Reply To: New Microphone Technologies

February 12, 2023 at 8:34 pm #4855
Len Moskowitz

    So what’s fundamentally different about spatial microphones?

    They capture and preserve everything going on acoustically at the point they are positioned. They record the entire soundfield.

    What you do with that very rich spatial recording later, in post-production, is up to you.

    You can decode it into a simple mono recording, with a single virtual microphone pointed in any direction you please, and with any directivity you want. It can have any polar pattern ranging along the first-order continuum from omnidirectional, to sub-cardioid, to cardioid, to super-cardioid, to hyper-cardioid, to figure-8. Or higher-order polar patterns that traditional mono mics can’t offer, including tighter polar patterns and smaller back and sidelobes than traditional mono shotgun microphones.

    Or you can decode the spatial recording to any number of coincident virtual microphones, each pointed in any direction, and having any polar pattern you want. You can select two crossed figure-8s for Blumlein and rotate the array to point in any direction. Or two cardioids for XY. Or three cardioids for LCR, and adjust the spacing angle. Or 5 cardioids or sub-cardioids for 5.1 playback. Or 7 of whatever polar patterns you want for 7.1. Or 11 for Atmos 7.1.4, including the four positioned above. Or three rings of 6 or 8 or 12 microphones for fully immersive playback. Or two omni microphones modified by personal HRTFs and driven by a headtracker for VR360 headset binaural playback. Or as a tight-pattern boom mic that automatically follows  a sound source moving in space.

    All of those options (and more) are available from a single spatial recording.

    All of those options are available in post-production.

    From a single high-resolution/high accuracy spatial recording.

    And the same range of options are available for spaced microphone arrays. So an ORTF-3D array that required 8 traditional mono microphones and compromises in the microphone spacing and angles, takes only four spatial microphones. The four spatial microphones provide exactly correct 110-degree angles and 17 cm spacings for all eight ORTF arrays, and each of the microphones acts as four virtual microphones.

    And it’s all selectable in post-production, offering flexibility unavailable with traditional mono microphones.