Intelligibility of speech in noise under diotic and dichotic binaural listening

Binaural sound reproduction (BSR) can improve speech intelligibility due to spatial release from masking (SRM), in the case where the signals are reproduced in such a manner that they are perceived as arriving to the listener from different directions. However, the effect of BSR on speech intelligibility has not yet been thoroughly studied for different noise conditions that involve diotic or binaural playback via headphones. In this work, a hearing in noise test (HINT) is performed, in which both the target and the noise are presented over headphones, in order to compare the speech intelligibility in the following conditions: (1) target and noise signals are displayed as diotic signals, (2) target is binaurally reproduced and noise is diotic, (3) target is diotic and noise is binaurally reproduced, and (4) target and noise signals are binaurally reproduced at the same direction. The results show that the speech intelligibility is significantly better in condition 2 relative to the other conditions.