the range of distance within which it is possible to be heard or to hear what someone is saying听力可及的范围;可听距离
I don't think you should say anything while the boss is still in/within earshot.我觉得,老板还没走远你应该什么也别说。
Wait till she's out of earshot before you say anything.等她走远听不见了,你再说不迟。