Significados de constant thrum en inglés

The constant thrum of the ship's propellers quieted to a purr.

Behind him, he could feel a constant thrum of energy radiating from the Eldunarí.

In the background there's a constant thrum of engine.

Or maybe it was the constant thrum of magic in the air that caused the sensation.

And requests that they be on the far side of the building, near the constant thrum of the interstate.

So why do we hear a constant thrum of bad news from people involved in making, distributing and retailing music sold as traditional formats?