Honda EU2000i Gas vs Propane noise levels
I just finished one out of two propane conversions for this generator and happened to have an SPL meter I use for studio work. This shows the noise level for gas vs propane for the EU2000i is almost the same. Propane may be just slightly louder on the A weighted scale. C weighted db is the same.
Both generators under 1500W load and SPL meter in exactly the same position each test. I use the SPL meter in A and C weighting modes. A weighting is used for human perception and C is used for mechanical loudness.
A is most useful for this purpose since we're measuring perceived loudness. Propane seems to have a slightly higher perceived loudness.
I didn't notice much difference. I think the perceived loudness may be slightly higher because the generator had a slightly higher pitch running propane.