Noise thresholds in harmonic series maskers

The presence of noise is a salient cue to the perception of breathiness and aspiration in speech sounds. The detection of noise within harmonic series (maskers) composed of unresolved components was found to depend on the fundamental frequency (f_o) and the overall level of the masker [Gockel, Moore, and Patterson (2002). J. Acoust. Soc. Am., 111 (6), 2759-2770]. In the present study, noise detection thresholds were measured as a function of the frequency range, the f_o, and the overall level of harmonic maskers. Frequency range was specified in equivalent rectangular bandwidth (ERB) units (3-13, 13-23, 23-33, or 3-33 ERBs). The results were consistent with the idea that listeners rely on spectral cues when maskers comprise only resolved components (3-13 ERBs), and on temporal (dip listening) cues when maskers contain only unresolved components (23-33 ERBs). Noise detection thresholds were generally lower when masker level was high (70 dBA) than when it was low (50 dBA). Masker f_o affected thresholds only when listeners relied on spectral cues for noise detection. With the wideband (3-33 ERBs) masker, listeners likely detected noise by focusing on the frequency band (23-33 ERBs) with the most advantageous noise-to-harmonic ratio.