Talker head-orientation and extended high-frequency benefits for speech recognition as a function of masker head angle

Several types of cues contribute to speech recognition in multi-talker environments. In this study, we investigated how talker head-orientation related (THOR) cues and extended high- frequency (EHF; >8kHz) cues affect speech-in-speech recognition for both female and male speech. We examined the THOR benefit associated with a non-facing masker talker head orientation (relative to a facing orientation) as a function of masker talker facing angle. The target talker always faced the listener, whereas co-located maskers were tested with eight different masker head angles, ranging from 0° (facing the listener) to facing 180° away. Two filtering conditions were tested: full- band and low-pass filtered at 8 kHz. A THOR benefit was observed at masker head angles greater than 45°, increasing from 2 dB to 8 dB between angles of 67.5° and 180°. This benefit was reduced for low-pass filtered speech. Access to EHF cues improved performance, but only for masker head angles >22.5°. There was no significant relationship between 16-kHz pure-tone thresholds and performance for young, normal-hearing listeners with good EHF hearing. These findings indicate that listeners benefit from non-facing masker talker head orientations >45° when the target talker is facing the listener, with greater benefit for larger head angles.