Two ever rising shepard tones rising at different rates overlaid by a pulsing hiss. This is a sound effect used to indicate a steadily approaching peril. It can be seamlessly looped.
6 minutes 20 secs of lunch time kitchen noises with cooking eggs, microwave open close and use, gas hiss, mugs clings, light washing up noises open drawers reset pans, cups and mugs.
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.
Bubbling sounds on exhale and regulator hiss during inhale. There is briefly a whizz sound from a rigid inflatable boat propeller passing nearby. Recorded with a contour+2 camera.