Stiefenhofer Georg
WS Audiology, Lynge, Denmark.
Int J Audiol. 2023 May;62(5):424-432. doi: 10.1080/14992027.2022.2049380. Epub 2022 Mar 17.
The delay in digital hearing aids is known to cause distortions due to the mixing of the delayed hearing aid sound with the undelayed direct sound. The most apparent delay-based distortion is a pitch sensation referred to as coloration-pitch. This study investigated coloration-pitch discrimination at the lower end of typical hearing aid delays and aimed at establishing thresholds where a large change in coloration-pitch is just perceptible.
Simulations were verified against a reference hearing aid for numerous conditions of delay, insertion gain and incident direction. The simulations were used in a psycho-acoustics experiment in which coloration-pitch discrimination thresholds were measured as a function of hearing aid delay and gain. Participants discriminated between coloration-pitches produced by delay changes of 12%. Insertion gains compensating for mild to moderate hearing losses were used.
Nine normal-hearing and twelve hearing-impaired participants with mild to moderate hearing loss participated.
The simulations accurately reflected the acoustics of the open-fit hearing aid. Discrimination thresholds were between 0.3 ms and 1 ms depending on insertion gain and hearing status.
High sensitivity for changes in coloration-pitch was found for delays >1 ms. For shorter delays participants were increasingly insensitive to changes in coloration-pitch.
众所周知，数字助听器的延迟会导致延迟的助听器声音与未延迟的直达声混合而产生失真。最明显的基于延迟的失真是一种被称为“染色音高”的音高感觉。本研究调查了在典型助听器延迟下限处的染色音高辨别能力，并旨在确定染色音高有明显变化时刚好可察觉的阈值。
针对多种延迟、插入增益和入射方向条件，将模拟结果与参考助听器进行了验证。这些模拟用于一项心理声学实验，在该实验中，测量了作为助听器延迟和增益函数的染色音高辨别阈值。参与者辨别由12%的延迟变化产生的染色音高。使用了补偿轻度至中度听力损失的插入增益。
九名听力正常的参与者和十二名轻度至中度听力损失的听力受损参与者参与了研究。
模拟结果准确反映了开放式助听器的声学特性。辨别阈值在0.3毫秒至1毫秒之间，具体取决于插入增益和听力状况。
发现对于大于1毫秒的延迟，对染色音高变化具有高灵敏度。对于较短的延迟，参与者对染色音高变化越来越不敏感。
