To avoid attracting unwelcome attention he kept his voice down.

为避免引起不必要的注意，他把声音压低了。

《牛津词典》

"Keep your voice down," I whispered.

“小声点，”我悄声说。

《柯林斯英汉双解大词典》

Keep your voice down—I don't want anyone else to hear.

小声点—别让人听见。

《牛津词典》

This is done in the doctor's office to look down the throat at the voice box and vocal chords.

VOA: special.2009.09.02

And so ease of implementation is actually a very compelling -- metric against which to measure-- -- do you mind toning my voice down a bit-- is a very reasonable measure against which to measure the quality of an algorithm, right.

如此简单的实现实际上是一个很牵强的,度量，与之相对的衡量是-,如果你们不介意，我降低点音量-,是一种用来度量算法质量的,合理的方法。

哈佛公开课 - 计算机科学课程节选

The tempo here is very slow and he slows it down even more and then it just sits out there, this huge wonderful voice that he had, on the leading tone.

速度非常缓慢,经他处理后就更慢了,余音缭绕,他在导音上展现了洪亮,精妙的歌喉

耶鲁公开课 - 聆听音乐课程节选

The phone rang at home the other day, and when I picked it up a voice down a crackly line asked if a "Mr Sellan" was there.

BBC: A phone call for Mr Sellan

Then gradually he let his voice die down.

NEWYORKER: Amundsen

Was it just new job jitters or was some deep down voice really telling me to change course?

FORBES: Poise, Pep and My Power Suit