School of Psychology, Aston University, Birmingham B4 7ET, United Kingdom.
J Acoust Soc Am. 2020 Oct;148(4):2416. doi: 10.1121/10.0002359.
The impact of an extraneous formant on intelligibility is affected by the extent (depth) of variation in its formant-frequency contour. Two experiments explored whether this impact also depends on masker spectro-temporal coherence, using a method ensuring that interference occurred only through informational masking. Targets were monaural three-formant analogues (F1+F2+F3) of natural sentences presented alone or accompanied by a contralateral competitor for F2 (F2C) that listeners must reject to optimize recognition. The standard F2C was created using the inverted F2 frequency contour and constant amplitude. Variants were derived by dividing F2C into abutting segments (100-200 ms, 10-ms rise/fall). Segments were presented either in the correct order (coherent) or in random order (incoherent), introducing abrupt discontinuities into the F2C frequency contour. F2C depth was also manipulated (0%, 50%, or 100%) prior to segmentation, and the frequency contour of each segment either remained time-varying or was set to constant at the geometric mean frequency of that segment. The extent to which F2C lowered keyword scores depended on segment type (frequency-varying vs constant) and depth, but not segment order. This outcome indicates that the impact on intelligibility depends critically on the overall amount of frequency variation in the competitor, but not its spectro-temporal coherence.
额外共振峰对可懂度的影响取决于其共振峰频率轮廓的变化程度（深度）。两个实验使用一种确保仅通过信息掩蔽产生干扰的方法，探索了这种影响是否也取决于掩蔽的频谱时间相干性。目标是单独呈现或伴随对 F2 的对侧竞争音（F2C）的单耳三共振峰模拟（F1+F2+F3），听众必须拒绝 F2C 以优化识别。标准 F2C 使用反转的 F2 频率轮廓和恒定幅度创建。变体通过将 F2C 划分为相邻的片段（100-200ms，10ms 上升/下降）来衍生。片段以正确的顺序（相干）或随机顺序（非相干）呈现，从而在 F2C 频率轮廓中引入突然的不连续性。在分割之前，F2C 的深度也被操纵（0%、50%或 100%），并且每个片段的频率轮廓要么保持时变，要么设置为该片段的几何平均频率的恒定。F2C 降低关键词得分的程度取决于片段类型（时变与恒定）和深度，但不取决于片段顺序。这一结果表明，对可懂度的影响取决于竞争音的总体频率变化量，但不取决于其频谱时间相干性。
