Marin C M, McAdams S
Institut de Recherche et Coordination Acoustique/Musique (IRCAM), Paris, France.
J Acoust Soc Am. 1991 Jan;89(1):341-51. doi: 10.1121/1.400469.
The research presented here concerns the simultaneous grouping of the components of a vocal sound source. McAdams [J. Acoust. Soc. Am. 86, 2148-2159 (1989)] found that when three simultaneous vowels at different pitches were presented with subaudio frequency modulation, subjects judged them as being more prominent than when no vibrato was present. In a normal voice, when the harmonics of a vowel undergo frequency modulation they also undergo an amplitude modulation that traces the spectral envelope. Hypothetically, this spectral tracing could be one of the criteria used by the ear to group components of each vowel, which may help explain the lack of effect of frequency modulation coherence among different vowels in the previous study. In this experiment, two types of vowel synthesis were used in which the component amplitudes of each vowel either remained constant with frequency modulation or traced the spectral envelope. The stimuli for the experiment were chords of three different vowels at pitch intervals of five semitones (ratio 1.33). All the vowels of a given stimulus were produced by the same synthesis method. The subjects' task involved rating the prominence of each vowel in the stimulus. It was assumed that subjects would judge this prominence to be lower when they were not able to distinguish the vowel from the background sound. Also included as stimulus parameters were the different permutations of the three vowels at three pitches and a number of modulation conditions in which vowels were unmodulated, modulated alone, and modulated either coherently with, or independently of, the other vowels. Spectral tracing did not result in increased ratings of vowel prominence compared to stimuli where no spectral tracing was present. It would therefore seem that it has no effect on grouping components of sound sources. Modulated vowels received higher prominence ratings than unmodulated vowels. Vowels modulated alone were judged to be more prominent than vowels modulated with other vowels. There was, however, no significant difference between coherent and independent modulation of the three vowels. Differences among modulation conditions were more marked when the modulation width was 6% than when it was 3%.
此处呈现的研究涉及语音声源成分的同时分组。麦克亚当斯[《美国声学学会杂志》86, 2148 - 2159 (1989)]发现，当以亚音频调制呈现三个不同音高的同时发声的元音时，与无颤音情况相比，受试者判断它们更突出。在正常语音中，当元音的谐波进行频率调制时，它们也会经历追踪频谱包络的幅度调制。据推测，这种频谱追踪可能是耳朵用于对每个元音成分进行分组的标准之一，这可能有助于解释先前研究中不同元音之间频率调制连贯性缺乏效果的原因。在本实验中，使用了两种类型的元音合成，其中每个元音的成分幅度要么在频率调制时保持恒定，要么追踪频谱包络。实验刺激是由三个不同元音组成的和弦，音高间隔为五个半音（比例1.33）。给定刺激中的所有元音均通过相同的合成方法产生。受试者的任务是对刺激中每个元音的突出程度进行评分。假设当受试者无法将元音与背景声音区分开时，他们会判断这种突出程度较低。作为刺激参数还包括三个元音在三个音高上的不同排列以及一些调制条件，其中元音未调制、单独调制，以及与其他元音相干或独立调制。与不存在频谱追踪的刺激相比，频谱追踪并未导致元音突出程度评分增加。因此，似乎它对声源成分的分组没有影响。调制元音的突出程度评分高于未调制元音。单独调制的元音被判断比与其他元音一起调制的元音更突出。然而，三个元音的相干调制和独立调制之间没有显著差异。当调制宽度为6%时，调制条件之间的差异比为3%时更为明显。
