A PCC (Phase Coherent Cardiod) microphone is a boundary microphone that uses a cardioid element mounted perpendicular to the boundary surface. By keeping the element very small and located very close to the boundary surface, the resulting interference from reflections also occurs at very high frequencies. This same general concept is often applied when measuring loudspeakers or speaker systems, the measurement mic is place very near a large reflecting boundary surface in order to minimize the effect of 'ground bounce' and push the resulting interaction up to frequencies above those being measured.
See http://www.crownaudio.com/mic_web/pcc.htm and/or http://www.bartlettmics.com/ .
See http://www.crownaudio.com/mic_web/pcc.htm and/or http://www.bartlettmics.com/ .
