The sound absorption guiding cone is made of foam material, which can reduce the secondary noise and guide the flow.

吸声导流锥是利用泡沫塑料作吸声体，降低二次噪声，并有导流作用。

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This type blower has been successfully developed to solve the secondary noise pollution, the difficult problem caused by Roots blowers which are used for the aeration of wastewater.

三叶型罗茨鼓风机具有低噪声的特点，解决了污水处理设备中应用罗茨鼓风机进行曝气带来的二次嗓声污染的难题。

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What looks to be a secondary mic for noise cancellation, at the top, next to the headphone jack

顶部的耳塞插口边上的物体看似用于除噪的第二麦克风

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That leaves us with the top of the device, where there's a 3.5mm headset jack and secondary noise-cancelling microphone, and the bottom which houses the main microphone and micro-USB port.

ENGADGET: Samsung Focus 2 review Mobile