to achieve full protection against total immersion for 30 minutes at a depth of one meter while maintaining the compact size and comfortable contours that would set the ADX1M apart from the competition. This became one of the most difficult engineering challenges we faced. 

Here’s how we conquered it:

With every switch, seam, and connector as a potential ingress point, our approach was to physically eliminate as many of those weak points as possible. This is the reason the belt clip does not breach the inside of the case. More significantly, the requirement for water resistance is part of the reason the ADX1M has no external antenna, and no battery door. 

Eliminating the external antenna is one of the biggest advances in the ADX1M design. This is a bold departure from literally every other wireless bodypack on the market.

Shure engineers developed a self-tuning internal antenna system (patent pending) that automatically optimizes its tuning characteristics by adapting the bodypack’s RF output when worn against the body. This makes the pack much easier to hide and more comfortable to wear while eliminating another point of ingress.

To eliminate the battery door, we developed a slide-in external battery that literally becomes part of the case. The SB910M battery provides a robust 7+ -plus hours of runtime, but more importantly, it slides firmly into place, preventing any liquid from reaching the contacts. Two are included with each ADX1M purchased.

Of course, without a battery door, we had nowhere to hide the switches. That meant we could not use standard pushbuttons, toggle throws, or other mechanical switches. Instead, we chose gasketed membrane-style buttons, all sealed with an external rubber sheath – kind of like weatherstripping – that prevents liquids from getting in. 

This is not to say we didn’t use gaskets. The ADX1M’s Ultem case, chosen for its unique thermal efficiency (preventing potentially painful heat transfer to the user) and durability, is a 2-piece shell. For water resistance, the case is fully gasketed, as are the three hidden screws that connect it. 

We addressed the lens for the OLED status display with a hermetic seal between the glass and case, making that potential ingress point both airtight and waterproof.

Water resistance was also part of our choice of LEMO input connector. Not only is it significantly smaller than a TA4 (critical to the whole “micro” size requirement), but the LEMO features an internal gasket that prevents sweat or rain from getting inside the pack, even with no microphone attached. Between its size and inherent water resistance, the LEMO connector was an obvious choice. 

So that’s how we plugged every hole and blocked every possible point of ingress for sweat, rain, and any other liquid the ADX1M is exposed to. Challenge Won!

Rigorous Testing

A lot of thought went into learning how micro bodypacks are physically worn, looking for and addressing points of weakness in all operational aspects, including RF performance and moisture resistance. But before we could start selling the ADX1M, it had to be tested.

Shure’s environmental testing regimen is generally regarded the toughest in the industry. Our Corporate Quality Engineering group tests for long-term reliability, but we also have a leading-edge group called the Product Validation Lab (PVL), which focuses on user workflow and provides feedback to the product team throughout the design process. Basically, they devise torture tests to ensure that Shure products will excel under the real-world conditions they will face.

In the case of the ADX1M, we had a user-mandated goal of complete water resistance. To test it, Shure PVL engineers filled a tank with water to a depth of one meter and dropped our micro bodypacks to the bottom for 30 minutes. Afterwards, the packs were retrieved, powered on, and then tested to determine if they could pass audio. The ADX1M passed these tests with flying colors, meeting all our specifications afterwards. 

I can state with full confidence that this product was designed to not fail due to exposure to liquids on stage or in the field, whether deployed inside a bulky costume, hidden in a wig, dropped in a pants pocket, or exposed to driving rain in a stadium or theme park. It is truly water resistant.

ADX1M Delivers

Having watched the ADX1M from its initial development to release, I know that ingress protection is really just one small piece of the puzzle. But it serves to illustrate a larger point, both about this product and the Axient Digital wireless system as a whole.

Not everyone needs ShowLink, frequency diversity, or Dante networking. Similarly, not every user needs a micro bodypack. But every professional needs reliability and confidence in the products they choose. With its innovative engineering and industrial design informed by serious customer input, Axient Digitalhits every mark.

Our research told us what micro bodypack users wanted, and Shure engineers delivered. Its unique shape doesn’t look like any other micro bodypack. There are no visible antennas. No corners. Designed for A2s and wardrobe people to make it easy to mic talent, that physical design motivates people as much as its unparalleled ingress protection. 

This is a product designed to serve the specific needs and desires of a very demanding group of customers. Based on the initial success of ADX1M, you can expect to encounter this product on stage at some of the most high profile events around the world.

A successful rollout and enthusiastic customer feedback tell me that Shure has succeeded in our quest: to translate the real-world requirements of the most demanding wireless users into a physical product that meets those needs and exceeds their hopes. 

Michael Johns

Michael Johns is a Senior Product Manager in Shure’s Global Product Management group. A graduate of Columbia College Chicago’s Music Technology Program, Michael has worked at Shure since June 2000 and has led the specification of many products in Shure’s Professional Wireless category including Axient Digital and PSM1000.