Delta

Delta waves are the large, slow oscillations that dominate EEG readings during slow-wave sleep — the deepest stage of the night, when the body does most of its physical repair and the brain clears metabolic waste. You're not conscious of delta; if delta is dominant, you're almost certainly not aware of anything at all.

What people use it for

Delta-range beats (roughly 1–4 Hz) are the standard choice for sleep-focused sessions. The theory is that a slow, steady rhythm gives the auditory system something monotonous to settle into as you wind down. Whether it actively drags brain activity toward sleep or simply works as a very boring, very consistent lullaby is an open question — and honestly, either mechanism is fine if you fall asleep.

In the studio

• Set the beat between 1–4 Hz (the Sleep preset uses 3 Hz)
• Keep the carrier low and soft — 100–200 Hz feels less intrusive at night
• Brown noise layered underneath masks household sounds well
• Keep the volume genuinely quiet; louder is not deeper

Worth knowing

You can't force sleep with audio, and delta beats are not a treatment for insomnia. If sleep problems are persistent, that's a conversation for a doctor, not a tone generator.