Influence of not-linearity in the uncertainty on room acoustics measurements

Room acoustics measurements are influenced by many factors, as the typology of devices, the directivity of loudspeakers, the orientation of microphones, the position of sound sources, the frequency response of both microphones and loudspeakers, and so on. Recently, after an inter-University round robin test on room acoustics measurements, very wide data dispersion was found, by changing equipment and post-processing software. Moreover, some acoustic parameters related with sound spatialisation, as IACC and IACF, resulted quite sensitive to electronic devices, and therefore widely spread out. In this paper the uncertainties on room acoustics measurements has been analysed starting from a different approach. Measurements of binaural and B-Format Impulse Responses (by means of the Neumann dummy head, the SoundField MKV microphone and an omnidirectional pre-equalised loudspeaker) have been obtained in a room at University of Bologna. The acoustical parameters obtained after post-processing the BIRs and B-Format IRs have been compared with acoustic distortion in electronic devices. A strong correlation between some acoustical parameters (especially IACC and IACF) and sound distortion was found. The correlation has underlined a high sensitivity on spatial sound distribution due to electronic distortion.