What makes Cavern read as an enclosed space rather than open water is the reverb decay: twelve seconds, same as the rest of deep sleep, but paired here with an actual cave texture instead of waves, so every hum sounds like it's bouncing off rock a few feet past where you can see. The occasional drip sits low in the mix on purpose; most nights you won't consciously register it, you'll just feel like the room got bigger.
It's brown noise and cave ambience layered under a slow drone, built as sleep music for anyone who finds open, airy presets like Abyss or Ocean Deep a little too vast to settle into. Cavern feels contained instead, like being somewhere sheltered rather than somewhere endless. It's the version of deep sleep sound for people who sleep better with walls around them, even imagined ones.
The drip and the drone are both generated on your device rather than played back from a file, so the pattern of drips never lines up the same way twice across a whole night. There's no fixed loop length for your ear to eventually catch.
StillTune composes endless, ever-changing music for sleep, focus and relaxation. Real melody and instruments, generated live, with no audio files. Explore more sounds.