Octave (2:1)

The doubling of frequency that every musical culture hears as "the same note, higher".

Core Principles & Analysis

• A note and its octave share every other harmonic, which is why they fuse so completely.
• Octave equivalence — treating doubled pitches as one class — appears across nearly all musical cultures.
• Equal temperament slices the octave into twelve identical semitone steps.

Specifications & Metrics

• FREQUENCY: 2:1 ratio