Abstract New-borns are exposed to high noise levels inside infant incubators. Some authors suggest that these noise levels are amplified by the reverberant nature of the materials that compose incubators. In this paper, the impulse response and the reverberation time of an incubator with standard dimensions were calculated. Two incubator configurations were evaluated, with and without mattress, under two measurements methods, impulsive, and interrupted noise method. The incubator was considered as a linear time-invariant system, and therefore the impulse response was easily obtained for each configuration and measurement method. Consequently, the impulse response for each of the six-octave bands was obtained to get the reverberation time in each band. Results show reverberation times (T30) with mattress of 0.6 s (average of all 1/8 octave band frequencies), measured in a room with controlled acoustic conditions (reverberation time of the room below 0.15 s). The longest sound persistence was obtained at low frequencies, with a reverberation time of 1.47 s in the configuration with mattress, and of 1.87 s in the one without mattress. Even if the average reverberation time is relatively reasonable for a standard room, it may be considered long and uncomfortable for such a small space. It is essential to highlight that, due to the low acoustic isolation of the incubator dome, there is a considerable influence of the reverberation time of the room in which the incubator is located.

中文翻译：

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新生儿培养箱的混响时间测量

摘要 新生儿暴露在婴儿保育箱内的高噪音环境中。一些作者认为，构成孵化器的材料的混响性质会放大这些噪音水平。本文计算了标准尺寸培养箱的脉冲响应和混响时间。在两种测量方法（脉冲法和间断噪声法）下评估了两种培养箱配置，带床垫和不带床垫。孵化器被认为是一个线性时不变系统，因此很容易获得每种配置和测量方法的脉冲响应。因此，获得了每个 6 倍频程频段的脉冲响应，以获得每个频段的混响时间。结果显示混响时间 (T30)，床垫为 0。6 秒（所有 1/8 倍频带频率的平均值），在具有受控声学条件的房间（房间的混响时间低于 0.15 秒）中测量。在低频下获得最长的声音持久性，在有床垫的配置中混响时间为 1.47 秒，在没有床垫的配置中为 1.87 秒。即使标准间的平均混响时间相对合理，但对于这么小的空间来说，可能会被认为是漫长的和不舒服的。必须强调的是，由于孵化器圆顶的低隔音性，孵化器所在房间的混响时间有相当大的影响。带床垫配置的混响时间为 1.47 秒，不带床垫配置的混响时间为 1.87 秒。即使标准间的平均混响时间相对合理，但对于这么小的空间来说，可能会被认为是漫长的和不舒服的。必须强调的是，由于孵化器圆顶的低隔音性，孵化器所在房间的混响时间有相当大的影响。带床垫配置的混响时间为 1.47 秒，不带床垫配置的混响时间为 1.87 秒。即使标准间的平均混响时间相对合理，但对于这么小的空间来说，可能会被认为是漫长的和不舒服的。必须强调的是，由于孵化器圆顶的低隔音性，孵化器所在房间的混响时间有相当大的影响。