# Slo: Brown Noise — Sleep Sounds, Sound Machine > Sleep sounds and noise machine for better sleep, focus, and relaxation. (iPhone/iPad app by KARLIE ALEXIS KOWALSKA.) - Source: https://appshunter.io/ios/app/slo-brown-noise/id6739538343 (this page in markdown: same URL + `.md`) - Developer: [KARLIE ALEXIS KOWALSKA](https://appshunter.io/developer/6806982191) - Category: Health & Fitness, Music - Price: Free with in-app purchases - Rating: 4.90/5 from 63 App Store ratings · 24 written reviews indexed - Age rating: 4+ - Requires: iOS 15.6 · 72 MB - Languages: American English - Released: 2024-12-19 - Data updated: 2026-09-08 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/slo-brown-noise/id6739538343/reviews.md ## What is Slo? Slo is a brown noise and sleep sounds app for iPhone, iPad, and Mac, with 150+ curated sounds for sleep, focus, and relaxation. Play deep brown noise on its own, or mix it with rain, waves, and fan sounds — each layer with its own volume — and set a sleep timer that stops playback automatically. KEY FEATURES • Brown noise – deep, low-frequency rumble many people choose for focus and sleep • White, pink & green noise – broadband noise colors for masking background sound • Binaural beats & frequencies – binaural beats, solfeggio tones (396–963 Hz, including 432 Hz and 528 Hz) and Schumann resonance tones • Rain sounds – steady rainfall and distant thunderstorms • Waves & water – ocean waves, river, waterfall • Fan sounds – ceiling fan, table fan, airplane cabin • Nature & ambience – forest, birds, wind, fireplace, campfire, train • Sound mixing – layer sounds, each with its own volume control • Sleep timer – playback stops on its own after you drift off MADE FOR • Light sleepers who use steady sound to mask traffic, neighbors, or a snoring partner • Students and deep workers who keep brown noise or fan noise running for hours • People who wind down to binaural beats, solfeggio tones, or steady frequencies • People who use sound masking at night to make tinnitus ringing less noticeable • Anyone building a consistent wind-down routine — same mix, same timer, every night WHY SLO? A focused sound machine, not a content platform: 150+ curated sounds, a mixer with per-layer volume, and a sleep timer. No voices, no playlists — steady sound that sits in the background while you sleep, study, or work. Slo is free to download and try; the full sound library is a premium purchase inside the app. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Terms of Service: https://meltedbutter.co/terms/noise.html Privacy Policy: https://meltedbutter.co/privacy/noise.html FREQUENTLY ASKED QUESTIONS What is the best app for brown noise? Slo is built around brown noise: play it on its own, or layer it under rain or a fan sound with a separate volume for each layer, and set a timer so it stops on its own. Does brown noise help you sleep? Brown noise doesn't treat anything — what it does is mask. A steady low-frequency sound covers unpredictable noise like traffic, doors, and snoring, which is why many light sleepers keep it running at night. Can I use Slo for tinnitus? Steady broadband sounds like brown and pink noise can help mask tinnitus ringing — many people set a low volume that makes the ringing less noticeable at night. Slo is a sound player, not a treatment; persistent or one-sided tinnitus needs a medical assessment. What are solfeggio frequencies and binaural beats? Slo includes solfeggio tones (396–963 Hz, with 432 Hz and 528 Hz), Schumann resonance tones, and binaural beats — steady tones many people play for meditation and winding down. Try one with headphones and keep it if you like it. What's the difference between brown, white, pink and green noise? White noise spreads energy evenly across all frequencies (like static). Pink noise shifts energy toward lower frequencies (like steady rain). Green noise centers on the middle of the spectrum. Brown noise goes deepest — a low rumble like a waterfall or strong wind. Slo includes all of them, so try each and keep what suits you. Can I use it for studying and focus? Yes. Many users prefer brown noise or fan noise as a steady background for studying and deep work, because a constant sound gives the ear nothing new to chase. Can I mix multiple sounds together? Yes. Layer brown noise with rain, add thunder over a fan, and set each sound's volume separately to build your own soundscape. Does Slo have a sleep timer? Yes. Set the timer when you press play and playback stops automatically. Is Slo free? Slo is free to download and try; the full 150+ sound library is a premium purchase inside the app. ## Key features - Brown, white, and pink noise options - Nature sounds (rain, ocean waves) - Timer functionality - Mix multiple sounds - Offline playback - Improve sleep quality - Boost focus and concentration ## Pricing and in-app purchases Base price: Free. **Subscriptions** | Subscription | Price | Period | | --- | --- | --- | | Yearly Access | $29.99 | per year | | Monthly Premium | $5.99 | per month | **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Lifetime Access | $49.99 | one-time | | Lifetime Access | $24.99 | one-time | ## Recent user reviews (10 of 24) All indexed reviews: https://appshunter.io/ios/app/slo-brown-noise/id6739538343/reviews.md ### 4/5 — ;) *2026-06-06, version 3.102.0* Its good (i guess) ### 5/5 — Perfect Sleep & Relaxation Sounds *2026-03-13* “Brown Earth Rumble” is perfect for sleep, and the ability to layer sounds is *chef kiss* ### 5/5 — The best Brown Noise ever! *2026-02-27* This sound is perfect for sleep. I have lifetime memberships to 3 apps that cost me close to $500 all together. This has been my go to sound and app for two months… I strongly recommend this app. Nothing comes close. It makes me sleep like a baby! THANK YOU! ### 4/5 — Could be great! *2025-08-08* I