Woods William S, Van Tasell Dianne J, Rickert Martin E, Trine Timothy D
Starkey Laboratories, Inc., Eden Prairie, USA.
Int J Audiol. 2006 Nov;45(11):630-44. doi: 10.1080/14992020600937188.
This work was undertaken to answer the question, 'How does the speech audibility/fit-to-gain-target provided by compression change with number of channels?' For each of 957 audiograms and a given number of compression channels, the channel crossover frequencies were set either to maximize the SII (speech intelligibility index) for low- and high-level speech spectra, or to optimize the fit-to-gain targets from the Cambridge method for loudness equalization (CAMEQ). The audiograms comprised all common configurations, and losses ranged from mild to severe. Use of these computational procedures allowed the predicted, channel-number-based performance to be determined separately from the effects of other compression parameters. From one to five channels were sufficient to yield predicted speech recognition performance within 5% of maximum for 90% of the 'mild' and 'moderate' audiograms. Three to nine channels were necessary for the same level of predicted performance for 90% of the 'severe' audiograms. Four channels or fewer were sufficient to produce less than 5 dB rms error in fit to CAMEQ targets for 90% of all audiograms.
开展这项工作是为了回答“压缩提供的言语可听度/增益目标拟合度如何随声道数量变化？”这一问题。对于957份听力图中的每一份以及给定数量的压缩声道，声道交叉频率的设置要么是为了使低水平和高水平言语频谱的言语可懂度指数（SII）最大化，要么是为了根据剑桥响度均衡法（CAMEQ）优化增益目标拟合度。这些听力图涵盖了所有常见配置，听力损失范围从轻度到重度。使用这些计算程序可以将基于声道数量的预测性能与其他压缩参数的影响分开确定。对于90%的“轻度”和“中度”听力图，1至5个声道足以产生在最大值5%以内的预测言语识别性能。对于90%的“重度”听力图，3至9个声道对于达到相同水平的预测性能是必要的。对于90%的所有听力图，4个或更少的声道足以在拟合CAMEQ目标时产生小于5 dB rms的误差。
