Spiritual awakening frequency: 963 Hz and the Platonic year tone

Is there a frequency for spiritual awakening?

Not one that has been tested. No study has measured anything spiritual in people listening to 963 Hz, 172.06 Hz or the two together, and PubMed, the main index of medical research, lists no study of listening to either tone.

What exists is a pairing with a tradition behind each half. It comes from Spirituality, a video on Harmonance's YouTube channel that joins 963 Hz, the highest of the nine Solfeggio numbers, with 172.06 Hz, Hans Cousto's tone for the Platonic year. It is one of the channel's nine fusion videos, each named for a state such as Focus or Grounding, and the two tones sit side by side on Harmonance's spirituality page.

This guide takes the pairing apart. It shows why both numbers are given to the crown chakra, where each one comes from, what the ear does with the two together, measured from the site's own audio, and what research on sound and spiritual experience has found so far, which is about singing bowls rather than any single tone.

Why are both tones linked with the crown chakra?

Because two different traditions each gave their highest number to the highest chakra. In yoga traditions the crown chakra, Sahasrara, is the seventh of the primary chakras, and its texts describe it in pictures, not pitches: "a lotus flower with 1,000 petals of different colors", at the top of the head.

Hans Cousto, who calculated the tones of the cosmic octave, gave his slowest cycle to that centre. His text on the Platonic year tone, from Die Töne der Kosmischen Oktave, lists "Chakra: Sahasrara - Scheitelchakra" beside 172.06 Hz and says this of music tuned to it:

Eine Meditationsmusik, die auf diesen Ton gestimmt ist, kann sehr förderlich sein auf dem spirituellen Pfad

In English: meditation music tuned to this tone can be very helpful on the spiritual path. The same text calls the tone the gate to the spiritual heaven. That is the closest any source comes to naming a spiritual awakening frequency, and it is a description from a tradition, not a measurement.

963 Hz reached the crown by another road. Modern charts pair the nine Solfeggio numbers with the chakras, and the highest number sits with the highest centre. As the guide to chakras and frequencies explains, those pairings are a recent addition to a much older tradition. So the Spirituality pairing joins two numbers that arrived at the same label separately.

Where does 963 Hz come from?

963 Hz comes from the modern Solfeggio set, and it joined the set after the first six numbers had been published. A 1999 book, Healing Codes for the Biological Apocalypse, drew six numbers from verse numbers in the Bible's Book of Numbers, and its publisher's press release announced them:

the codes revealed a series of six electromagnetic sound frequencies that correspond to the six missing tones of the ancient Solfeggio scale

The six run from 396 to 852 Hz, and 963 is not among them. Within two years others had gone further: a tuning fork maker's page, as the Internet Archive saved it in 2012, asks "Why 6 forks when others have gone to 9?" and dates its own question to November 2000. All nine appear together in a US trademark application filed in February 2007, in the order "396, 417, 528, 639, 741, 852, 963, 174, and 285".

That order shows the arithmetic. Carry the count one step past 852 and each digit rises by one: 8 becomes 9, 5 becomes 6 and 2 becomes 3, which gives 963. The 963 Hz guide follows the number's whole story, and the guide to the Solfeggio frequencies tells the story of the set, tone by tone.

Where does 172.06 Hz come from?

172.06 Hz comes from the slowest motion the Earth makes. Besides spinning once a day and circling the Sun once a year, the Earth's axis turns slowly against the stars, like a spinning top. NASA puts the cause in the Sun's and Moon's pull on the Earth's equatorial bulge and gives the length: "The cycle of axial precession spans about 25,771.5 years."

Cousto's tuning tables take a rounder figure for one full turn, which he calls the Platonic year: "The point of intersection, also called the vernal equinox, moves once through the ecliptic (zodiac) in 25 920 years." Counted as one slow cycle, that turn is about 0.0000000000012 Hz. Doubling a frequency raises it one octave, so Cousto doubles it until it can be heard.

The arithmetic is short enough to redo. A year of 365.242 days, the tropical year on NASA's Earth fact sheet, makes 25,920 years about 817.96 billion seconds. 2 to the power 47 is 140,737,488,355,328, and dividing it by that number of seconds gives 172.06 Hz. On NASA's 25,771.5 years the same 47 doublings give 173.05 Hz, about a tenth of a semitone higher.

On a piano tuned to A at 440 Hz, 172.06 Hz sits 25.5 cents below the F below middle C, at 174.61 Hz, where a cent is a hundredth of a semitone; Cousto's tables call it F. The 172.06 Hz guide follows the Platonic year in full, and the guide to planetary frequencies explains the method for every planet: the tone is arithmetic applied to a real cycle, not a sound that travels from space.

