She was silent for a moment, only the deep drone of the car's AC to break the quiet.

Instead, he looked at a glittering metal ceiling and heard a deep, steady drone.

It is at once a deep Celtic drone, a drumbeat and the throb of a vigilant conscience.

The common ground was somewhere in the Pacific, between the didjeridoo's deep drone and the bent and quivering notes of the komungo.

I stood still, blotting sweat from my face and listening, in hopes of picking up the bees' telltale deep drone.

A deep drone filled the sky.

The deep drone of aero-engines altered subtly.

A loud, deep drone filled the area, joined by a higher-pitched, tremulous whine.

It was a dull drone, deep and insistent, like the quaking of the distant thunder.

The howl diminished to a deep drone.