Chalikia M H, Bregman A S
Percept Psychophys. 1989 Nov;46(5):487-96. doi: 10.3758/bf03210865.
In the experiments reported here, we attempted to find out more about how the auditory system is able to separate two simultaneous harmonic sounds. Previous research (Halikia & Bregman, 1984a, 1984b; Scheffers, 1983a) had indicated that a difference in fundamental frequency (F0) between two simultaneous vowel sounds improves their separate identification. In the present experiments, we looked at the effect of F0s that changed as a function of time. In Experiment 1, pairs of unfiltered or filtered pulse trains were used. Some were steady-state, and others had gliding F0s; different F0 separations were also used. The subjects had to indicate whether they had heard one or two sounds. The results showed that increased F0 differences and gliding F0s facilitated the perceptual separation of simultaneous sounds. In Experiments 2 and 3, simultaneous synthesized vowels were used on frequency contours that were steady-state, gliding in parallel (parallel glides), or gliding in opposite directions (crossing glides). The results showed that crossing glides led to significantly better vowel identification than did steady-state F0s. Also, in certain cases, crossing glides were more effective than parallel glides. The superior effect of the crossing glides could be due to the common frequency modulation of the harmonics within each component of the vowel pair and the consequent decorrelation of the harmonics between the two simultaneous vowels.
在本文所报告的实验中，我们试图进一步了解听觉系统是如何分离两个同时出现的谐波声音的。先前的研究（哈利基娅和布雷格曼，1984年a篇、1984年b篇；谢弗斯，1983年a篇）表明，两个同时出现的元音声音之间的基频（F0）差异有助于提高对它们的分别识别。在本实验中，我们研究了随时间变化的F0的影响。在实验1中，使用了成对的未滤波或滤波后的脉冲序列。一些是稳态的，另一些具有滑动的F0；还使用了不同的F0间隔。受试者必须指出他们听到了一个还是两个声音。结果表明，F0差异的增加和滑动的F0有助于同时出现的声音的感知分离。在实验2和3中，在稳态、平行滑动（平行滑音）或相反方向滑动（交叉滑音）的频率轮廓上使用了同时合成的元音。结果表明，交叉滑音比稳态F0能带来显著更好的元音识别效果。此外，在某些情况下，交叉滑音比平行滑音更有效。交叉滑音的优越效果可能是由于元音对每个成分内谐波的共同频率调制以及两个同时出现的元音之间谐波的去相关作用。
