Each recording had a series of rhyming words that the volunteers had to identify for different levels of background noise.
每段录音都有一系列押韵的单词，志愿者们必须在不同程度的背景噪声下识别这些单词。
2
Each recording had a series of rhyming words that the volunteers had to identify, with and without the intelligent microphone, for different levels of background noise.
每段录音都有一系列的押韵字词，志愿者要在不同程度的背景噪音下佩戴与不佩戴该智能扩音器来辨别这些词。
3
They only make the noise, described as a brief, clear metallic sound made up of a series of notes, when in distress.