3 weeks of the rock tumbler(s) echoing down the hall. At times I don't notice it, other times it grates upon you. It's remarkable the range of sounds, sometimes like a bathtub forever draining, like an overfilled washer, listening to it when you're trying to fall asleep you can hear music in the squeaking of the gears, distant, remote, distant muttering voices, melodies, gregorian chants played as if through an ancient gramaphone.
I'm down to one polisher, the other stopped working, the problem somewhere in the motor, intermittent, a victim of my impatience to process the hundreds of pounds of pebbles and fossils we've collected over the year. I've taken it apart as I'm somewhat handy and maybe I'll find time to repair it...