Sign waving Rally at Hilo Air. Tues. 9-19 3-5pm

[Eric1600]

The ambient sound level in my neighborhood is around 25 db. When a helicopter Flys by it jumps to 40 to 45 db and lasts for 30 seconds or so.

That sounds about right. For reference coquis hit 70-80 dB and can go four hours.