The agent in this case can play a low sound while voltage is within correct parameters and a high-pitched sound when a problem occurs.

在这种情况下，代理可以在电压正常时发出低沉的声音，而在出现问题是发出高亢的声音。

youdao

Some animals' voices are high-pitched, others are low.

一些动物的叫声很尖锐，别的很低沉。

youdao

There's the low growl, the more intense medium growl, and the high-pitched screech.

这些人声包括低吼，更有力的中音咆哮，还有尖利的高音。

youdao

The technology would enable a person talking to someone with a loud, high-pitched, rapid-fire voice to sound similar even if his actual voice was soft, low and slow, for instance.

FORBES: Stanford Developing Vocal Cosmetics Technology To Make Cellphone Talkers More Likable