"I do not know either," Maulkin rumbled softly when the silence had grown long.

They all advanced together, rumbling softly, mutely, like the sea.

A huge, gray machine rumbled softly, yet with undeniable strength and power.

"Try and forget how the man looks," Hawke rumbled softly.

The being scrutinized the American for a moment, then made a deep bow, rumbling softly.

The ground rumbled softly as the shuttle lifted into view above the terminal.

Thunder rumbled softly in the distance, but above him the clouds were breaking up.

A ship was out there, heard but not seen, its diesel engines rumbling softly as it went by.

"Give me some trouble," he softly rumbled from his barrel chest.

"I know what has happened," the deep voice rumbled softly.