Lyzenga J, Horst J W
Department of Otorhinolaryngology/Audiology, University Hospital Groningen, The Netherlands.
J Acoust Soc Am. 1998 Nov;104(5):2956-66. doi: 10.1121/1.423878.
Just-noticeable differences (jnd's) in the formant frequencies of synthetic two-formant "vowels" were measured for normal hearing subjects. The jnd's were examined for a change in only the first or the second formant, and for a combined change of both formants. For the combined change two quantitative relations between the formant frequencies were used; one with equal relative changes in both formants, and one with a double relative change for the first formant. Formant frequencies were 500, 550, and 600 Hz in the first, and 2000, 2050, and 2100 Hz in the second formant region. Both formants had either shallow or steep slopes. For the fundamental frequency of the complexes we used 100 and 200 Hz. For the single-formant changes, a "natural," and a random-phase relation were used between the individual components of the complexes. These results were compared to jnd's for a Gaussian noise that was filtered with the same spectral envelopes as the harmonic complexes. For the combined formant changes only the natural phase relation was used. A three-interval, three-alternative forced-choice task was used. All measurements were performed with roving stimulus level. For the single formant changes, the phase relations had no effect on the results. For the harmonic stimuli, jnd's were mostly smaller for the formants between two harmonics than for those at a harmonic. The results for the harmonic stimuli as well as the noise bands could be described by a model using a spectral profile comparison. For the combined formant changes smaller jnd's were found than for the single changes. These jnd's could be explained by combining measures of the perceived differences from the two separately changed formants. In this combination these measures were summed as independent variables.
我们测量了正常听力受试者对合成双共振峰“元音”共振峰频率的恰可察觉差异（jnd）。研究了仅第一或第二共振峰变化以及两个共振峰同时变化时的jnd。对于两个共振峰同时变化的情况，使用了共振峰频率之间的两种定量关系；一种是两个共振峰的相对变化相等，另一种是第一共振峰的相对变化加倍。第一共振峰区域的共振峰频率为500、550和600赫兹，第二共振峰区域为2000、2050和2100赫兹。两个共振峰都有浅斜率或陡斜率。对于复合音的基频，我们使用了100和200赫兹。对于单共振峰变化，复合音的各个成分之间采用了“自然”和随机相位关系。将这些结果与用与谐波复合音相同频谱包络滤波的高斯噪声的jnd进行比较。对于共振峰联合变化，仅使用自然相位关系。采用了三区间、三择一的强迫选择任务。所有测量均在可变刺激水平下进行。对于单共振峰变化，相位关系对结果没有影响。对于谐波刺激，两个谐波之间的共振峰的jnd大多比谐波处的共振峰的jnd小。谐波刺激以及噪声带的结果可以用一个使用频谱轮廓比较的模型来描述。对于共振峰联合变化，发现其jnd比单共振峰变化时小。这些jnd可以通过结合两个分别变化的共振峰的感知差异测量值来解释。在这种组合中，这些测量值作为独立变量相加。
