Entrain
The beat is not in the sound
Each ear gets one steady tone. Press each one and watch its half of the line.
Neither half pulses. The slow pulse you hear forms in your brain, which is why it needs headphones.
Drawn slower than life. Added is what speakers play. Your auditory system does respond to the beat. Whether the wider brain follows is unsettled: one review found 5 studies for, 8 against and 1 mixed.
The band's thickness is the beat, and each gap starts a new phase. Drag around the ring to any moment.
Brain rhythms are sorted into bands by speed. Playing a beat at that speed does not mean your brain goes there.
Linked in research to
Sessions that rest here
Evidence, rung by rung
Our reading of the studies, in order, not a score. The best so far is modest calm, especially around medical procedures. Nothing reaches the top.
Each dot is one session's change in calm, on a 1 to 5 scale. Lines mark the averages, and the bar at the bottom is the likely range.
Test it on yourself
Each time, the app plays the real beat or the same tone with no beat, and hides which. You rate your calm before and after.
Imagine the beat does
Run it a few times on Nothing. Chance alone can look like an effect, which is why the answer is a range, and why one good session proves little.
There is no side by side preview of the two sounds here. Learning the difference first would spoil your test.
Every source we cite
Sources and corrections
We checked these against Europe PMC, mostly by reading abstracts rather than full papers.
What we got wrong
Found in our review of 17 October 2026 and fixed on 2 November 2026.
If you hear nothing
All three work and you still feel no change? That is a common result. Effects often shrink against careful controls, and it may not do much for you.
Using it safely
On the screen
Nothing flashes at the beat rate. The moving line is thin, keeps one brightness, and leaves the beat out of its movement. We measure that.
On your device
Your blind test results stay on this device.