Stone Michael A, Canavan Shanelle
Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, M13 9WL, United Kingdom.
Manchester Centre for Audiology and Deafness, School of Health Sciences, University of Manchester, Manchester, M13 9PL, United Kingdom.
J Acoust Soc Am. 2016 Aug;140(2):832. doi: 10.1121/1.4960483.
Stone and Moore [(2014). J. Acoust. Soc Am. 135, 1967-77], showed that the introduction of explicit temporal-only modulations to a speech masker, that otherwise produced a near-constant envelope at the output of each auditory filter, rarely resulted in improved intelligibility, except at a very low modulation rate. This represents a failure in "dip-listening" or "glimpsing" [Cooke (2006). J. Acoust. Soc. Am. 119, 1562-1573], a facility where listeners are presumed to benefit from the temporarily improved signal-to-noise ratio during the masker dips. The dips of Stone and Moore only varied temporally, so Stone and Moore's method was used here to investigate the effect of maskers with both spectral and temporal dips, a pattern more representative of real-world maskers. For sinusoidally shaped modulations, intelligibility improved only at very low modulation rates, below 2 Hz temporally and 0.14 ripples/auditory filter spectrally. Square-wave modulation at a rate of 4 Hz resulted in improved intelligibility when only one cycle of spectral modulation was present across the audio bandwidth. Compared to the spectro-temporal extent of dips present during real-world noisy speech, dips generated by the reported modulation patterns were very large, further supporting the notion that dip-listening reflects a release from modulation masking and not energetic masking.
斯通和穆尔[（2014年）。《美国声学学会杂志》135卷，1967 - 1977页]表明，在语音掩蔽器中引入仅明确的时间调制，在每个听觉滤波器的输出处原本会产生近乎恒定的包络，但除了在非常低的调制率下，很少能提高可懂度。这代表了“低谷聆听”或“瞥见”[库克（2006年）。《美国声学学会杂志》119卷，1562 - 1573页]的失败，在这种情况下，假定听众会从掩蔽器低谷期间暂时改善的信噪比中受益。斯通和穆尔的低谷仅在时间上变化，所以这里采用斯通和穆尔的方法来研究具有频谱和时间低谷的掩蔽器的效果，这种模式更能代表现实世界中的掩蔽器。对于正弦形调制，可懂度仅在非常低的调制率下有所提高，时间上低于2赫兹，频谱上低于0.14波纹/听觉滤波器。当在音频带宽内仅存在一个频谱调制周期时，4赫兹速率的方波调制会提高可懂度。与现实世界中嘈杂语音期间出现的低谷的频谱 - 时间范围相比，所报道的调制模式产生的低谷非常大，这进一步支持了低谷聆听反映的是从调制掩蔽而非能量掩蔽中解脱出来的观点。
