The seat rows only backscatter frequencies above a certain threshold, though, so they act, in effect, as a sound filter.

每排座椅只反射高于一定频率的声音，因此实际上它们充当的是声音过滤器。

youdao

Researchers took 12 fish tanks, and killed the gurgling filter sound to mimic the quiet of a calm lake.

研究人员找来12个大鱼缸，想办法消掉过滤器的潺潺声，以模拟安静的湖水环境。

youdao

This may sound confusing, but in practice you don't really need to worry about the details; the important thing is that this ACTS to filter out unnecessary information.

这听起来可能让人感到迷惑，但实际上，您不用为这些细节担心；重要的是这项操作可以过滤掉不必要的信息。

youdao

In humans the vocal tract acts as a filter on the sound from the source, and the "source-filter theory" held that the separate, fine control of the vocal tract to be the product of a long evolution in the development of the subtleties of speech.

BBC: Helium-huffing gibbons 'sing with soprano technique'

The sound is reproduced either by the sound system of the S-Class or by Sennheiser Noise Gard headphones, which filter out any unwanted ambient noise for unparalleled listening pleasure.

ENGADGET: Brabus iBusiness luxury sedan puts an iPad at every seat, a Magic Mouse at every hide-covered armrest