This is a background hiss my cheap microphone records when i use my laptop. I recorded with audacity. This one has spikes of static noise every so often, sounding almost like faint voices. It's creepy in my opinion. It can also sound like water or a waterfall running in the background, or a beeping futuristic computer in a spaceship.
Background sound of people playing tennis, with cicadas and city traffic. Recorded in grant park in chicago. Equipment: zoom h4n, 80hz low cut and general limiter enabled.
A recreation of a one minute soundscape with song birds, crows, a truck stopping, background noise of car going, and a background noise of a plane overhead.