Differences in speech intelligibility in noise measured under spatial sound reproduction implemented with varying recording and rendering techniques

The current paper studies the differences in speech intelligibility in noise measured under reproduced acoustic environments implemented using different recording and rendering techniques. Acoustics of two rooms with different volume and reverberation time were reproduced by spherical harmonics-based spatial sound reproduction and the speech intelligibility under reproduced acoustic environments were compared to that in the original rooms by conducting subjective listening tests. Four implementations of spatial sound reproduction realised by the combinations of two recording techniques (using first and higher order Ambisonics microphones) and two rendering techniques (using a headphone and loudspeaker array) were evaluated. The experimental results found the speech intelligibility under reproduced acoustic environments implemented by using either a first- or higher-order Ambisonics microphone and a 32-ch loudspeaker array achieved to replicate results not significantly different from that observed in the original real rooms when the room is highly reverberant. The same implementation with the higher-order Ambisonics microphone also most accurately replicated the effect of angular separation between the speech and noise sources as well as source distance on the speech intelligibility. The results also suggest that the technique used for rendering would have larger effect on reproducibility of speech intelligibility in the real room than the recording technique whereas the technique used for recording would have larger effect on reproducibility of the effect of angular separation between speech and noise sources in the real room.