The short answer
Play sleep sounds long enough to carry you through falling asleep — for most people that's somewhere between thirty and ninety minutes — and let them fade out after. Keep them all night only if your environment stays noisy after midnight. What you should never do is let the sound stop abruptly: a sudden silence in the middle of the night is itself a disturbance.
Why the ending matters more than the duration
Your sleeping brain keeps monitoring for change. A sound that cuts out instantly is a change, and it can pull you toward wakefulness — the audio equivalent of someone switching off a light you didn't know was on. This is why Calming Galaxy's sleep timer doesn't stop the audio: it fades it out gradually, so the room gets quieter slowly enough that you never notice the moment it happens.
The case for the timer
Once you're past the light stages of sleep, your brain is far less reactive to ordinary household noise — which means the masking job is mostly done. A timed fade gives you the benefit where it counts, then hands the night back to silence. It also saves battery, keeps the room quiet for a partner who sleeps later than you, and means one less thing playing when the alarm goes off.
- Start with 45–60 minutes if you usually drift off within half an hour.
- If you regularly hear the fade begin, extend it — you should be asleep before it matters.
- If you wake when it ends, the fade is your friend: it should be imperceptible, so check the volume is low.
The case for all night
Some environments never quiet down: street traffic that peaks at 2 a.m., a partner who comes to bed late, a dog who announces every passing fox. If your noise problem is genuinely all-night, an all-night sound at low volume is reasonable — the key word being low. Continuous loud audio isn't the goal; a soft, steady backdrop is.
Volume matters more than duration
However long you play sounds, keep them quiet — about the level of a whispered conversation, and place the device away from your pillow rather than beside your ear. You're trying to raise the floor of the room's sound just enough that sudden noises don't stand out against it. If you can clearly make out details in the sound from your pillow, it's probably louder than it needs to be.
Naps are a different game
For daytime naps, a timer isn't optional — it's the whole point. Set twenty to thirty minutes, let the sound carry you down quickly, and let the end of the audio bring you back before you sink into deep sleep that leaves you groggy.
How to find your number
Start at 45 minutes for a week. If you're reliably asleep long before the fade, you can experiment with shorter. If you lie awake past it, extend to 90. And if outside noise wakes you at 5 a.m. regardless, switch to all-night at low volume. Two weeks of small adjustments will tell you more than any guide — including this one.
Hear it for yourself
These guides are easier to act on than to read. The sounds they reference each have their own page — the ones marked Free play right there on the site.
