Calibration method for Brahma microphones was developed in collaboration with Prof Angelo Farina and his team at the University of Parma. He has measured the prototypes at an anechoic chamber before developing the processes we are using, and has compared the results. This is an ongoing collaboration and future designs will also be submitted to Parma for evaluation.
The process of calibration generates a set of 2d and 3d graphics of the frequency response and directional properties of the four synthesised microphones. Errors in calibration are caught at this stage. If there are errors in these graphics the microphone is calibrated again.
Of the currently produced Ambisonic microphones, only CoreSound Tetramic and Brahma provide these calibration files. Several big name microphones are providing microphones without individual calibration, even when it has been clearly shown to be an unsatisfactory method.