bullhorn

大声公、手提扩音器、扩音喇叭美式

The officer shouted instructions to the crowd through a bullhorn.

那名警员用大声公向人群喊出指示。

用扩音器喊话、大声宣布少用

The organizers bullhorned the new meeting time to everyone outside.

主办单位用扩音器向外面的所有人喊出新的集会时间。