The Bands
The brainwave bands, explained
Five frequency bands, what the research says about each, and what it does not. Every page names its sources where they exist and says plainly where the evidence is thin.
0.5–4 Hz · Sleep
Delta waves
The slowest band, and the signature of deep sleep. Not something you enter while awake.
4–8 Hz · Drift
Theta waves
Between sleep and waking. It appears in drowsiness and in hard concentration, which is why one feeling does not describe it.
8–13 Hz · Calm
Alpha waves
The rhythm of relaxed wakefulness, and the band with the most consistent evidence behind it. The 10 Hz session sits in the middle of it.
13–30 Hz · Alert
Beta waves
The background rhythm of being awake. More of it is not better, and no session here uses it.
30–100 Hz · Focus
Gamma waves
The fastest band, and the hardest to record cleanly. The 40 Hz session sits low in it.