Quell: Deep Focus

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.