城市治理新妙招

Speaker System Blocks City Noise

广播系统阻断了城市噪声

Restaurants, schools, dentist offices are all keeping more windows open to increase ventilation—and, hopefully, to decrease the chances of encountering the coronavirus. But letting in fresh air also lets in more noise.

饭店、学校、牙医诊所都打开窗户保持空气流通——希望降低感染新冠肺炎的机会。但是通风意味着更多噪声。

Now researchers have come up with a device that’s like noise-cancelling headphones—but for a building.

现在研究者们提出使用一种设备例如像消声耳机来降低噪声，但这是给建筑用的。

“It works on the same principle, so it detects noise that’s coming into the windows and then is cancelling the noise.”

“它使用同样的原理，当发现噪声从窗户进来时，消除它。”

Bhan Lam, an acoustical engineer at Nanyang Technological University in Singapore.

Bhan Lam是一位新加坡南洋理工大学的声学工程师。

The device looks like a grid of small speakers and fits over an open window. A microphone samples incoming noise, then sends the speaker grid instructions on what sort of “antinoise” to emit. The result is to cancel out the incoming sound.

这个装置像是有很多小的扬声器组成的阵列，并且与窗口一样大。手机分析传入的噪声，然后扬声器阵列装置向外传播一种叫反噪声的声音，结果是相互抵消。

For example, here’s the sound of a commuter train in Singapore with no noise control.

例如，这是没有噪声消减的新加坡上下班的声音。

Now here’s that same train sound with the array of noise-cancelling speakers turned on.

现在把消音扬声器打开。

Compare that to a closed window.

把它与关窗的情况下进行比较。

The antinoise device is almost as good and allows air to keep flowing into and out of the window. The details are in the journal Scientific Reports.

这一消声设备效果很好，且允许新鲜空气从窗户进入。细节发布在科学报告杂志上。

The device is just a prototype—so it’s still expensive. And it doesn’t block out all sounds. It masks sound at frequencies from 300 to 1000 Hz—which includes the rumble of freeways, trains and planes. But even that could come in handy in a place like Singapore.

这个装置只是个原型——所以它还是很贵的，并且它不可以阻断所有的噪声。它可以过滤频率在300到1000赫兹——包括高速公路的隆隆响声、火车和飞机的噪声，可以在新加坡派上用场。

“Gimme a second, there’s a plane flying past.”

“等一下，有架飞机飞过。”

Bhan says Singapore already has a lot of green buildings that use natural ventilation.

Bhan说道新加坡已经有很多绿色建筑使用了自然通风装置。

“But the downside is: when you have lots of openings in the buildings, the noise comes in, so you need some way to manage the increasing noise.”

“但是缺点的是，当有许多通风的建筑时，会有更多噪声传入，你需要处理这些增加的噪声。”

A grid of window speakers could do the trick—especially if people prioritize peace and quiet over a good view, which folks at home tend to do all night.

这一消声装置可以做到——尤其是人们更喜欢安静和平的环境，住在家里的人都喜欢这么做。