the device can also record stereo audio using the two microphones mounted on the two earcups. having microphones so close to where one's ears would be gives the sound a lot of presence. the componnts are mounted on a pair of headphones that i've had for around five years now and the whole assembly is modular, meaning that faulty components can be easily swapped out.
sonic uses twin i2s mems microphones( SPH0645) for audio recording and a accelerometer+gyroscope+magnetometer(LSM9DS1) ic for head-tracking.