Ishigami H, Suzuki T, Isojima G
Department of Otorhinolaryngology, Aichi Medical University, Japan.
Auris Nasus Larynx. 1995;22(1):7-15. doi: 10.1016/s0385-8146(12)80176-3.
In Experiment I, band noises were used as signals and pure tones were used as maskers. The conventional psychophysical tuning curves (PTCs) present the following characteristics depending on the signal level; slopes of the PTC are steeper than those of the auditory nerve fibers frequency threshold curve (FTC). This result from the large effect of the combination tones and, especially, of the off-frequency listening. Bandwidths of PTC do not depend on both signal levels and duration, but they are narrower than the equivalent rectangular bandwidth (ERB) of auditory filters. Masked thresholds at tips of PTC are affected by the temporal integration of signal sound at signal levels of 10- and 20-dB SL, but are not affected at 30-dB SL. This implies a close relation between PTCs and critical bandwidths (CB-widths). In Experiment II, pure tones were used as signals and band noise were used as maskers. The low- and high-frequency slopes were steeper in Experiment I. The flat parts of the masked threshold at the tips of curves become broader as the signal duration increased. No such flattening was found at a 30-dB signal level, irrespective of signal duration. The results of Experiment II coincide with the prediction derived from the excitation-pattern model. Masked thresholds at the tip of PTC were the same as in Experiment I. The conventional PTC represents the psychological frequency selectivity, and its 3-dB bandwidth corresponds to the CB-width. However, the quantitative properties depend greatly upon the bandwidths of the band noises used as signals or maskers.
在实验一中，将带噪作为信号，纯音作为掩蔽音。传统的心理物理调谐曲线（PTC）根据信号水平呈现出以下特征：PTC的斜率比听神经纤维频率阈值曲线（FTC）的斜率更陡。这是由于组合音尤其是偏离频率聆听的巨大影响所致。PTC的带宽既不取决于信号水平也不取决于持续时间，但它们比听觉滤波器的等效矩形带宽（ERB）更窄。在10 dB SL和20 dB SL的信号水平下，PTC峰值处的掩蔽阈值受信号音的时间整合影响，但在30 dB SL时不受影响。这意味着PTC与临界带宽（CB宽度）之间存在密切关系。在实验二中，将纯音用作信号，带噪用作掩蔽音。实验一中低频和高频斜率更陡。随着信号持续时间增加，曲线峰值处掩蔽阈值的平坦部分变宽。在30 dB信号水平下，无论信号持续时间如何，均未发现这种平坦化现象。实验二的结果与从兴奋模式模型得出的预测相符。PTC峰值处的掩蔽阈值与实验一相同。传统的PTC代表心理频率选择性，其3 dB带宽对应于CB宽度。然而，定量特性在很大程度上取决于用作信号或掩蔽音的带噪的带宽。
