Listening to the trains one morning at the age of five, he noticed that when the sound reached a certain pitch, it made the window vibrate.

5岁的一天早晨，他听到了火车的声音，注意到当声音到达一定高度时，窗户开始震动。

youdao

It is caused by the Doppler effect (something similar happens when a police car or fire engine with its siren blaring drives past you, and the pitch of the sound suddenly drops).

这是由多普勒效应(类似一辆警车或消防车鸣着警笛从你身边经过，之后音高突然下降)引起的。

youdao

Even a simple note on my guitar has an array of harmonic frequencies. But the frequencies have a special harmonic relationship, which is why you hear it as a single sound with a single pitch.

即使是一把吉他上一个简单的音节都有一系列的谐振频率，而这一系列的谐振频率都有着特殊的谐振关系，这也正是为什么我们听到的只是某一音调上的一个单音。

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The team now runs on to the pitch preceded by the sound of Cossack music, in grateful tribute to their benefactor.

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It isn't the pitch you need to listen for, but the length of the sound itself.

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Murrin's rapid-fire pitch begins to sound, after a time, like the finger-wagging of a know-it-all parent.

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