How to use a sleep timer with sleep sounds (and why not to play them all night)

What sound is actually for

The best-supported use of sleep sound is masking: raising the steady floor of what you hear so that a door, a car or a neighbour’s television stands out less. That matters most in the twenty minutes while you are falling asleep, when a tired brain is still scanning for threats. One small laboratory study found broadband sound cut sleep-onset time by about 38% in a noisy setting. A 2021 systematic review of continuous noise as a sleep aid found the overall evidence low in quality — some studies show benefit, some show disruption. Sound is a tool for the start of the night, not a treatment.

Why a timer

Once you are asleep the sound has done its job. Left running, it has hours in which to do harm: a loop with an audible join, a track that ends, a phone notification over the top, a change in level as the room goes quiet. Each is a cue that can pull you up out of light sleep. The Northwestern pink-noise study that gets quoted as “noise deepens sleep” used precisely timed pulses from a device reading the brain’s waves — not a phone playing a track until morning.

Thirty to forty-five minutes is the practical setting: it covers the ten to twenty minutes most people need to fall asleep, plus a margin for a slow night. If you wake at 3 am and cannot settle, start it again for another thirty.

How loud

Lower than most people set it. If you cannot hold a conversation over the sound, it is loud enough to be a stressor over a night rather than a comfort. With masking, the point is to blur sudden sounds, not to drown the room; a level that disappears into the background within a minute is about right.

Layering sounds

Steady, broadband sounds do the masking: rain, surf, a river, a fan. They sit close to pink or brown noise on the spectrum and are easy on the ear. Intermittent sounds — birds, distant voices, a crackling fire, thunder — add texture and can be lovely at the start of the night, but each is a small event that attention can latch onto. The sensible mix is one steady bed at low volume, one texture even lower, and the intermittent sounds off or barely audible. In the app linked from this site, each scene has six sounds with independent volume, which is what makes that mix possible; the Rainy Day scene’s “little rain” plus “forest rain”, with everything else off, is the plain default.

Fitting it into the night

The bedtime pages give lights-out times that end on a full cycle. The timer starts at lights out; the cycle arithmetic already includes fifteen minutes to fall asleep, so a thirty-minute timer runs past the moment the first cycle should begin and then stops. If the sound is still playing when you notice you are awake, that is the twenty-minute mark — the point at which getting up does more than lying there.

Questions people ask

Is it bad to sleep with sound on all night?

Not dangerous at low volume, but the evidence for benefit is weak and a sound that changes or stops can wake you. A timer avoids both.

What volume should sleep sounds be?

Low enough to hold a conversation over. The goal is to blur sudden noises, not to drown the room.

Which sounds work best for sleep?

No study crowns one. Steady, broadband sounds — rain, surf, a fan — mask well. Intermittent sounds like birds or voices are pleasant but can catch attention; keep them low or off at night.