What makes a sleep sound "deep"
Sounds people describe as deep share two properties: most of their energy is in the low frequencies, and they change slowly. Brown noise, distant thunder, ocean swell and a big fan all fit. The low end covers the thumps and rumble of a daytime street; the slow movement stops the sound from feeling like a mechanical hiss.
ShiftSleep AI leans on exactly those generators. The Deep Sleep preset uses brown noise for the floor and rain for a little texture on top, and the mixer lets you swap rain for ocean, add thunder underneath, or bring in a fan.
Sounds in the deep end of the catalog
- Brown Noise — the anchor of the Deep Sleep preset
- Ocean — rolling waves with a slow swell
- Thunder — distant rumbles with sparse cracks
- Rain — soft rainfall for texture over a noise bed
- Fan and AC — steady, low mechanical hum
- Wind and Forest — gusting air and canopy hush
Play, fade, log
Tap Deep Sleep on Home and it starts with a two-second soft ramp. Pick a timer — 15, 30, 45, 60 or 90 minutes, or all day — and the sound fades out near the end rather than stopping. If you have a shift profile set up, the same screen shows your sleep window and lets you log the day sleep or a recovery nap with one tap, so your streak and insights build from real sessions.
No loops, no ads, no signal needed
Every deep sleep sound is generated live. There is no file that ends and restarts, no ad break, and no streaming: the sounds work in a hospital basement break room as well as at home. Free includes the core sounds, a two-layer mixer and the timer; Premium unlocks the full catalog, four layers and the AI helper that can build a mix from a description of your rota.
ShiftSleep AI supports rest and routine with sound and simple logging. It is not medical advice and does not diagnose or treat sleep disorders. If your sleep problems persist, talk to a clinician.
Frequently asked questions
Which sound is best for deep sleep?
There is no single answer; it depends on what is waking you. Brown noise and thunder cover low rumble; rain and fan cover a broader band. Deep Sleep combines brown noise and rain as a starting point, and the mixer lets you adjust from there.
Do deep sleep sounds turn off automatically?
Yes, if you set a timer. The sound fades out softly near the end. You can also run it all day.
Is the Deep Sleep preset free?
Yes. Deep Sleep and the core generators are part of the free tier.