I second.
I have a Thumler’s dual barrel model. I run it in my basement and can’t hear anything from the floor above.
I’m a silver smith/jewelry maker so I rarely use the tumbler for polishing stones. I use it to tumble finished pieces in steel shot to harden parts that have become annealed during soldering. Tumbling time in this application is only 3-4 hours instead of weeks as is normal for rock polishing.
