Sea Mammal Research Company, Julianalaan 46, 3843 CC Harderwijk, The Netherlands.
J Acoust Soc Am. 2012 Aug;132(2):607-10. doi: 10.1121/1.4733552.
The distance at which harbor porpoises can hear underwater detonation sounds is unknown, but depends, among other factors, on the hearing threshold of the species for impulsive sounds. Therefore, the underwater hearing threshold of a young harbor porpoise for an impulsive sound, designed to mimic a detonation pulse, was quantified by using a psychophysical technique. The synthetic exponential pulse with a 5 ms time constant was produced and transmitted by an underwater projector in a pool. The resulting underwater sound, though modified by the response of the projection system and by the pool, exhibited the characteristic features of detonation sounds: A zero to peak sound pressure level of at least 30 dB (re 1 s(-1)) higher than the sound exposure level, and a short duration (34 ms). The animal's 50% detection threshold for this impulsive sound occurred at a received unweighted broadband sound exposure level of 60 dB re 1 μPa(2)s. It is shown that the porpoise's audiogram for short-duration tonal signals [Kastelein et al., J. Acoust. Soc. Am. 128, 3211-3222 (2010)] can be used to estimate its hearing threshold for impulsive sounds.
宽吻海豚能够听到水下爆炸声音的距离尚不清楚，但取决于物种对脉冲声音的听觉阈值等因素。因此，使用心理物理学技术来量化设计模仿爆炸脉冲的脉冲声音的年轻宽吻海豚的水下听觉阈值。使用具有 5 ms 时间常数的合成指数脉冲，由水池中的水下投影仪产生并传输。产生的水下声音虽然受到投影系统和水池的响应的影响，但具有爆炸声音的特征：零到峰值声压级至少比声暴露级高 30 dB（参考 1 s(-1))，并且持续时间短（34 ms）。动物对这种脉冲声音的 50%检测阈值出现在接收到的未加权宽带声暴露级为 60 dB re 1 μPa(2)s 时。结果表明，短持续时间音调信号的海豚听力图[Kastelein 等人，J. Acoust. Soc. Am. 128, 3211-3222（2010）]可用于估计其对脉冲声音的听力阈值。
