We had Brood X here. They were loud enough that we could clearly hear them even when we drove on the highway at 75 MPH (120 KPH). Louder than the other cars and semi-truck around us.
I was in Tokyo in August and the cicada sounds were nuts. Super loud and at first it honestly sounded like electrical equipment. IIRC I didn't figure out it wasn't electrical equipment until I went to Shinjuku Gyoen National Garden since it clearly couldn't have been electrical equipment in out in the middle of the park.
