So you hear those hard, flat sounds.

所以你会听到那些坚硬、平坦的声音。

He convinced his father to buy him a chromatic harmonica – one that makes sharp and flat sounds.

他说服他的父亲给他买了一把半音阶口琴——一种发出尖锐和平坦声音的口琴。

There was a dull flat sound at the back of the place, behind the closed door beyond the crap table.

在这个地方的后面， 在赌桌后面紧闭的门后， 传来沉闷而平淡的声音。