People might have subwoofers as part of their stereo system.

人立体音响系统中可能有重低音喇叭。

Now, you can't hear when the speakers are switched on.

打开低音喇叭时人并不会听到什么声音。

These are specialized speakers. Kind of like sub-subwoofers. People might have subwoofers as part of their stereo system.

这些是非常专业扬声器，有点像低音炮。低音喇叭常常作为立体声系统一部分。

In a little while could be heard the music of the bass horns, the clear voices of the children and the men's deeper notes.

过了一会儿， 可以听到低音喇叭音乐、孩子清晰声音和男人低沉音符。