Sources

Each note is the one below it multiplied by the twelfth root of two. A4 is fixed at 440 Hz by ISO 16.

ISO 16:1975, Acoustics — Standard tuning frequency (Standard musical pitch).

Where visible light and ultraviolet begin and end. The authorities do not agree exactly on the limits.

CIE International Lighting Vocabulary, terms 17-21-003 (visible radiation) and 17-21-008 (ultraviolet radiation). ISO 21348. BIPM, definition of the candela at 540 THz (555 nm).

Where the named radio bands begin and end. Broadcast bands differ by region.

ITU-R Recommendation V.431, Nomenclature of the frequency and wavelength bands used in telecommunications. FCC, 47 CFR 73.14 (AM) and 73.201 (FM). FCC, 47 CFR 15.247 (2400–2483.5 MHz).

Which tuning forks are used for which clinical test.

British Society of Audiology, Recommended Procedure: Rinne and Weber tuning fork tests (2022).

The international standard that sets A4 at 440 Hz.

ISO 16:1975, Acoustics — Standard tuning frequency (Standard musical pitch). Supersedes ISO/R 16:1955.

Cousto’s shorter text, where the 351 nm figure is attributed to a personal communication from F.-A. Popp.

Hans Cousto, Die Oktave, p. 38 and endnote 20. Planetware.

The book that sets out the method of octave doubling. Cited as the source of Cousto’s claims, not as evidence for them.

Hans Cousto, Die kosmische Oktave (Synthesis Verlag, Essen, 1984). English edition: The Cosmic Octave (LifeRhythm, Mendocino, 1988).

The instrument’s first appearance in writing, and the legend that Pythagoras invented it.

David Creese, The Monochord in Ancient Greek Harmonic Science (Cambridge University Press, 2010).

The source of the five “structures of consciousness” described on the Consciousness page.

Jean Gebser, Ursprung und Gegenwart (1949/1953). English: The Ever-Present Origin, translated by N. Barstad and A. Mickunas (Ohio University Press, 1985).

The standard definitions of the delta, theta, alpha, beta and gamma bands.

N. Kane et al., Clinical Neurophysiology Practice 2 (2017) 170–185.

The prediction, the first measurement, and a later summary of the mode frequencies.

W. O. Schumann, Zeitschrift für Naturforschung A 7 (1952) 149–154. M. Balser and C. A. Wagner, Nature 188 (1960) 638–641. F. Simões, R. Pfaff and H. Freudenreich, NASA Goddard Space Flight Center (NTRS 20120000051).

Heart rate, breathing rate, the daily clock and the sleep cycle.

C. A. Czeisler et al., Science 284 (1999) 2177–2181. N. Kleitman, Sleep 5 (1982) 311–317. J. Moses et al., Nature 265 (1977) 360–361. A. Zaccaro et al., Frontiers in Human Neuroscience 12 (2018) 353.

Cited for the ranges in which higher gamma activity was reported: 25 to 42 Hz, in 8 practitioners and 10 others (2004), and 60 to 110 Hz (2017).

A. Lutz et al., Proceedings of the National Academy of Sciences 101 (2004) 16369. C. Braboszcz et al. (2017).

Cited for what the experiments used and what they found.

H. F. Iaccarino et al., Nature 540 (2016) 230–235. A. J. Martorell et al., Cell 177 (2019) 256–271. M. Hajós et al., Frontiers in Neurology 15 (2024) 1343588. R. M. Ingendoh et al., PLoS ONE 18 (2023) e0286023.

A randomized trial in 100 people. The sessions combined recorded 528 Hz audio with bowls and gongs, so the parts cannot be told apart.

H. Ravikumar and S. Sathyanarayanan, Cureus 18 (2026) e115693.

The history of the 432 Hz proposal, and the two small studies that compared 432 with 440 Hz.

E. Lockhart, Nineteenth-Century Music Review 22 (2025) 344–360. D. Calamassi and G. P. Pomponi, Explore 15 (2019) 283–290. D. Calamassi et al. (2022), PMID 35545982.

Cited for the resonances it reported at the Hypogeum: 114 Hz, and 68 to 70 Hz.

P. Debertolis et al. (2015).

Cited for what was measured and what was tested.

R. G. Jahn, P. Devereux and M. Ibison, Journal of the Acoustical Society of America 99 (1996) 649–658. I. A. Cook, S. K. Pajot and A. F. Leuchter, Time and Mind 1 (2008) 95–104. R. Till, Antiquity 91 (2017) 74–89.

Dating of the instrument from depictions in rock art.

D. Wesley, T. Jones and R. Whitau, chapter 2 of The Archaeology of Rock Art in Western Arnhem Land, Australia (ANU Press).

One study in nine people, of music tuned so that 528 Hz falls in its scale (A = 444 Hz). One study in rats, one in cell cultures. None tested a 528 Hz tone in people.

K. Akimoto et al., Health 10 (2018) 1159–1170. T. Babayi Daylari et al., Genes & Genomics 41 (2019) 201. T. Babayi and G. H. Riazi (2017).

Cited for what testing found, not as support for the claim.

R. W. Moran and P. Gibbons, Journal of Manipulative and Physiological Therapeutics 24 (2001) 183. A. Guillaud et al., PLoS ONE 11 (2016) e0167823.

Cited for the range in which suppression was strongest: 446 to 477 nm.

G. C. Brainard et al., Journal of Neuroscience 21 (2001) 6405.

The book that introduced the six original Solfeggio tones. Cited as the origin of the claim, not as evidence for it.

Leonard G. Horowitz and Joseph Puleo, Healing Codes for the Biological Apocalypse (Tetrahedron, 1999).

An account of where the bowls come from and when they were first described as singing bowls.

Grimes, Tricycle: The Buddhist Review.

No originating publication was found for 174, 285 and 963 Hz.

What manufacturers say about their own instruments. No independent source was found.

The tables that the tuning pages on this site reproduce.

Hans Cousto, Tuning Data — Earth Moon Planets Sun. Planetware.

The maker’s own figures for each gong’s fundamental note.

Paiste AG, Planet Gongs: product specifications.

A randomized trial in 120 children. The record says it is completed. No results were posted when this site checked, on September 27, 2026.

ClinicalTrials.gov, NCT07013669.

An explanation of dielectric heating, and of why the oven is not tuned to a resonance of water.

C. Baird, West Texas A&M University, “Science Questions with Surprising Answers”.

Orbital periods, lunar cycles and the solar cycle.

NASA Planetary Fact Sheets. NASA Eclipse Web Site (lunar cycles, Saros). NOAA Space Weather Prediction Center (solar cycle).

The reference range for a resting adult. A published range, not a journal paper.

American Heart Association.

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