After the article about the generator we bought to use with Cocoon, our travel trailer, several people have asked: “How loud is it?” To give you some feel for the sound the generator makes, I made some rudimentary measurements with a sound pressure level meter.
First things first, I am not a sound engineer. I will address measurement accuracy later.
Caveats
This is a sample of only one generator, and all generators vary. These readings are not necessarily representative of even other generators of the same make and model.
Most certainly, the absolute values of these measurements are not a reliable way to compare generators of various makes and models. Especially when the measurements are from various sources.
Understand how a manufacturer or comparison tester makes their sound level measurements and use your judgment.
Thanks to Fred Seitel and the Sonoma County Radio Amateurs for the article that inspired the measurements.
Measurement Accuracy
These are the things that could contribute to inaccuracy in the measurements:
Ambient Noise
These readings were not measured in a sound-proof room, and there is ambient noise inherent in the measurements.
To normalize, not remove, the ambient noise, I used the meter’s MIN feature to take measurements until the minimum stabilized. This tended to filter out the louder transient noises like birds, high-altitude jets, vehicles, and such. The normalized ambient readings before and after the testing were similar.
The Meter
The meter is certified Level 2 and has an error of +/- 1.5dBA. The manufacturer calibrates it from the factory and recommends recalibration once per year. It is a new meter and likely the least concern for inaccuracy.
Other Accuracy Notes
Because of space limitations, some objects in the near field of the test could reflect some sound into the meter. I am not sure if they are significant or if corn makes good sound tiles.
I noticed halfway through the test when vibration was high the aluminum table made some noise. It was only audible to me near the table.
Measurements
The measurements were made from 23 feet using the dBA scale. The normalized ambient level was 37.9 before and 36.5 dBA after the test.
Note that the generator increases the unloaded ECO idle speed when the propane line is inserted. So in ECO mode on gasoline, the generator with no load idles slower.
The side of the generator with the gas cap is the left side.
Gasoline No Load
| Fuel | Setting | Direction | Level (dBA) | |
| gasoline | STD | front | 62.5 | |
| gasoline | STD | right | 64.1 | |
| gasoline | STD | left | 61.3 | |
| gasoline | STD | rear | 64.9 | |
| gasoline | ECO | front | 54.2 | |
| gasoline | ECO | right | 55.3 | |
| gasoline | ECO | left | 53.5 | |
| gasoline | ECO | rear | 57.7 |
Propane No Load
| Fuel | Setting | Direction | Level (dBA) | |
| propane | STD | front | 60.3 | |
| propane | STD | right | 63.5 | |
| propane | STD | left | 61.3 | |
| propane | STD | rear | 64.4 | |
| propane | ECO | front | 58.1 | |
| propane | ECO | right | 63.8 | |
| propane | ECO | left | 63.4 | |
| propane | ECO | rear | 59.9 |
1,500 Watt Load
| Fuel | Level (dBA) | |
| gasoline | 61.2, 62.9 | |
| propane | 62.6, 62.7 |