# Quell: Deep Focus — 40 Hz sound for deep focus > 40 Hz sound for deep focus (iPhone/iPad app by Oleksandr Pavlov.) - Source: https://appshunter.io/ios/app/quell-deep-focus/id6775249705 (this page in markdown: same URL + `.md`) - Developer: [Oleksandr Pavlov](https://appshunter.io/developer/6775249707) - Category: Health & Fitness - Price: Free with in-app purchases - Age rating: 4+ - Requires: iOS 17.0 · 58 MB - Languages: American English - Released: 2026-06-09 - Data updated: 2026-06-28 - User reviews in markdown: https://appshunter.io/ios/app/quell-deep-focus/id6775249705/reviews.md ## What is Quell? Quell is a deep-focus app with one job: help you sit down and do one undivided thing. No streaks. No badges. No feed. You tap Begin, a calm arctic ring starts counting up, and a 40 Hz binaural beat plays underneath. When you are done, you end. That is the whole ritual. WHY 40 Hz 40 Hz is the gamma band — the brain rhythm tied to attention and memory, and the most-studied frequency in sound-based focus research. Quell generates it live: two pure tones, one slightly different in each ear, that your brain fuses into a single 40 Hz pulse. WHAT IT DOES - A 40 Hz binaural beat, generated live on your device. Two pure tones on a deep, warm carrier (130 Hz left, 170 Hz right). It needs stereo headphones to create the beat. - An optional coach voice. Short, grounded lines, spaced minutes apart, that nudge you back when your attention drifts. It is sports-psychology self-talk, not generic meditation, and it is a natural recorded voice, not a robotic one. - Optional music under the beat. Four moods of original, AI-generated tracks (lofi days, lofi night, global beats, ambient) that sit quietly beneath everything. Off by default. - A count-up timer. No fixed length, no pressure. The session lasts as long as you stay. THE SCIENCE, HONESTLY We lead with 40 Hz because the research is real — it is the gamma approach popularized on the Huberman Lab podcast. A 2022 meta-analysis found binaural beats gave a small but significant lift to attention and memory, and a 2025 study confirmed that a 40 Hz beat measurably entrains the brain while improving attention. But we will not oversell it: not every study agrees, and the effect varies from person to person. Treat the 40 Hz tone as a low-risk way to settle into deep work, not a guarantee. DESIGNED TO DISAPPEAR Quell is dark, still, and quiet on purpose. The only bright thing is the ring. It keeps playing while your screen is off, with controls on the lock screen, so you can put the phone down and work. PRIVATE BY DESIGN Everything runs on your device. No account, no sign-in, no tracking, no analytics, no servers. Your settings stay on your phone. FREE AND PAID The 40 Hz beat and the timer are free, forever. A single one-time purchase unlocks the music moods and the coach voice. Pay once, it is yours. No subscription. Quell. Quiet the noise. ## Pricing and in-app purchases Base price: Free. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Quell Unlock | $9.99 | one-time | ## Version history (last 3 releases) ### 1.2 — 2026-06-10 Refreshed our App Store screenshots to show Focus for ADHD — the noise-forward focus mode for ADHD brains — plus breathing, felt-time markers, and the coach. No changes to the app itself in this version. ### 1.1 — 2026-06-09 Focus for ADHD: a noise-forward session with a warm brown-noise bed, tuned for ADHD focus (the 40 Hz beat is one tap away). Felt-time markers: a soft chime every 25 minutes so long focus sessions are easier to feel. Body-double coach: a more present, co-working voice (with Unlock). Smoother pause and resume. ### 1.0 — 2026-06-09 No release notes. --- *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 2026-06-28.*