Tech Focus: Immersive Audio, Part 1 - A Toolkit Focused on Capture Manufacturers are making the mics more accessible and easier-to-use By Dan Daley, Audio Editor Wednesday, December 4, 2024 - 7:00 am
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Conversations around immersive audio for broadcast have a tendency to focus on the outputs: mostly, the number and placement of loudspeakers, especially the four overhead. With Dolby Atmos the dominant immersive-audio format in the U.S., it's usually a foregone conclusion. However, getting sound into the immersive machine and processing its audio is a more complicated proposition. Microphones to capture it and consoles to process and mix it offer a small but growing array of increasingly necessary options. This month's Tech Focus looks at both, starting with microphones.
Multichannel Mics The 2024 Paris Olympics were a case study in immersive capture. NBC Sports deployed 3,680 microphones, including multichannel mics, as part of its immersive-sound strategy to, as Olympic Broadcasting Services (OBS) Senior Manager, Audio, Nuno Duarte described it at SVG Europe's Sports Audio Summit 2024 in November, provide a consistent product across every sport, all in 5.1.4, for two weeks straight.
Interest in the multichannel-microphone category is accelerating, says Joel Guilbert, audio specialist, Dale Pro Audio. Citing several examples, including the Voyage Spatial Mic and Shoeps ORTF-3D array, he points out that network capabilities are making these multi-capsule mics easier to manage.
We're seeing more traction with [Power-over-Ethernet]-equipped multichannel mics, he says. We see this as coming from a number of fronts. One is that, with Dante and PoE connections, it's more plausible to connect four-plus mic capsules without having a massive snake or one with tricky smaller connectors. Also, more and more network infrastructure is available. Camera CCUs and most consoles have some kind of Dante connectivity, or most trucks or facilities have some kind of fiber available to use. The necessary accessory items are becoming available without being super-specialty items. We've put together kits with solid, relatively off-the-shelf PoE injectors with fiber converters for pretty low cost. These tools all make it easy to work with these [kinds of] mics in a real-world environment.
Single-Point and Multichannel Approaches DPA Microphones 5100 mobile surround microphone
An early stalwart of the category, DPA Microphones 5100 mobile surround microphone is a self-contained plug-and-play solution. It was introduced in 2008 for 5.1-audio capture (priced at $3,780) but has been deployed in immersive applications as well. Among its applications for sports are Winter Olympics ice skating and Wimbledon Court 1 in 2023.
However, according to DPA Global Support and Business Development Manager Paul Andrews, use of multiple single-point microphones in arrays, the original technique for capturing surround sound, remains a valid approach to capturing immersive sound as well, offering more-flexible configurations. Some of our users - Sky Sports, for instance-prefer using single-channel microphones in multiple places to get a more immersive field than just [a single multichannel microphone] might provide.
But, even within those arrays, he points out, the multichannel 5100 has been used to provide the four height channels of the Atmos format. There are a number of combinations [of single-point and multichannel mics] you can use to achieve immersiveness, depending on the kind of sound you want.
It's All About Technique That's also how Sennheiser envisions its new MKH 8030 ($1,499) figure-8 polar-pattern microphone. The latest in the 8000 series are being deployed for immersive capture.
Sennheiser MKH 8030
For sports, says Brian Glasscock, project manager, Sennheiser Pro Labs, we've seen a variety of microphone techniques. For crowd noise, we've seen a lot of benefit from using a dual-diaphragm mic, like the MKH 800 Twin, especially in these kinds of non-coincident microphone techniques. With the 8030, you can achieve that effect with a double-midside [configuration] that's easily placed somewhere and is less complicated for cable running. Choosing [specific microphones and techniques] is really about application and the constraints of time and locations or other types of limitations that sports [productions] may face.
Sennheiser also has a single-mic solution for immersive capture: the AMBEO VR ($1,499) with its four matched cardioid capsules in a tetrahedral arrangement. However, Glasscock considers a unit like the 8030 a keystone for the array of microphones already aboard most remote-production trucks.
We see a lot of value in that, he says, because people aren't going to want to buy a different mic array for each application. I think having this toolset of baseline, high-quality microphones and maybe a couple of specialty microphones able to be used in different arrangements makes sense for the immersive application as the way most people will go.
A New Approach Voyage Audio SpatialMic
Voyage Audio is the new kid on a small but growing block, and its SpatialMic has a kind of Millennial-esque flexibility: it's designed to accommodate various output configurations - stereo, 5.1.4, 7.1, etc. - internally and to adjust to future ones, such as 4.0.4 (no LFE channel) via firmware updates.
It's kind of interesting with broadcast right now, says Voyage Audio co-founder Steve Silva. It isn't full Atmos yet, but I think that's the trajectory and the goal for everybody. There's still plenty of 5.1 around sports, like the Olympics, so the goal is to expand on what's being done today. The demand is for a tool to get to those formats quickly, easily, and out of the box, so to
