Tech Focus: Immersive Sound — Sports Venues Turn to Multichannel Mics
A look at mics that capture full-spectrum audio from all directions
As immersive sound goes increasingly live, the means by which it can be captured is also stepping up. Some of the microphones made for applications beyond two-channel stereo are intended for broadcast applications. However, they and others are also being used for field recordings for films, gaming, VR/AR, and other media.
These mics, characterized by capsules with multiple diaphragms for capturing full-spectrum sound from all directions and software processing to encode/decode that directional audio into various surround-type delivery formats or into full 360-degree ambisonic sound, have been finding their way into sports venues. As stadiums and arenas look at Wi-Fi–enabled smartphone AR apps for fans in the stands, the multichannel mic’s presence may soon take on another level of meaning there. Here are some of the leading multichannel microphones.
The Core Sound OctoMic second-order ambisonic microphone boasts a larger sweet spot that can accommodate multiple listeners without degrading a recording’s sound-location perceptual cues. According to the company, the OctoMic can be used 50% farther from the sound source while maintaining the same directivity index. OctoMic’s frequency extends below 30 Hz, and its treble response is above 18.5 kHz, with very low handling noise.
The HEAR360 8ball “omni-binaural” microphone is camera-mountable and provides eight discrete channels. At over $2,000, it’s also one of the most expensive choices, but it also works with any eight-channel recorder, has a 20-Hz to 20-kHz frequency response, and can handle 130 dBA maximum peak SPL.
RØDE, which acquired Soundfield’s assets in 2016, has kept the NT-SF1 in the batter’s box. The four-channel microphone captures a full-360, head-trackable recording in a single mic (recording in A-format, converting to B-format) for ambisonic audio that is also compatible with Dolby Atmos.
Sennheiser’s Ambeo VR Mic offers four cardioid pattern condenser mics arranged to form a 360-degree pattern. It’s designed to work compatibly with DAWs like Pro Tools, Logic and Reason, using specialized encoding software.
The Zoom H3-VR is a basic four-capsule ambisonic mic featuring a six-axis motion sensor with automatic positioning, and level detection, attached to a four-channel recorder. One reviewer called it the “GoPro camera of VR mics”: it’s simple to operate and costs about $300. But it also supports full-sphere surround-sound recording at up to 24-bit/96 kHz, as well as real-time stereo/binaural monitoring and on-board Ambisonics A-to-B conversion. The unified single-knob gain control, LCD screen, and transport/menu buttons deliver efficient device configuration and operation. Remote access to transport controls, levels, and metadata is possible via the iOS H3-VR Control app and optional BTA-1 Bluetooth adapter.