When designing closed-loop electro-acoustic systems, which can commonly be found in hearing aids or public address systems, the most challenging task is canceling and/or suppressing the feedback caused by the acoustic coupling of the transducers of such systems. In many applications, feedback cancelation based on adaptive filters is used for this purpose. However, due to computational complexity such a feedback canceler is often limited in the length of the filter’s impulse response. Consequently, a residual feedback, which is still audible and may lead to system instability, remains in most cases. In this work, we present enhancements for model-based postfilters based on a priori knowledge of the feedback path which can be used cooperatively with the adaptive filter-based feedback cancelation system to suppress residual feedback and improve the overall feedback reduction capability. For this, we adapted an existing reverberation model such that our model additionally considers the presence and the performance of the adaptive filter. We tested the effectiveness of our approach by means of both objective and subjective evaluations.

中文翻译：

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使用基于扩展模型的后置滤波器抑制残余反馈

在设计助听器或公共广播系统中常见的闭环电声系统时，最具挑战性的任务是消除和/或抑制由此类系统的换能器的声学耦合引起的反馈。在许多应用中，基于自适应滤波器的反馈消除用于此目的。然而，由于计算复杂性，这种反馈消除器通常受限于滤波器脉冲响应的长度。因此，在大多数情况下仍然存在残留反馈，该反馈仍然是可听见的并且可能导致系统不稳定。在这项工作中，我们基于反馈路径的先验知识提出了基于模型的后置滤波器的增强功能，可以与基于自适应滤波器的反馈消除系统配合使用，以抑制残余反馈并提高整体反馈减少能力。为此，我们调整了现有的混响模型，以便我们的模型额外考虑自适应滤波器的存在和性能。我们通过客观和主观评估测试了我们方法的有效性。