The effect of noise fluctuation and spectral bandwidth on gap detection.
Experiment 1 investigated gap detection for random and low-fluctuation noise (LFN) markers as a function of bandwidth (25-1600 Hz), level [40 or 75 dB sound pressure level (SPL)], and center frequency (500-4000 Hz). Gap thresholds for random noise improved as bandwidth increased from 25 to 1600 Hz, but there were only minor effects related to center frequency and level. For narrow bandwidths, thresholds were lower for LFN than random markers; this difference extended to higher bandwidths at the higher center frequencies and was particularly large at high stimulus level. Effects of frequency and level were broadly consistent with the idea that peripheral filtering can increase fluctuation in the encoded LFN stimulus. Experiment 2 tested gap detection for 200-Hz-wide noise bands centered on 2000 Hz, using high-pass maskers to examine spread of excitation effects. Such effects were absent or minor for random noise markers and the 40-dB-SPL LFN markers. In contrast, some high-pass maskers substantially worsened performance for the 75-dB-SPL LFN markers. These results were consistent with an interpretation that relatively acute gap detection for the high-level LFN gap markers resulted from spread of excitation to higher-frequency auditory filters where the magnitude and phase characteristics of the LFN stimuli are better preserved.
Department of Otolaryngology-Head & Neck Surgery, University of North Carolina at Chapel Hill, 170 Manning Drive, Chapel Hill, North Carolina 27599-7070, USA.
Joseph W
JW
Hall
Department of Otolaryngology-Head & Neck Surgery, University of North Carolina at Chapel Hill, 170 Manning Drive, Chapel Hill, North Carolina 27599-7070, USA.
Emily
E
Buss
Department of Communication Sciences and Disorders, University of South Florida, Tampa, Florida 33620, USA.
Erol J
EJ
Ozmeral
Department of Otolaryngology-Head & Neck Surgery, University of North Carolina at Chapel Hill, 170 Manning Drive, Chapel Hill, North Carolina 27599-7070, USA.
John H
JH
Grose
D000161:Acoustic Stimulation; D000162:Acoustics; D001301:Audiometry, Pure-Tone; D001307:Auditory Perception; D001309:Auditory Threshold; D006801:Humans; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D011312:Pressure; D017603:Signal Detection, Psychological; D013018:Sound Spectrography