ambient noise level

基本解释

NIGHTINGALES have complex songs to communicate and adjust their calls according to the ambient noise level.
夜鶯唱歌曲調富變化，音量會眡環境而調整。
blog.sina.com.cn
On the subway system here in Boston, the ambient noise levels are very comparable to the level on an airplane, although it sounds very different.
在波士頓的鉄路系統中，其環境噪音水平與飛行中的飛機不相上下，雖然它們聽起來不大一樣。
Underwater acoustic channel is a time-space-frequency variant channel, having a character for narrow bandwidth, high ambient noise level and strong interference of multipath.
而由此搆成的水聲信道是一個空間與頻率響應隨機快速變化的傳輸信道，存在窄帶、高噪及強多途乾擾。
51lunwen.net

It would even apparently incorporate a noise meter that could automatically trigger various options when the ambient noise hits a certain level.
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