From Stereo to Full-Sphere: Why Ambisonics Matters
Ambisonics microphone arrays promise far more than conventional stereo by capturing an entire soundfield, not just left and right channels. Instead of two directional capsules, an ambisonics microphone like the mh acoustics Eigenmike surrounds a rigid sphere with dozens of capsules, enabling high-order spatial analysis and precise 360 degree recording. That density of microphones allows engineers to reconstruct a three-dimensional soundfield, steer virtual microphones in software, and perform advanced beamforming and soundfield analysis. Applications range from immersive music and film production to VR, acoustics research, and environmental soundscape documentation. The latest em64d Eigenmike continues this tradition with a sixth-order ambisonics configuration and 64 channels, preserving the 84mm sphere geometry that has become a reference for full 3D spatial audio capture. This level of resolution has historically been reserved for specialized labs, but emerging technologies are now pushing it closer to everyday production workflows.
Inside the em64d Eigenmike: A Sixth-Order Spatial Audio Workhorse
mh acoustics’ em64d Eigenmike is a complete high-order ambisonics solution packaged as a compact 64-channel microphone array. Each of its 64 elements is mounted uniformly on an 84mm rigid sphere, maintaining the proven geometry of the previous em64 model while upgrading the internal technology. The system supports sixth-order ambisonics, delivering refined 3D spatial audio capture with a frequency response from 20Hz to 20kHz, a 48kHz sampling rate, and a spatial aliasing cutoff above 12kHz. Beyond hardware, the Eigenmike microphone ships as an integrated platform: advanced beamforming, multi-track recording, and the EigenStudio software suite plus EigenUnit VST plugins streamline post-production. Users can steer virtual microphones, decode ambisonics formats, and perform complex soundfield analysis from a single environment. This tight coupling of array hardware and dedicated software is key to making sophisticated spatial audio capture practical outside of experimental labs.
Optical MEMS Technology: A New Class of Microphone Capsule
The em64d’s biggest leap comes from replacing electret condenser capsules with sensiBel’s SBM100B optical MEMS microphones. Traditional capacitive MEMS rely on a diaphragm and perforated backplate separated by a tiny gap, a design that limits membrane motion and caps dynamic range. Optical MEMS technology removes the backplate and instead measures diaphragm movement using laser interferometry. Inside each SBM100B, a vertical-cavity surface-emitting laser, diffractive optical element, and photodetector convert minute diaphragm motions directly into a digital audio signal. This architecture enables up to 20 times greater membrane movement, delivering an 80dB signal-to-noise ratio, a 146dB SPL acoustic overload point, and 132dB dynamic range—performance on par with handheld studio condenser microphones despite a dramatically smaller form factor. Such precision, combined with digital output and robust matching between elements, is especially critical in dense ambisonics arrays where small magnitude or phase mismatches can degrade beamforming accuracy.
Performance Gains and Manufacturing Advantages for Spatial Audio Capture
By integrating the SBM100B, mh acoustics reports an 8dB improvement in signal-to-noise ratio and a 16dB increase in acoustic overload point compared with the previous electret-based Eigenmike. This means the em64d can faithfully capture extremely quiet ambiences and very loud soundscapes within a single session, which is essential for demanding spatial audio capture scenarios such as orchestral recording, live events, or complex environmental soundscapes. Beyond raw performance, optical MEMS technology brings manufacturing benefits: surface-mount compatibility, reflow soldering, tight unit-to-unit matching, and long-term stability simplify assembly and calibration of large arrays. For a 64-channel ambisonics microphone, consistency across capsules directly translates into cleaner beamforming, more accurate high-order encoding, and shorter production lead times. These advantages collectively push the Eigenmike microphone from a boutique, hand-calibrated tool toward a more scalable platform ready for broader professional deployment.
Democratizing High-Order Ambisonics for Creators and Researchers
The combination of optical MEMS technology and an integrated software ecosystem positions the em64d Eigenmike as a catalyst for democratizing advanced spatial audio. With studio-grade capsule performance, sixth-order ambisonics, and turnkey tools for beamforming and multichannel recording, complex 360 degree recording workflows become more accessible to audio engineers, researchers, and ambitious enthusiasts. Creators can capture natural soundfields—such as forests, cityscapes, or concert halls—and reproduce them as immersive, navigable experiences for VR, AR, or next-generation streaming platforms. Researchers gain a precise instrument for acoustic measurements and soundfield analysis, while post-production teams benefit from flexible virtual mic steering and format-agnostic spatial rendering. Although still a specialized device, the em64d exemplifies how optical MEMS microphones can shrink studio-class performance into compact, reproducible hardware. As these components proliferate, they are likely to underpin a new generation of ambisonics microphones and spatial audio tools, gradually bringing high-order 3D sound within reach of a much wider community.
