A little less noise. A little more room to think.
Presets are listening starting points, not scientifically established optima. Music, beat frequency, and comfort are personal.
Start with low device volume. Use stereo headphones with mono audio and spatial / surround processing off. Each test should sound in only one ear.
10 Hz is an exploratory relaxed-focus starting point, not a proven optimum.
The center tone sets the audible pitch; the beat frequency is the difference between ears. A 220 Hz center and 10 Hz beat gives 215 Hz left and 225 Hz right. Pitch is a comfort control, not a “healing frequency.”
Ready to load when you press Play.
Music uses original stereo FLAC sources or the optional generated score. Beats and textures are generated live. Start quietly; volume percentages are not measured sound-pressure levels.
Nine quiet palettes, from Rose Dark to true-black Noir. The scene follows your palette.
TV mode hides the interface after a few seconds. Press any remote key or tap the screen to bring it back.
There are no beat-synchronized flashes. Reduced-motion system settings override animation. TV mode hides static labels, but is not a guarantee against screen burn-in.
Gentle fade-out at the end. Pausing also pauses the timer. Changing duration starts a fresh countdown.
Save your sound, palette, and scene together.
Saved mixes stay in this browser. A share link copies the settings, not playback or remote control.
Finished sessions appear here. A rating records preference, not proof that a frequency caused an effect.
No account, tracking, microphone, or cloud storage. Backups include settings, saved mixes, and local session ratings.
A good soundscape.
Not a promise to reprogram your brain.
There is no scientifically established “best” frequency for focus or relaxation. The presets are adjustable starting points. This prototype has not been clinically tested.
A 2025 study of 80 participants found some improvements in average attention with 40 Hz beats and a 340 Hz center tone, but no convincing protection against attention declining over time. A separate 58-person study found no attention or anxiety benefit. Our music mix and listening levels do not reproduce either protocol. At 40 Hz, a clear binaural-beat sensation is not assured; perception varies.
2025 controlled study ↗ · Contrasting results ↗Alpha-band labels are not a proven recipe for a mental state. A 2023 review of 14 EEG studies found inconsistent evidence for brainwave entrainment. We use 10 Hz as an adjustable, familiar starting point—not a validated optimum.
Read the systematic review ↗A 2022 trial with 163 participants taking anxiety medication found benefits for a combined music / theta-beat intervention in a moderate-anxiety subgroup. The study was open-label, effects varied by subgroup, and music alone also helped. It does not establish 6 Hz as best or validate this app.
Read the randomized trial ↗A 2019 meta-analysis of 22 studies reported a pooled effect (Hedges’ g = 0.45) across cognition, anxiety, and pain outcomes. That supports further investigation—not one guaranteed frequency or a treatment claim.
Read the meta-analysis ↗Begin at a quiet device volume. Stop if the sound causes discomfort, dizziness, headache, or ringing. Do not use relaxation sessions while driving or doing work that needs full situational awareness. This is not a medical treatment or a substitute for care.
App volume is relative: actual listening exposure depends on your device, speakers or headphones, and listening time.
WHO safe-listening guidance ↗On iPhone / iPad, open the hosted app in Safari, then Share → Add to Home Screen. On supported desktop and Android browsers, use Install app.
Offline caching requires the full PWA folder served over HTTPS or localhost.
Tap Play once to enable audio. Mobile browsers may suspend synthesized audio when the screen locks or the app is backgrounded; dependable lock-screen playback is not promised. TV-browser support for full screen, installation, and wake lock varies.
Space: play / pause. F: TV mode. M: mute. Escape / TV Back: close controls, then leave TV mode. Arrow keys move focus; Left / Right adjusts a focused slider. Enter / OK activates a button.
The app does not pair a phone as a TV remote. Use the TV remote, an attached keyboard, or the TV browser’s pointer. No Spotify / YouTube account is needed.
Undertone · 0.2 · Research checked September 19, 2026. Built with native Web Audio and Canvas. Original FLAC sources are lossless; mixing, browser resampling, the OS, and your output device can alter the signal. Playback is not claimed to be bit-perfect. Music files are hosted with the app. Research and artist links open externally.