A low thrumming could be felt through the deck under their feet.

The only sound was the beating of their wings, a low thrumming that sounded like distant rain.

As they descended, the low thrumming of the ventilation fan grew louder.

Silence hurried to join them, her feet on the rattling stairway drawing a new low thrumming from the keel as she passed.

I darted around the corner into indeterminate light and a deep, low thrumming.

Only then did he hear the low heavy thrumming in the sky.

In the far, far distance, almost at the edge of their hearing, they could just make out the low thrumming of machinery.

Ahead, the sound of machinery rose out of the silence, a low and steady thrumming.

And then the noise Barney had heard; the low thrumming of an engine from the direction of the harbour.

He put his ear against it to listen, and there seemed to be a suggestion of a low, faint thrumming.