We have recently performed sound level tests of all our systems with a dB metre. We want people to have comparison against a well known standard, so we tested against a Honda 2kVA generator running unloaded in eco-mode and also running flat out with maximum load.
The testing was carried out at a six metre distance in an open lot. We had a slight amount of background noise with some distant traffic and a steady breeze, but not too much.
There are three points in the design of our systems related to sound levels.
1. One of the reasons we chose to work with General Pump WM series triplex plunger pump is that is was the quietest pump of its type that we tested.
2. We use a simple needle valve to control pressure instead of a regulator
. One benefit of this is that the valve is quieter than the regulators we tested.
3. For our petrol/gasoline version, we use Honda's extra quiet muffler
. This is the same muffler
as on their portable generators.
As Andrew pointed out above, our systems are definitely not silent. However, we do get regular comments from customers that their AC electric
Rainman is more quiet than expected.