Practical implementation and analysis of spatial soundfield capture by higher order microphones

Abstract

Spatial soundfield recording is important for capturing immersive audio environments, providing real spatial soundfields for soundfield reproduction and to test the quality of soundfield reproduction by loudspeakers. Recently, higher order microphones were introduced for spatial sound capture over large areas and proven by theoretical simulations. Higher order microphones have the advantage of requiring a lower number of units than ordinary microphones for capturing spatial soundfields over a region but are more complex. In this work, we implement a 2D higher order microphone system using ordinary microphones, amplifiers and audio interfaces. A soundfield is created with loudspeakers placed in the farfield of the microphones in a reverberant room. To capture the soundfield over a region, we recorded the soundfield on the boundary of this region using our higher order microphone system. These recording were processed to provide the soundfield pressure at all positions within this region and compared with actual recordings of the pressure at these position. Our results showed that the captured soundfield using the higher order microphone system had less than 10% error, proving its effectiveness for recording real soundfields and its implementation using available audio equipment.