Slo vs BetterSleep (2026): Mixer or Full Sleep App?

Slo fits if you want to layer ambient sounds yourself, with 200+ sounds and 89 of them free, any number of layers with a volume each, and a timer from 15 minutes to 24 hours that fades out before it stops. BetterSleep fits if you want one app for the whole night, with 500+ sounds and melodies, SleepTales, hypnosis and sleep tracking.

The short answer: if the only thing you want at bedtime is a sound you can set once and get back the same way, Slo covers that, and 180 of its sounds play free in a browser with no account. If you also want narrated SleepTales, meditation, hypnosis and a record of how you slept, BetterSleep is the app built around all of that. They answer different questions, so neither one wins in general.

Everything here about BetterSleep comes from its official product and support pages, read on July 31, 2026; nobody here installed it. Slo is ours, and the numbers for it come from the app source, version 3.132, on September 14, 2026. Neither app can guarantee better sleep.

Slo vs BetterSleep at a glance

If you care most about…	Better fit	Why
Mixing a few ambient layers yourself	Slo	You add as many layers as you like, set a volume on each one, and the app brings that balance back next time.
A large sound and music catalog	BetterSleep	Its documentation lists more than 500 sounds and melodies.
Stories, meditation, or hypnosis	BetterSleep	All three sit in the sleep-content library it documents.
Sleep tracking and recorded sleep sounds	BetterSleep	It ships tracking and a sleep recorder next to the audio.
Trying the workflow before downloading an app	Slo	You can play 180 sounds at slonoise.com with no account and nothing to install.

This page is about which product fits you. Sound preferences differ from person to person, and no app here can diagnose a sleep disorder or fix one.

What is the main difference?

Slo plays recorded sound and lets you mix it. The app ships 200+ recorded sounds and keeps 89 of them free for good, including 22 noise recordings across seven colors, 5 of which are brown. You can stack any number of layers, each with its own volume, and the app remembers the balance for every combination you build, so last night’s mix comes back the same tonight. You can export a saved mix to a file and bring it into the app on another device. The sleep timer runs from 15 minutes to 24 hours, and the sound fades out over up to 2 minutes before it stops. On iPhone and Android, playback keeps going once the screen is dark, because it runs as a background audio service. Each sound downloads on first play and stays on the device, so in the app a saved mix works with no connection. The full library is a monthly subscription, a yearly subscription or a one-time lifetime purchase. At slonoise.com, 180 sounds play free with no account.

Slo also leaves out most of what BetterSleep does. There are no sleep stories, no guided meditation, no sleep tracking, no adaptive audio, no alarm, no recorder and nothing spoken.

BetterSleep is closer to an all-in-one sleep app. Its official support material lists sounds and melodies, SleepTales, meditation and hypnosis, sleep tracking, a smart alarm, reminders, and a sleep recorder. Its mixer can combine up to 15 sounds, one music track, and one brainwave track in the app.

So the question is how much product you want sitting around the audio.

Can I mix my own sleep sounds?

You can in both apps, and the difference is where mixing sits. In Slo it’s the main event: add the layers you want, set a volume on each, and pull out anything that keeps catching your attention. The app stores that balance per combination, so a mix you liked in March sounds the same in September, and you can try the whole flow in a browser before you install anything.

BetterSleep’s mixer lives inside a much larger app. Its official getting-started guide documents a high ceiling, up to 15 sounds plus one music and one brainwave selection, which suits you if you enjoy detailed combinations. When all you want is a steady background, that’s more choice than the job needs.

If you’re not sure which suits you, build one two-layer mix, keep it for several nights, and change one layer at a time. More layers don’t make a better night’s sound.

What BetterSleep’s sound library includes

BetterSleep documents more than 500 sounds and melodies and more than 100 SleepTales, along with guided formats such as meditation and hypnosis. If a voice belongs in your bedtime routine, that catalog is the reason to pick it.

Slo’s side is 200+ ambient sounds with 89 free, browser presets, a player, a mixer and a timer that runs to 24 hours. Nobody narrates anything, and there’s no meditation or sleep coaching in it.

Does either app track your sleep?

Only BetterSleep. It includes sleep tracking, a recorder, and a smart alarm, so if you like reviewing your patterns in the morning, or want to hear what the room did overnight, those tools sit beside the audio.

Slo tracks nothing and records nothing. You lose the dashboard, and in exchange the app never asks for the microphone. Both are reasonable things to want; you just can’t have them in the same app here.

Platforms and access

BetterSleep’s official guide lists apps for iOS and Android. Slo runs on iPhone, Android and Mac, and 180 of its sounds play in a browser with no account. The browser side is the smaller one, with timers that stop at 60 minutes, while the app timer runs to 24 hours.

Exact prices move by region, so this page doesn’t print them. BetterSleep says its plan options and prices can differ. Slo sells the full library as a monthly subscription, a yearly subscription or a one-time lifetime purchase, so the lifetime option is the one that lets you stop paying.

Which should you choose?

Choose Slo if:

• Ambient sound with a volume on every layer matters more to you than a whole sleep program.
• You want a timer that runs to 24 hours and fades out over up to 2 minutes.
• A one-time purchase appeals to you more than a monthly bill.
• You’d like to try 180 sounds free in a browser before you install anything.

Choose BetterSleep if:

• You want stories, meditation, hypnosis, tracking, and a recorder under one icon.
• A catalog of 500+ sounds and melodies is worth paying for.
• You enjoy building detailed mixes with many layers running at once.

Frequently asked questions

Does BetterSleep have a sound mixer?

Yes. Its official getting-started guide says the app can combine up to 15 sounds, one music track, and one brainwave track.

Can I use Slo without downloading an app?

Yes. At slonoise.com, 180 sounds play free with no account, every mix layer keeps its own volume, and the timer offers 15, 30 or 60 minutes. The app goes further, with 200+ sounds and a timer that runs to 24 hours.

Which app has sleep tracking?

BetterSleep does. It documents sleep tracking and a sleep recorder. Slo has neither and records nothing, so all it does is play the sounds you pick until the timer ends.

Is Slo or BetterSleep cheaper?

That depends on the checkout you see. Slo keeps 89 of its 200+ sounds free for good and sells the full library as a monthly subscription, a yearly subscription or a one-time lifetime purchase. BetterSleep says prices vary by plan and market, so compare both in your own region.

Official sources checked July 31, 2026

• BetterSleep: feature overview
• BetterSleep: getting-started guide and mixer limits
• BetterSleep: plans and pricing guidance
• Slo app source, version 3.132 (sound list, timer, fade-out and store products), and the slonoise.com sound catalogue, reviewed September 14, 2026

Related guides

• Best sound mixing apps in 2026
• How to use sound mixing
• How to create a sleep soundscape
• Best sleep sound apps in 2026

Filip Kowalski is the developer of Slo and writes about sound, sleep, and focus.