I didn't really understand what he was talking about, but the noise was becoming increasingly clear.

Suddenly, the noise became an acute whistle that lasted 5 minutes.

A whirlwind of light, and the closer he got, the weaker the black noise became.

The noise sank to a lower register and became stronger.

The noise of the bomber stream was becoming very loud.

The noise becomes even louder and the resident complains again.

The noise became louder, and George could tell the movement was faster now.

The noise was becoming familiar; every few minutes, something collapsed.

And now the noise outside became loud enough to attract the prisoner's attention.

The noises now became muffled and more distant, then suddenly ended.