This study concludes a larger project on the frequency-dependent susceptibility to noise-induced temporary hearing threshold shift (TTS) in harbor seals (Phoca vitulina). Here, two seals were exposed to one-sixth-octave noise bands (NBs) centered at 0.5, 1, and 2 kHz at several sound exposure levels (SELs, in dB re 1 μPa²s). TTSs were quantified at the center frequency of each NB, half an octave above, and one octave above, at the earliest within 1–4 min after exposure. Generally, elicited TTSs were low, and the highest TTS_1–4 occurred at half an octave above the center frequency of the fatiguing sound: after exposure to the 0.5-kHz NB at 210 dB SEL, the TTS_1–4 at 0.71 kHz was 2.3 dB; after exposure to the 1-kHz NB at 207 dB SEL, the TTS_1–4 at 1.4 kHz was 6.1 dB; and after exposure to the 2-kHz NB at 215 dB SEL, TTS_1–4 at 2.8 kHz was 7.9 dB. Hearing always recovered within 60 min, and susceptibility to TTS was similar in both seals. The results show that, for the studied frequency range, the lower the center frequency of the fatiguing sound, the higher the SEL required to cause the same TTS.

中文翻译：

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由于以0.5、1和2 kHz为中心的六分之一音阶噪声带，海豹（Phoca vitulina）的临时听力阈值偏移

这项研究得出了一个更大的项目，即对海豹（Phoca vitulina）中噪声引起的临时性听力阈值漂移（TTS）的频率依赖性敏感性。在这里，两个密封件暴露于在0.5％，1为中心的六分之一倍频程频带噪声（NBS），和2千赫在几个声暴露水平（的SEL，以dB为单位重新1μPa ^2个S）。最早在暴露后1-4分钟内，在每个NB的中心频率（分别高出半个八度和高出一个八度）对TTS进行定量。通常，诱发的TTS较低，最高TTS _1-4发生在疲劳声音中心频率以上的八度处：在210 dB SEL下暴露于0.5 kHz NB后，TTS _1-4在0.71 kHz时为2.3 dB; 暴露于207 dB SEL的1-kHz NB后，1.4 kHz的TTS _1-4为6.1 dB；在215 dB SEL下暴露于2 kHz NB之后，在2.8 kHz下的TTS _1-4为7.9 dB。听力总是在60分钟内恢复，并且两种海豹对TTS的敏感性相似。结果表明，对于研究的频率范围，疲劳声音的中心频率越低，引起相同TTS所需的SEL越高。