title: Frequency selectivity for frequencies below 100 Hz: comparisons with mid-frequencies.
abstract: Auditory filter shapes were derived for signal frequencies (f(s)) between 50 and 1000 Hz, using the notched-noise method. The masker spectrum level (N(0)) was 50 dB (re 20 μPa). For f(s) = 63 and 50 Hz, measurements were also made with N(0) = 62 dB for the lower band. The data were fitted using a rounded-exponential filter model, with special consideration of the filtering effects of the middle-ear transfer function (METF) at low frequencies. The results showed: (1) For very low values of f(s), the lower skirts of the filters were only well defined when N(0) = 62 dB for the lower band; (2) the sharpness of both sides of the filters decreased with decreasing f(s); (3) the dynamic range of the filters decreased with decreasing f(s); (4) the equivalent rectangular bandwidth of the filters decreased with decreasing f(s) down to f(s) = 80 Hz, but increased for f(s) below that; (5) the assumed METF, which includes the shunt effect of the helicotrema for frequencies below 50 Hz, increasingly influenced the low-frequency skirt of the filters as f(s) decreased; and (6) detection efficiency worsened with decreasing f(s) for f(s) between 100 and 500 Hz, but improved slightly below that.
authors.affiliation: Section of Acoustics, Department of Electronic Systems, Aalborg University, Fredrik Bajersvej 7-A, Denmark. cjo@es.aau.dk
authors.forename: Carlos
authors.initials: C
authors.lastname: Jurado
authors.forename: Brian C J
authors.initials: BC
authors.lastname: Moore
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001301:Audiometry, Pure-Tone; D001306:Auditory Pathways / Q000502:physiology*; D001309:Auditory Threshold; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D010470:Perceptual Masking; D010897:Pitch Discrimination; D017603:Signal Detection, Psychological; D013018:Sound Spectrography