Brainwaves: delta, theta, alpha, beta and gamma
Neurons communicate through tiny electrical signals. When large groups of them fire together, they produce rhythms that can be recorded from the scalp with an electroencephalogram (EEG). These rhythms are grouped into bands by speed, measured in hertz (Hz: cycles per second).
There’s no single “state” at any given moment: the brain produces several bands at once, and what changes is which one dominates.
The five bands
| Band | Approximate range | Associated with |
|---|---|---|
| Delta | 0.5–4 Hz | Deep sleep, restorative rest |
| Theta | 4–8 Hz | Drowsiness, daydreaming, deep meditation, imagination |
| Alpha | 8–12 Hz | Relaxed wakefulness, eyes closed, calm attention |
| Beta | 12–30 Hz | Active attention, thinking, conversation, work |
| Gamma | above 30 Hz | Intense processing, integrating information |
The boundaries vary slightly from source to source; treat them as reference points, not exact borders.
What does this have to do with music?
Brainwaves are very slow compared with audible sound, which starts at around 20 Hz. So music doesn’t “broadcast” alpha or theta waves directly. What binaural beats and isochronic pulses do is create a slow rhythm inside the sound, in the same range as these bands.
Solfeggio frequencies (174, 285, 396, 417, 528, 639, 741, 852 and 963 Hz), on the other hand, are audible tones that tradition links to specific intentions. They’re two different ideas that often share the same piece.
A practical way to choose
- For sleep: slow, low pieces in the delta or theta range. Try Earth Rest · 174 Hz.
- For meditation: theta or alpha, with little melody and a slow tempo.
- For focus: alpha or gentle beta, with no vocals. Try Clarity · 732 Hz.
What works best is what feels right for you: listen, notice how you feel and adjust.