[quesera]

Absent humans, this still applies:

> The trend is higher sound levels in wetter areas with more vegetation. This is due to the sounds of wind blowing through vegetation, flowing water, and more animals (especially birds and frogs) vocalizing in more fertile locations.

[shmageggy]

I find those sorts of natural sounds to be way less annoying and offensive than machine-originated sounds, even at equal decibel levels. Perhaps it’s because of a learned/cultural associations, but I’d bet there’s something inherently annoying to most manmade sounds, probably due to the periodic nature of motors, fans, etc. I’d be interested in the above suggested diff map showing (approximately) machine-originated sound levels.