Modifying the Directional Responses of a Coincident Pair of Microphones by Postprocessing*

The proposed technique processes coincident or nearly coincident microphone stereo recordings to change the angle between and the width of the directional responses of the microphones effectively. Through this modification of the responses the width and spaciousness of the stereo recording can be controlled without introducing any artificial reverberation into the recording. The algorithm is based on prediction with the aim of controlling the amount of sound corresponding to the overlapping part of the microphone responses. It is shown how this processing relates to the effective directional responses of the processed signals. The results of a headphone-based subjective test indicate that the achieved audio waveform quality is very high and B-format derived coincident cardioid stereo recordings are improved significantly.