In the echoing corridors the booming of the heavy sea formed a constant background.

It's a constant background, and it gets a little louder each time you draw on it.

Despite a constant background of coughing - flu season in old Vienna?

For many if not most members of the class of 2007, the war in Iraq has been the constant background of their college years.

The sound of camera shutters formed a constant background as nearly every action was recorded in photographs and on audio tape.

The adults talked among themselves, worked, or read while the children's voices created a constant background of musical chatter.

That sound, a constant background hum down on the flatlands, never reached his home in the mountains.

The general feeling is of a constant background, while more direct "messages' come only occasionally.

Once through there the radiation drops to lower levels, with a constant background of high energy cosmic rays which pose a health threat.