Far above, a hollow boom rolled down from something exploding high in the atmosphere.

The light vanished, and a hollow boom rolled across the dark floor.

Then there was a hollow "boom," perhaps the ramp sliding back into place.

The doors closed with a hollow boom; suddenly the air seemed stale.

The church door shut behind him with a hollower boom than it had given anyone else.

Before the hollow boom of it had even died away, the door opened.

A loud, hollow boom as the mallet struck the wall.

The one gave a dull thud, the other a hollow boom.

The hollow boom of the impact echoed throughout the first floor.

The oak door slammed shut behind him with a hollow boom.