I've got the F225 upgrade with the foam air filter, noise at ~7500 rpm was 105db measured with an iphone noise meter app and standing about 1.5m from the filter (+20metres above sea level, 85% humidity, 11 C). Attenuation is around 6db for each doubling of the distance so the noise level should be under 100db 3m away and around 95db 6m away. Lots of factors to consider and hardly laboratory conditions but hope this helps.