Before, there had been a very faint but steady humming of power, undoubtedly from whatever unseen engines powered the bizarre vessel.

Behind them, the distant shouts of the Hordes faded and were replaced by the steady humming of the city's machines.

Rising above wailed chants and steady humming, a male voice inside called out: "Great spirit, we pray for the sacredness of our ancestors' graves.

She could hear the steady humming of computers in the offices she passed, but didn't pause until she reached a corner office.

For a long time, the only noise that accompanied the sound of his feet was the steady humming of the Great Machine.

The witnesses would hear the genny as a steady low humming, and the lights all over the prison would brighten.

There were still the sounds of the storm outside, but the light had faded to a blue-white glow, and the sound into a steady humming.

The steady humming of the air conditioning could be the distant roar of rocket engines.

The steady humming of the powerful engines, the noise of servicing being performed on thousands of standard automatic computer systems--always something.

A while ago, he had fancied that he heard the steady humming of a motor, but that had ended before he reached Howard's estate.