Cues above 4 kilohertz can improve spatially separated speech recognition.

Abstract

There are multiple acoustic cues above 4 kHz that may be used to improve speech recognition in noisy environments. This study tests this hypothesis with spatially separated speech maskers. The reception threshold of speech (RTS) was measured in two conditions: (1) asymmetric condition with target speech at −45° and maskers at +45°, and (2) diffuse condition with speech at 0° and one masker at each of four quadrants around the listener (±45°, ±135°). HINT sentences were rerecorded using a male talker and a 22.05 kHz bandwidth while different males were recorded speaking the television and rainbow as maskers. SRTs were measured with all materials low‐pass filtered at 4, 6, 8, and 10 kHz for the asymmetric and diffuse conditions. 12 normal hearing subjects (on the way to 24) were tested using free‐field loudspeakers in a sound booth. The mean RTSs for the asymmetric condition were −17.43, −19.07, −19.34, and −20.65 dB for 4, 6, 8, and 10 kHz, respectively. For the diffuse condition the mean RTSs were −7.77, −9.00, −9.88, and −10.05 dB for the same frequencies. The results suggest that high‐frequency acoustic cues can enhance the ability to segregate spatially separated speech.