Formby C, Heinz M G, Luna C E, Shaheen M K
Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21203.
J Acoust Soc Am. 1994 Jul;96(1):102-14. doi: 10.1121/1.410470.
Masked detection thresholds were measured at a center frequency of 2500 Hz for a range of noise signal bandwidths (W = 62 to 6000 Hz) and durations (T = 10 to 480 ms) approximating that found acoustically in speech. The signals were presented in an uncorrelated 480-ms, 6000-Hz-wide masker. The masker was presented: (1) at a constant spectrum level (53 dB SPL/Hz) or (2) with the overall level varied randomly over a 50-dB range from interval to interval of a trial. Performance was disrupted in the random-level masker only for the condition where the signal and uncorrelated masker were gated on and off simultaneously and were matched spectrally. Time constants (tau) estimated from temporal integration functions fit to the masked detection threshold data were related inversely to W for W broader than the critical bandwidth. Sensitivity to the noise signals was evaluated in the context of an optimum-detection model (Green, 1960). The results did not follow the prediction of a constant bandwidth-duration (WT) product, but may be understood in terms of cues available to the listener from the relative combination of signal and masker parameters. At least three cues for detection were identified in these experiments: (1) a relative timing cue, (2) a spectral shape cue, and (3) a traditional energy cue compared across observation intervals. The relative timing cue and spectral shape cue together contributed as much as a 10- to 12-dB advantage relative to detection based on the traditional energy cue alone. A new multi-cue detection model for predicting the masked detection thresholds was derived. Predictions from the new model were highly correlated (r = 0.95) with the empirically measured masked detection thresholds.
在中心频率2500赫兹下，针对一系列噪声信号带宽（W = 62至6000赫兹）和持续时间（T = 10至480毫秒）测量了掩蔽检测阈值，这些带宽和持续时间近似于语音中声学上发现的情况。信号呈现于一个不相关的480毫秒、6000赫兹宽的掩蔽噪声中。掩蔽噪声呈现方式如下：(1) 处于恒定频谱水平（53分贝声压级/赫兹），或 (2) 在一次试验的不同间隔中，总体水平在50分贝范围内随机变化。仅在信号和不相关掩蔽噪声同时开启和关闭且频谱匹配的条件下，随机水平掩蔽噪声会干扰性能。根据拟合到掩蔽检测阈值数据的时间积分函数估计的时间常数（τ），对于比临界带宽更宽的W，与W成反比。在最佳检测模型（格林，1960年）的背景下评估了对噪声信号的敏感性。结果未遵循恒定带宽 - 持续时间（WT）乘积的预测，但可以根据听众从信号和掩蔽噪声参数的相对组合中获得的线索来理解。在这些实验中至少确定了三种检测线索：(1) 相对时间线索，(2) 频谱形状线索，以及 (3) 跨观察间隔比较的传统能量线索。相对于仅基于传统能量线索的检测，相对时间线索和频谱形状线索共同贡献了高达10至12分贝的优势。推导了一种用于预测掩蔽检测阈值的新的多线索检测模型。新模型的预测与经验测量的掩蔽检测阈值高度相关（r = 0.95）。
