The products claim that a flat, featureless, continuous sound somehow encourages slumber.

这个产品宣称以平和，连续的声音鼓励睡眠。

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The feature would be even better if the built-in speakers weren’t on the back of the device, muffling the sound if you place it screen up on a flat surface.

如果内置扬声器不是装备在机器的背面，这个功能会更加出色。 因为当你屏幕向上把Kindle放在平坦的表面上时，声音会被压低。

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No giant sucking sound, just the gentle hissing of an inner tube losing air, threatening a flat tire that could send the American dream machine off the road.

即便听不到较大的泄气声，只是嘶嘶地缓慢漏气，也会使名为“美国梦”的这台汽车的轮胎瘪掉，而偏离了正确的道路。

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In two seconds flat there was the sound of a person thundering up the stairs and knocking at the door.

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If you're listening closely, you'll notice that songs streamed over Bluetooth sound a bit flat and soft around the edges.

WSJ: Bluetooth Speakers: The Untethered Sound System

The flat voice acting aside, sound design is also fine, with some nice touches like the occasional burst of birdsong.

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