Tech Focus: Surround Microphones, Part 1 — Next-Generation Audio Immersiveness Nears, or Not

More than a decade has passed since broadcast audio moved into the surround era. Today, it’s poised on the brink of next-generation audio (NGA) immersiveness. Yet the dedicated surround microphone remains a unique niche in pro audio in general and in sports broadcasting in particular: somewhat exotic, technically sophisticated, relatively expensive, alluringly complex yet seductively suggesting a simple solution to a complex problem.

Cost is a major factor, as is the architectural diversity of many sports venues, which complicates the predictable placement of mics. DPA, Sanken, and Holophone surround microphones can have unit prices of $5,000 or more, and SoundField’s DSF-B Digital Broadcast Package ranges into the low five figures, including its processor. However, manufacturers have also created simpler and lower-priced surround-mic products, such as Holophone’s Sports Mic and HD3, which sell for $1,000 and $2,000, respectively, a fraction of the $6,000 cost of its H2 Pro flagship model.

But there are also cultural differences: whereas surround mics are a small niche in the U.S., they’re a regular component of the broadcast-sports audio infrastructure in Europe. Karl Malone, director of sound design for all of NBC Sports, notes the overwhelming dominance of a single sport (soccer) there, the limited number of national broadcasters, and the architectural uniformity of its stadiums make it a good fit for permanently installed dedicated surround microphones.

“UK stadia generally follow a certain build structure, which places camera positions and announcers under an extended roof structure generally in the 130- to 160-ft. height range,” he explains. “The announcer position can either be hanging from that roof closer to the rear stadium wall or extended out as much as 30 ft., which, when you hang a surround microphone system, will give you lots of left-surround/right-surround crowd [sound] behind the microphone.”

In the U.S., by comparison, the variety of major-league sports, the diversity of their venues’ architectural designs, and the scattering of their broadcast rights among a half dozen major networks and a growing pool of regional sports networks, plus the relative independence of the freelance base of A1s and A2s here versus the staff-based personnel in Europe, work against a uniform approach to capturing surround elements.

Though acknowledging that the time required to properly position and test surround mics in live sports can be challenging, Malone points out that the huge variety and relentless scheduling of broadcast sports in the States, combined with the thinness with which networks’ field-ops assets are distributed, actually argues for more use of dedicated surround mics.

“When using a fixed array [of microphones to capture the surround field], the placement is crucial, and that can be difficult in a one-day set and shoot,” he says. “If there is time to mount the mic correctly, then [surround microphones are] a great tool in providing surround crowd ambience. The advantage of having a phase-coherent downmix makes the resulting signal clean of potential phase issues.”

That, he continues, would be even more apt in an immersive sound environment. “In any live Dolby Atmos or DTS:X mixing, having a stable 5.1 bed from a fixed surround mix would definitely give room for the engineer to build objects around it and above it, whilst all the time checking and maintaining the downmix for the stereo listener,” he says. “Perhaps the market will be reinvigorated when we start to hear the next-generation audio systems delivering even more-immersive productions.”

The Manufacturer’s Perspective
Manufacturers of surround microphones say the shift to immersive audio could very well jump-start the category. Jim Pace, president of Plus24, which distributes Sanken’s WMS-5 surround microphone in North America, says activity has been picking up first in cinema markets, where formats like Atmos and DTS:X already have significant traction, with episodic television increasingly using that type of mic, in anticipation of broadcast’s future transition to NGA.

“That’s the path that this will likely take to broadcast sports,” he says. “Immersive audio is going to be great for live sports because they’re emotional and immediate. Surround microphones are a good tool for capturing that.”

However, sales and rentals of dedicated surround microphones may actually have receded in recent years. Rod Allen, senior product manager at Bexel Global Broadcast Solutions, says he saw a spike in interest a few years ago but that has faded. He observes that the ability of A1s to remotely steer the capsules on SoundField’s DSF-B MKII microphone and its DSF-2 MKII microphone controller stirred interest for a while. More recently, he says, rentals for those types of applications have shifted to SoundField’s UPM-1 stereo-to-5.1 upmixer, which automatically generates a surround sound field.

“There’s a lot going on in the A1 booth, and a dedicated surround microphone might be one more thing that distracts them,” he speculates. “They’re concentrating on building a show, and it’s easier to deal with stereo sources and then upmix them with a simulator.”

Joe Prout, broadcast specialist at Dale Pro Audio, largely concurs, also citing U.S. broadcast culture, where freelancers may find themselves in unfamiliar remote units facing tight deadlines, unlike European A1s, who usually stay with the same unit for years at a time. As a result, he says, “our major broadcast-sports mixers and sound designers choose to go a different route … in terms of how they create their surround beds for their mixes.”

As surround sound moves from the 5.1 model into a much denser multichannel future, it may be an ironic anecdote that the tools to create it will remain rooted in the mono and stereo microphones that most domestic A1s deploy to create their surround fields. But the dedicated multicapsule surround microphone will always be on the shelf, within arm’s reach.

Click here for Tech Focus: Surround Microphones, Part 2 — A Look at the Latest Products