Institut für Hörtechnik und Audiologie, Jade Hochschule, D-26121 Oldenburg, Germany.
Signal Processing Group, Department of Medical Physics and Acoustics, and Cluster of Excellence Hearing4All, University of Oldenburg, D-26111 Oldenburg, Germany.
J Acoust Soc Am. 2020 Jan;147(1):85. doi: 10.1121/10.0000509.
Acoustic feedback in hearing aids occurs due to the coupling between the hearing aid loudspeaker and microphones. In order to reduce acoustic feedback, adaptive filters are often used to estimate the feedback path. To increase the convergence speed and decrease the computational complexity of the adaptive algorithms, it has been proposed to split the acoustic feedback path into a time-invariant fixed part and a time-varying variable part. A key question of this approach is how to determine the fixed part. In this paper, two approaches are investigated: (1) a digital filter design approach that makes use of the signals of at least two hearing aid microphones and (2) a defined physical location approach using an electro-acoustic model and the signals of one hearing aid microphone and an additional ear canal microphone. An experimental comparison using measured acoustic feedback paths showed that both approaches enable one to reduce the number of variable part coefficients. It is shown that individualization of the fixed part increases the performance. Furthermore, the two approaches offer solutions for different requirements on the effort to a specific hearing aid design on the one hand and the effort during the hearing aid fitting on the other hand.
助听器中的声反馈是由于助听器扬声器和麦克风之间的耦合引起的。为了减少声反馈，通常使用自适应滤波器来估计反馈路径。为了提高自适应算法的收敛速度和降低计算复杂度，已经提出将声反馈路径分为时不变固定部分和时变可变部分。这种方法的一个关键问题是如何确定固定部分。本文研究了两种方法：（1）利用至少两个助听器麦克风信号的数字滤波器设计方法；（2）使用电声模型和一个助听器麦克风信号以及一个附加耳道麦克风的定义物理位置方法。使用测量的声反馈路径进行的实验比较表明，这两种方法都可以减少可变部分系数的数量。结果表明，固定部分的个性化可以提高性能。此外，这两种方法针对特定助听器设计的努力和助听器适配过程中的努力提出了不同的解决方案。
