Solar Cycle (11-year)
Directly measured, standardized, or well-supported in mainstream scientific or technical literature.
The underlying cycle is measurable, but the audible tone is an octave-transposed mapping used for comparison, listening, and practice rather than a naturally audible emission.
Review the evidence modelThe approximately 11-year solar cycle governs sunspot activity, solar flares, and geomagnetic storms. The full magnetic cycle is ~22 years (Hale cycle).
Sources
Used for atmospheric resonances, Earth-ionosphere cavity behavior, and related geophysical frequencies.
W.O. Schumann (1952) and later geophysical literature.
Octave Ladder
Every audible octave of this frequency — the same tone, higher and lower.
Nearby in the Atlas
Entries within ±35 cents of this tone when reduced to the same octave — candidates for pairing or comparison.