Hartmann William M, Constan Zachary A
Department of Physics and Astronomy, Michigan State University, East Lansing 48824, USA.
J Acoust Soc Am. 2002 Sep;112(3 Pt 1):1037-45. doi: 10.1121/1.1500759.
The interaural level difference (ILD) plays a significant role in sound localization. However, the definition of ILD for noise is open to some interpretation because it is not obvious how to deal with the inevitable level fluctuations. In this article, the ILD is interpreted as an energylike (time-integrated) measure of stimulus level, independent of other stimulus details-particularly interaural correlation. This concept is called the "level-meter model." The model was tested by measuring human ILD thresholds for noise stimuli that were interaurally correlated, or anticorrelated, or uncorrelated. An additional test (not involving lateralization) measured the threshold for level discrimination based on loudness. According to the level-meter model, all four thresholds should be the same. The experimental results showed that the predictions of the level-meter model held good to within about half a dB, although thresholds for level discrimination were systematically higher than ILDs. Among the ILDs themselves, thresholds were slightly higher for uncorrelated noise. The latter result could be explained by replacing the level-meter model with a loudness-meter model, incorporating temporal integration. The same model accounted for the bandwidth dependence of the threshold.
双耳声级差（ILD）在声音定位中起着重要作用。然而，噪声的ILD定义存在一些可解释之处，因为如何处理不可避免的声级波动并不明显。在本文中，ILD被解释为一种类似于能量（时间积分）的刺激声级度量，独立于其他刺激细节，特别是双耳相关性。这个概念被称为“声级计模型”。该模型通过测量双耳相关、反相关或不相关的噪声刺激的人类ILD阈值进行了测试。另一个测试（不涉及定位）测量了基于响度的声级辨别阈值。根据声级计模型，所有四个阈值应该是相同的。实验结果表明，声级计模型的预测在大约半分贝范围内是有效的，尽管声级辨别阈值系统地高于ILD。在ILD本身中，不相关噪声的阈值略高。后一个结果可以通过用包含时间积分的响度计模型取代声级计模型来解释。相同的模型解释了阈值的带宽依赖性。