love this app and use it often. I like the waterfall effect, but after a certain time it fades out then starts again. It is not looped and I cannot go to sleep by it. I’m currently using noise and have no problem with the ones I use. if you want to set the timer, it takes 4 touches to set it and get back to the main screen. Should only be 3.5 stars, but they do update it regularly and I expect these are things that will not be an issue in the future. ### 5/5 — I use it every night *2025-07-24, version 1.64* Really nice app, I use it every night to fall asleep, I especially like the feature to combine different sounds! Great job to the developer ### 5/5 — Excellent App with a very good interface *2025-07-04* A lot of sound choices. Nature, rain, water, and a lot of frequency choices and some other things I never heard of. I use this a lot, and I’m very happy with it. The developer updates often and is accessible. ### 5/5 — Great for just the right sounds for sleep. *2025-07-01* I love this app. I need some white noise to sleep and this has a great range of sounds and mixes in an intuitive layout. ### 5/5 — Chill *2025-05-13* Simple, but with plenty of good options to mix ### 5/5 — Very good app *2025-04-28, version 1.36* One of the best many sounds and functions u can play multiple sounds at the same time and setup timer . ### 5/5 — Very good sound machine *2025-03-27* I’ve tried a lot of sound machines to help me get to sleep faster and this is one of the best. The developer is still actively improving and adding features so it will only get better. It has a very nice selection of sounds to choose from. Good news! If a rooster crowing or a woodpecker hammering for lunch brings the sandman then you’re covered. The sounds can be mixed together and individual volumes can be adjusted. The campfire sound is too muted and there is no rain on a tent sound so i can relive all my family camping experiences. But i can hope for future additions to the library. You really should give this fine app a try. This helps me get to sleep faster so I am well rested for my morning woodpecker hunt. ## Frequently asked questions about Slo ### What does the Slo app do? The app provides a collection of scientifically proven sleep sounds, including various types of noise (brown, white, pink) and nature sounds like rain and ocean waves. These sounds are designed to help users fall asleep faster, improve their sleep quality, boost focus, reduce stress, and aid in meditation. ### What are the key features of this sleep sounds app? Key features include a variety of noise types like brown, white, and pink noise, as well as nature sounds such as rain, ocean waves, and waterfalls. The app also offers a timer, the ability to mix multiple sounds, and offline playback, meaning no internet connection is required. ### Is the Slo app free to download and use? The app is free to download and offers a selection of sounds. However, premium sleep sounds are available for purchase through in-app purchases, providing access to a wider range of scientifically proven audio for enhanced sleep and relaxation. ### What are the benefits of using this sleep sounds app? Users can benefit from falling asleep faster, improving overall sleep quality naturally, blocking distractions to boost focus for studying or working, reducing stress and anxiety with calming nature sounds, and enhancing mindfulness during meditation sessions. ### Can I use this app without an internet connection? Yes, the app supports offline playback. This means you can download your preferred sounds and use them without needing an active internet connection, making it convenient for use anywhere, anytime. ## Version history (last 5 releases) ### 3.132.0 — 2026-09-05 Bug fixes and improvements. ### 3.131.0 — 2026-09-04 Bug fixes and improvements. ### 3.130.0 — 2026-09-03 Bug fixes and improvements. ### 3.129.0 — 2026-09-03 Twenty-nine new sounds. Weather, mostly. Rain on a car window, light and heavy. Wind through pines, a blizzard, sleet on glass, snow underfoot. Thunder far off and a storm heard from a porch. Somewhere to be. A busy coffee shop, a quiet cafe, a library reading room. A pine forest, a riverbank and a cabin, all after dark. And things that hum. A gas boiler, an air purifier, a dryer turning. Embers with more crackle than a full fire. Handpan, kalimba, rain stick. Every one loops seamlessly. ### 3.128.0 — 2026-08-31 Bug fixes and improvements. ## Apps similar to Slo | App | Rating | Price | Category | | --- | --- | --- | --- | | [White Noise Deep Sleep Sounds](https://appshunter.io/ios/app/white-noise-deep-sleep-sounds/id1083248251) | 4.8 (206,800) | Free | Health & Fitness | | [Bedtime Fan: White Noise Baby](https://appshunter.io/ios/app/bedtime-fan-white-noise-baby/id907295335) | 4.8 (200,108) | Free | Health & Fitness | | [ColorSleep: Green, Brown Noise](https://appshunter.io/ios/app/colorsleep-green-brown-noise/id1658257567) | 4.8 (17,424) | Free | Health & Fitness | | [Sleep Sounds White Noise, Rain](https://appshunter.io/ios/app/sleep-sounds-white-noise-rain/id1453508270) | 4.8 (34,025) | Free | Health & Fitness | | [Sleepo: Sleep Sounds](https://appshunter.io/ios/app/sleepo-sleep-sounds/id1661414064) | 4.7 (399) | Free | Health & Fitness | | [Sound Machine - White Noise](https://appshunter.io/ios/app/sound-machine-white-noise/id1534157897) | 4.6 (2,143) | Free | Health & Fitness | ## More apps by KARLIE ALEXIS KOWALSKA - [Stud Finder Detector](https://appshunter.io/ios/app/stud-finder-detector/id6451046029) All apps by KARLIE ALEXIS KOWALSKA: https://appshunter.io/developer/6806982191 ## Related topics [noise machine free brown](https://appshunter.io/ios/topics/noise-machine-free-brown) · [dawid kowalski](https://appshunter.io/ios/topics/dawid-kowalski) --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-08.*