From Stereo to Spherical: Why Ambisonics Needs Better Microphones
Ambisonics microphone recording captures a full 360 degree spatial audio soundfield, going far beyond traditional stereo techniques. Instead of two channels aimed left and right, higher-order ambisonics arrays like mh acoustics’ Eigenmike sample sound pressure from dozens of directions on a sphere. This enables precise localization, realistic immersive audio production, and advanced acoustic measurements that stereo simply cannot offer. Engineers can beamform to isolate sound sources, analyze reflections, and recreate convincing three-dimensional soundscapes for VR, cinema, or research. However, the quality of these results depends heavily on the consistency and performance of every capsule in the array. Any mismatch in noise, sensitivity, or phase between microphones can degrade spatial accuracy. That is why the move to new MEMS microphone technology is so significant: it aims to deliver the uniform, wide dynamic range performance ambisonics systems have long been waiting for.
Inside the em64d Eigenmike: A Sixth-Order Ambisonics Powerhouse
The new Eigenmike em64d from mh acoustics is a sixth-order ambisonics microphone array built around 64 tightly matched elements arranged on an 84 mm rigid sphere. Retaining the familiar geometry of the previous em64, the latest generation adds deeper refinements under the hood. The array offers a 20 Hz–20 kHz frequency response, 48 kHz sampling, and a spatial aliasing cutoff above 12 kHz, supporting detailed capture of complex soundfields. On the software side, the em64d ships with eigenStudio for control, recording, and visualization, plus EigenUnit VST plugins for post-production workflows. Together, the hardware and software form a complete, high-order ambisonics solution in a single platform. Whether used for ambisonics microphone recording on film sets, in concert halls, or in experimental labs, the em64d is designed to deliver high-resolution 360 degree spatial audio with precise beamforming and flexible multitrack exports.
Optical MEMS: How sensiBel’s SBM100B Breaks the Dynamic Range Barrier
At the heart of the Eigenmike em64d is sensiBel’s SBM100B, an optical MEMS microphone that rethinks transducer design. Instead of a capacitive structure with a perforated backplate, the SBM100B uses laser interferometry to measure diaphragm motion. A miniature VCSEL, diffractive optical element, and photodetector sit inside the package, translating diaphragm movement directly into a digital audio signal. Without the backplate, the diaphragm can move about 20 times more than in conventional capacitive MEMS microphones, unlocking major acoustic benefits. The SBM100B achieves an 80 dB signal-to-noise ratio, a 146 dB SPL acoustic overload point, and 132 dB dynamic range—performance comparable to studio condenser microphones that are dozens of times larger. This MEMS microphone technology solves the long-standing trade-off between miniaturization and audio quality, making it uniquely suited to high-density arrays where each channel must deliver low noise, high headroom, and excellent matching.
Why Optical MEMS Elevates the Next-Generation Eigenmike
Replacing 64 electret condenser capsules with 64 SBM100B optical MEMS microphones gives the Eigenmike em64d a substantial performance and manufacturing upgrade. System-level, mh acoustics reports roughly 8 dB higher SNR and 16 dB higher AOP than its previous ECM-based design, improving capture quality in both extremely quiet and very loud environments. Just as important for ambisonics is capsule consistency: higher-order processing is highly sensitive to small magnitude and phase variations between microphones. MEMS fabrication and surface-mount integration help deliver the tight matching, reflow compatibility, and long-term stability needed for reliable, repeatable spatial performance. Production becomes faster and less complex, with shorter lead times for customers. The result is an ambisonics microphone recording platform that is not only more robust in the field, but also more scalable to produce—an essential step for broader adoption of advanced 360 degree spatial audio tools.
New Frontiers: Immersive Audio and Precision Acoustic Measurement
With optical MEMS at its core, the Eigenmike em64d positions itself as a tool for both creative and scientific work. For immersive audio production, its sixth-order ambisonics capability supports ultra-precise rendering for VR, games, and spatial music, allowing mixers to place listeners inside believable 3D environments. Field recordists can document entire soundscapes—such as dense forest ecosystems or bustling urban spaces—with lifelike envelopment and directional detail. In technical domains, the array’s studio-quality performance and high dynamic range make it suitable for precision acoustic analysis, room characterization, and beamforming research. Engineers can compute sharply focused directional patterns, inspect reflections and diffuse fields, and run complex soundfield simulations using real measurements. As ambisonics microphone recording moves further into mainstream workflows, the combination of sensiBel’s optical MEMS microphone technology and mh acoustics’ Eigenmike platform points toward more accurate, accessible 360 degree spatial audio capture.
