Speech reception thresholds in various interference conditions
Suzanne P. Carr, H. Steven Colburn · The Journal of the Acoustical Society of America · 2004
Speech intelligibility is integral to human verbal communication; however, our understanding of the effects of competing noise, room reverberation, and frequency range restriction is incomplete. Using virtual stimuli, the dependence of intelligibility threshold levels on the extent of room reverberation, the relative locations of speech target and masking noise, and the available frequency content of the speech and the masking noise is explored. Speech-shaped masking noise and target sentences have three spectral conditions: wideband, high pass above 2-kHz, and low pass below 2-kHz. The 2-kHz cutoff was chosen to approximately bisect the range of frequencies most important in speech, and the high pass noise condition simulates high-frequency hearing loss. Reverberation conditions include a pseudo-anechoic case, a moderately reverberant ‘‘classroom’’ case, and a very reverberant ‘‘bathroom’’ case. Both binaural and monaural intelligibility are measured. Preliminary results show that source separation decreases thresholds, reverberation increases thresholds, and low frequency noise reverberates more in the rooms, contributing to increasing thresholds along with the effects of the upward spread of masking. The energetic effects of reverberation are explored. [Work supported by NIH DC00100.]