Only the constant sound of the river below the shaft broke the ominous silence.

Always his ears were tuned to that constant hissing sound.

Mixed in with this more constant sound was the familiar rhythm of battle joined.

The sound of birds and animals, once constant, was snuffed out.

Some patients need a dark, quiet, cool room; others may need a constant sound to help them sleep.

You could hear the constant sound from the far reaches of the parking lot.

A constant sound had played at the edges of his consciousness.

There was no sound in the room now but that of the flowing water, unseen and constant.

The bats led Martin away from the ledge with its constant sound of falling water.

But the constant sound of the rain began to grate on her nerves again.