It was somewhere outside Barstow when "David"
wrote:

Yes Andy . I had a thought about those last night - Not all night. But
having used the sanders in the past all i can remember is a lot of high
frequency noise.

That's because they're American, and American power tools (the good
"classic" ones) are beautifully made but pitifully badly designed.
Much of the noise is actually siren or whistle noise from the airflow,
which is just sloppy design work. Last floor sander I used was Italian
- very quiet in comparison.