Moore B C, Oldfield S R, Dooley G J
Department of Experimental Psychology, University of Cambridge, England.
J Acoust Soc Am. 1989 Feb;85(2):820-36. doi: 10.1121/1.397554.
The ability of subjects to detect and discriminate spectral peaks and notches in noise stimuli was determined for center frequencies fc of 1 and 8 kHz. The signals were delivered using an insert earphone designed to produce a flat frequency response at the eardrum for frequencies up to 14 kHz. In experiment I, subjects were required to distinguish a broadband reference noise with a flat spectrum from a noise with either a peak or a notch at fc. The threshold peak height or notch depth was determined as a function of bandwidth of the peak or notch (0.125, 0.25, or 0.5 times fc). Thresholds increased with decreasing bandwidth, particularly for the notches. In experiment II, subjects were required to detect an increase in the height of a spectral peak or a decrease in the depth of a notch as a function of bandwidth. Performance was worse for notches than for peaks, particularly at narrow bandwidths. For both experiments I and II, randomizing (roving) the overall level of the stimuli had little effect at 1 kHz, but tended to impair performance at 8 kHz, particularly for notches. Experiments III-VI measured thresholds for detecting changes in center frequency of sinusoids, bands of noise, and spectral peaks or notches in a broadband background. Thresholds were lowest for the sinusoids and highest for the peaks and notches. The width of the bands, peaks, or notches had only a small effect on thresholds. For the notches at 8 kHz, thresholds for detecting glides in center frequency were lower than thresholds for detecting a difference in center frequency between two steady sounds. Randomizing the overall level of the stimuli made frequency discrimination of the sinusoids worse, but had little or no effect for the noise stimuli. In all six experiments, performance was generally worse at 8 kHz than at 1 kHz. The results are discussed in terms of their implications for the detectability of spectral cues introduced by the pinnae.
针对1千赫和8千赫的中心频率fc，测定了受试者检测和区分噪声刺激中频谱峰值和凹口的能力。信号通过一款插入式耳机传递，该耳机设计用于在鼓膜处产生高达14千赫频率的平坦频率响应。在实验I中，要求受试者区分具有平坦频谱的宽带参考噪声与在fc处有峰值或凹口的噪声。阈值峰值高度或凹口深度被确定为峰值或凹口带宽（0.125、0.25或0.5倍fc）的函数。阈值随带宽减小而增加，特别是对于凹口。在实验II中，要求受试者检测频谱峰值高度的增加或凹口深度的减小作为带宽的函数。凹口的表现比峰值差，特别是在窄带宽时。对于实验I和II，随机化（移动）刺激的总体水平在1千赫时影响很小，但在8千赫时往往会损害表现，特别是对于凹口。实验III - VI测量了检测正弦波、噪声带以及宽带背景中频谱峰值或凹口的中心频率变化的阈值。正弦波的阈值最低，峰值和凹口的阈值最高。带、峰值或凹口的宽度对阈值只有很小的影响。对于8千赫的凹口，检测中心频率滑动的阈值低于检测两个稳定声音之间中心频率差异的阈值。随机化刺激的总体水平使正弦波的频率辨别变差，但对噪声刺激影响很小或没有影响。在所有六个实验中，8千赫时的表现通常比1千赫时差。根据这些结果对耳廓引入的频谱线索的可检测性的影响进行了讨论。
