In this video we compare the sound of two rock tumblers. A large hobbyist tumbler with a rubber barrel and a tiny toy tumbler with a plastic barrel.
The toy tumbler makes a lot more noise for two reasons: 1) the rocks are tumbling in a plastic barrel, and, 2) the inexpensive motor growls while it runs.
If you want a quiet tumbler buy one with a rubber barrel. Tumblers with a rubber barrel cost a little more, but they also have motors that make less noise and usually operate without problems for years.
We have an article about rock tumbler noise at...
http://rocktumbler.com/tips/how-much-...
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