THE SHORT VERSION
A sleep timer lets background sounds end on their own so you do not have to stay awake to stop them. The fade matters more than you might expect, and iOS keeps audio running after the screen locks as long as the app is set up correctly.
Why a sleep timer matters for background sound
Background sound for sleep works best when it covers disruptive noises during the period you are falling asleep. Once you are in deeper sleep stages, you generally need it less. Running sound all night is not harmful on its own, but it drains your battery and can become a disturbance if your sleep lightens toward morning.
The National Heart, Lung, and Blood Institute recommends keeping your bedroom quiet and using the hour before bed for quiet, wind-down time. A sleep timer fits that pattern: the sound helps you transition, then gets out of the way.
There is no research showing a precise ideal duration. Thirty to sixty minutes is a common starting point. If you tend to fall asleep quickly, fifteen minutes may be enough. If it usually takes you longer, try a longer window and adjust from there.
Using the sleep timer in Soothescape
Soothescape includes a built-in sleep timer. Open the app, build or load a mix of up to four layered sounds, then tap the timer control. Choose a duration and start the countdown. When the timer finishes, your mix fades out and playback stops.
The fade is worth paying attention to. An abrupt stop can feel jarring, even if you are half asleep. Soothescape fades the audio gradually so the transition is smooth rather than sudden.
Because Soothescape is an offline app, the timer and playback do not depend on a network connection. You can use it in airplane mode, on a flight, or anywhere you do not have Wi-Fi. Your saved mixes and timer settings are all stored locally on your device.
What happens when your iPhone screen locks
When you lock your iPhone or the screen dims automatically, a properly configured audio app keeps playing. iOS allows this through a background audio mode that developers declare when building the app. The app sets its audio session to a playback category, which tells iOS the sound is intentional and should continue.
Apple's developer documentation confirms this behavior: apps that set the audio session category to playback and declare the background audio capability will continue producing sound when the screen locks. This is the standard approach for any app designed to play audio while you are not actively looking at the screen.
If you ever find that an audio app stops when your screen locks, check two things. First, make sure Low Power Mode is off, since it can throttle background activity. Second, confirm that Background App Refresh is enabled for the app in Settings. These are iOS-level settings, not something the app itself controls.
The built-in iPhone timer as a backup
iOS has a lesser-known feature that works with any audio app. Open the Clock app, go to Timer, set your desired duration, then tap When Timer Ends and scroll to the very bottom. You will see an option called Stop Playing. Select it, tap Set, and start the timer.
When the countdown reaches zero, iOS stops whatever audio is currently playing and locks the device. This works across apps, not just Apple Music. It is a useful fallback if an app does not have its own timer.
One thing to remember: this replaces your normal timer alert sound. If you later set a cooking timer and forget to switch back to a ringtone, it will silently stop your media instead of beeping. After using Stop Playing, go back and choose a regular alert tone for your next non-sleep timer.
Choosing a duration that works for you
Start with a duration slightly longer than you think you need. If you usually fall asleep in twenty minutes, try thirty. The goal is for the sound to still be playing when you lose awareness, not for it to cut out while you are still trying to settle in.
If you wake up and the sound has already stopped but you feel fine, the duration is probably right. If you wake up and wish it were still playing, try adding fifteen minutes. There is no single correct answer here. Sleep onset varies by person and even by night.
Keep in mind that sound is not a sleep treatment. The NHLBI emphasizes consistent sleep and wake times, a cool and dark room, and avoiding caffeine and bright screens before bed. Background sound can be part of a wind-down routine, but it works alongside those basics, not instead of them.
Volume and fade considerations
Set your volume before you start the timer, not after. A comfortable listening level for sleep is typically quieter than what you might choose during the day. The sound should be loud enough to mask a dripping faucet or passing car, but not so loud that it becomes the dominant thing in the room.
The National Institute on Deafness and Other Communication Disorders notes that prolonged exposure to sounds at or above 85 decibels can damage hearing over time. Normal conversation is around 60 to 70 decibels. For sleep, you are generally well below any risk threshold, but it is worth checking if you use headphones or earbuds, where the sound is closer to your ears.
A gradual fade at the end of the timer is gentler than an abrupt cutoff. If you are using the iPhone Clock timer with Stop Playing, the stop is immediate rather than gradual. An in-app timer with a built-in fade, like the one in Soothescape, handles this more smoothly.
Who this may not suit
If you have a diagnosed sleep disorder such as insomnia or sleep apnea, a sleep timer on a sound app is not a substitute for treatment. Talk to a doctor about what is appropriate for your situation.
Some people find that any background sound, even a quiet one, makes it harder to fall asleep. If you have tried a few sessions and the sound consistently keeps you awake rather than helping you relax, it may simply not be for you. That is a normal variation in preference, not a failure.
Tinnitus is another area where people sometimes turn to background sound. While masking can provide temporary relief for some, the research landscape is mixed, and a sleep timer that stops the sound mid-night could be counterproductive if masking is the goal. An audiologist can offer guidance specific to your situation.
Sources & further reading
Research checked September 7, 2026. This article is written by the makers of soothescape and has not been medically reviewed.