OCT-3D Modular is a professional microphone system for 9-channel immersive audio recording in 5.1.4 format (compatible with Dolby Atmos and Auro-3D). This vertically coincident configuration extends OCT surround technology with four height channels, delivering natural spatial imaging with high channel separation and decorrelation in diffuse fields. The system comprises six CCM 41 L Supercardioid and three CCM 4 L Cardioid microphones mounted on MAB 1000 stereo bars with height channel riders, providing balanced surround imaging and superior direct signal suppression. Designed for studio applications requiring precise spatial audio capture, it maintains high stability while minimizing correlation between vertical microphone pairs through optional STR 250 support rods.