Department of Communication Sciences and Disorders, The University of Iowa, Iowa City, Iowa 52242, USA.
J Acoust Soc Am. 2009 Dec;126(6):3214-26. doi: 10.1121/1.3238161.
The directional microphone systems of modern digital hearing aids are capable of changing their spatial directivity pattern and/or the microphone mode in response to changes in the properties of environmental sounds. These adaptive/automatic features make measurement of a hearing aid's directivity in a given test environment very difficult. Assessing the directivity of such systems requires a signal that can record the system's response while not changing the system's directivity. This paper proposes a method using a signal cancellation technique involving impulse responses to acoustically assess a hearing aid's directivity (referred to as the IR method). The impulse is presumed to be undetectable to the adaptive/automatic system because it contains little energy and a short response could be recorded before the system actually reacts. In the current study, the IR method was evaluated by testing five adaptive/automatic directional hearing aids in noise of various intensities. The results revealed that the IR method was an accurate and repeatable way to assess slow-acting directional systems in noise of varying intensities and fast-acting systems in noise of high intensities.
现代数字助听器的指向性麦克风系统能够根据环境声音特性的变化改变其空间指向性模式和/或麦克风模式。这些自适应/自动特性使得在给定测试环境中测量助听器的指向性变得非常困难。评估此类系统的指向性需要一种信号，该信号可以记录系统的响应而不改变系统的指向性。本文提出了一种使用涉及脉冲响应的信号消除技术的方法，以对助听器的指向性进行声学评估（称为 IR 方法）。假设该脉冲对自适应/自动系统不可检测，因为它能量很少，并且在系统实际反应之前可以记录短的响应。在当前的研究中，通过在各种强度的噪声中测试五个自适应/自动指向性助听器来评估 IR 方法。结果表明，IR 方法是一种准确且可重复的方法，可以评估在不同强度噪声中作用缓慢的定向系统和在高强度噪声中作用快速的系统。
