Pure Sound: how it sounds

How this course sounds — the science

Every session is a layered binaural program: several tone pairs, one tone of each pair per ear, over a soft noise bed. The numbers below come straight from the session designs.

The course in numbers

• Beats from 0.75 to 40 Hz, covering the delta, theta, alpha, beta, gamma bands.
• Carrier tones from 45 to 804 Hz.
• Up to 6 tone pairs sound at once.
• Slower beats sit on lower carriers in 113 of 155 pair comparisons, the ordering measured in the reference set.
• Tone level changes by -3.5 dB per octave of carrier, so the higher tones sit quieter.
• 5 sessions end with a beta-range wake-up block.
• Noise bed: brown, independent in each ear. Its level and brightness move on a slow 10-second cycle.

Tuning and carriers

The Tuning setting in the editor re-pitches the carrier tones and never the beats.

• Standard: carriers from 45 to 800 Hz, as designed.
• A=432 Hz: every carrier 31.8 cents lower, from 44.2 to 785.5 Hz.
• Solfeggio: carriers snap to 174, 285, 396, 417, 528, 639 Hz inside their own range; the lowest and highest carriers keep their pitch.

Tunings and tones are offered as sound to explore, with no promise of effects. Read what the research says about frequencies.

The method

The sessions use the layered binaural method described in our research note. We measured a reference set of guided programs and generate every bed from those statistics, never from a recording.

• Carrier–beat ordering: slow beats ride on low carriers and faster beats on higher ones, and each tone's level falls with carrier frequency (stacking and level).
• Each phase moves the stack to a new band and crossfades smoothly into it (beats by stage).
• A noise bed shaped to the measured spectrum keeps the tones soft and masks small sounds around you (noise).
• The voice sits about 12 dB above the bed, and gentle mastering leaves the stereo beats intact (how your audio is made).

Session by session

Questions