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Published in Stanley A. Gelfand, Hearing, 2017
Figure 10.8 indicates that the critical band becomes wider as the center frequency increases. Scharf (1970) has provided a table of critical bandwidth estimates based upon the available data. Examples are a critical bandwidth of 100 Hz for a center frequency of 250 Hz, a 160-Hz band for 1000 Hz, and a 700-Hz band for 4000 Hz. Similar data and formulas for calculation of the critical bandwidth and critical band rate (the bark scale) have been provided by Zwicker and Terhardt (1980). Actually, one should be careful not to conceive of a series of discrete critical bands laid, as it were, end to end, but rather of a bandwidth around any particular frequency that defines the phenomenon we have discussed with respect to that frequency. (One should remember in this context Scharf's [1970, p. 159] elegant definition: “the critical band is that bandwidth at which subjective responses rather abruptly change.”) We should thus think of critical bandwidths as overlapping filters rather than as discrete, contiguous filters.
Sound discrimination and explicit mapping of sounds to meanings in preschoolers with and without developmental language disorder
Published in International Journal of Speech-Language Pathology, 2021
Carolyn Quam, Holly Cardinal, Celeste Gallegos, Todd Bodner
Sound categories were defined by either pitch or duration variation. Two categories were defined along each dimension: low pitch vs. high pitch, or short duration vs. long duration. Each category contained only three distinct sounds, making six sounds total per dimension. Figure 1 displays pitch and duration values for all stimuli. Pitch stimuli were spaced according to the Bark scale (which incorporates logarithmic compression to simulate high-frequency compression in the human auditory system; Zwicker, 1961). Pilot testing indicated that children were more sensitive to pitch than duration. We therefore compressed differences among duration stimuli within-category and increased the distance between categories, in an attempt to make the duration categories more differentiable. The second-formant frequency was set to mimic an /u/ vowel for the pitch-differentiated sounds (1254 Hertz, or 8.9 Barks) and an /i/ vowel for the duration-differentiated sounds (2988 Hertz, or 13.9 Barks). For all sounds, the first, third, fourth, and fifth formant frequencies were set to 448, 2722, 4019, and 4898 Hertz, respectively (corresponding to 4.1, 13.3, 15.6, and 16.8 Barks).