Application of different types of microphones in room impulse response measurements

The features of the acoustic field in a room are generally described using omnidirectional and spatial parameters. Those are determined from the recorded Room Impulse Responses (RIR). Standardized RIR recording methods are described in ISO 3382 and require three different types of microphones. An omnidirectional microphone to determine the RIR at a given point in the room and bidirectional or binaural microphone to get RIRs containing the spatial properties of the acoustic field. Instead, popular but not standardized ambisonic technology makes it possible to measure a Spatial Room Impulse Response (SRIR). Signal processing technology lets to obtain omnidirectional and binaural RIRs from an SRIR. In this study, RIRs were recorded using the following types of microphones: omnidirectional, binaural (2 different types of acoustic manikin) and ambisonic (first and third order). Presented results show the comparison of room acoustic parameters calculated from RIRs measured with different microphone techniques. The results show ambisonic technology’s usefulness in assessing room acoustic parameters.