sound frequency range

Any Bell Labs engineer would be familiar with the idea of reducing the frequency range of speech, since the telephone cut off sound above 4000 Hz.

贝尔实验室的任何一个工程师，对降低声音的频率范围都很熟悉，因为电话会削去4000Hz以上的声音。

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Frequency spectrum analysis of sound radiation from a range hood fan is combined with auditory feature for abnormal sound fault diagnosis of a range hood.

对油烟机风机辐射噪声进行频域特征分析、结合人工听觉判断油烟机异音故障。

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