Intelligibility comparison of Japanese speech with competing noise spatialized in real and virtual acoustic environments

Abstract

We investigated the effect of a competing noise source on the intelligibility of target speech in various acoustic environments. To spatialize these sources in virtual acoustic space, we used head-related transfer functions (HRTFs) measured using the KEMAR dummy head, as well as HRTFs measured individually for each subject. We also compared the intelligibility when these sound sources were generated from loudspeakers located at the target and competing source positions in real acoustic space. The speech intelligibility of the target speech was evaluated using the Japanese diagnostic rhyme test (DRT). The target speech was placed directly in front of the listener, and a single competing source was placed on the same horizontal plane at various azimuths and distances. Individual HRTFs showed slightly better intelligibility than those with KEMAR HRTFs, but the difference was small in most cases. Intelligibility in real acoustic space still outperformed both types of HRTFs, especially when the competing sound source was closer to the listener than the target speech and the competing source was located at 180°. However, this difference was small in most of the other competing source locations tested.