What happens when the two tones play together?

They stay well apart in the ear. The two tones and their faint harmonics never come close enough to beat or roughen each other, and Harmonance measured exactly how far apart they sit.

The inner ear sorts sound by pitch along a coiled membrane, and each place along it acts like a filter a few semitones wide. In 1965 Reinier Plomp and Willem Levelt played pairs of pure tones to listeners and found where roughness comes from:

These intervals are evaluated as consonant for frequency differences exceeding critical bandwidth, whereas the most dissonant intervals correspond with frequency differences of about a quarter of this bandwidth.

The width of those filters is measured in Cams, after the formulas of Glasberg and Moore: on that scale every filter is one Cam wide, and each Cam is about 0.89 mm along the membrane. Every line the two Harmonance pages play is placed on that scale below, measured from the pages' own audio files played together.

The numbers behind the chart

Line	Level	Place in the ear
172.06 Hz, the Platonic year tone	loudest	5.21 Cams
344.12 Hz, its 2nd harmonic	23.1 dB down	8.53 Cams
516.18 Hz, its 3rd harmonic	34 dB down	10.97 Cams
963 Hz, the Solfeggio tone	loudest	15.34 Cams
1,926 Hz, 963 Hz's 2nd harmonic	23.1 dB down	20.84 Cams
2,889 Hz, 963 Hz's 3rd harmonic	34 dB down	24.27 Cams

Download the measurements (CSV)

The two tones are 10.13 Cams apart, about ten ear filters, so by Plomp and Levelt's finding they sound consonant. Each page's tone carries two faint harmonics, at twice and three times its pitch, 23.1 dB and 34 dB below it. The closest any line of one tone comes to the other is the Platonic year tone's third harmonic, 516.18 Hz, which still sits 4.37 Cams below 963 Hz.

So nothing in the pair beats. On the roughness measure Harmonance uses for its own sound, the pair scores 0.11% of the roughest possible pair of equal tones near 963 Hz, and the strongest stray line in the mix, at 160.43 Hz, is 53.5 dB below the tones.

As an interval, 963 Hz is 5.597 times 172.06 Hz, or 2,981.5 cents: two octaves and a tritone, the interval of six semitones, played 18.5 cents narrow. It sits within about one cent of the whole-number ratio 28 to 5. On the piano that is close to an F and the B two octaves and a tritone above it, with 963 Hz sitting 44 cents below the B at 987.77 Hz.

The two do not sound equally loud at the same level. The ear grows more sensitive as pitch rises towards a few thousand hertz, so at the pages' shared level the Platonic year tone reads 50.4 phon and 963 Hz 64 phon in the equal-loudness model (ISO 226) that Harmonance uses for its own sound. For the two to sound even, the low tone would need about 10.8 dB more, so the gentler way to balance them is to turn 963 Hz down rather than the low tone up.

What does research say about sound and spiritual experience?

The closest research is about singing bowls, not tones. Four researchers, Goldsby, Goldsby, McWalters and Mills, published an observational study in 2017 in the Journal of Evidence-Based Complementary and Alternative Medicine, Effects of Singing Bowl Sound Meditation on Mood, Tension, and Well-being.

What they looked at. 62 adults, aged 21 to 77, lay down for a sound meditation of about 60 minutes, mostly Tibetan singing bowls, with crystal bowls, gongs and bells. Before and after, they filled in questionnaires on mood and tension, and a ten-item scale of spiritual well-being, the FACIT-Sp. The sessions ran at three centres, one of them a centre for spiritual living.

What they found. Afterwards people reported less tension and better mood, and the spiritual well-being scores rose:

Feeling of spiritual well-being significantly increased across all participants

What it does not show. The authors name the main limit themselves: "The most notable limitation was that this was a nonrandomized observational study without a control group." Without one, an hour of lying still in a calm room, with people who chose to come, could account for the change as well as the sound. It used live instruments with rich, shifting overtones, not a steady tone, and nobody has tested 963 Hz or 172.06 Hz this way.

Why it matters for listening. If you come to sound for a sense of meaning, the study points to the setting as much as the pitch: time set aside, lying still, sound with nothing to do. A pure tone is not a singing bowl, so it suggests a way to listen rather than a result for this pairing.

What little research there is on 963 Hz itself points away from calm. In an online test, 37 adults rated twelve pure tones, and in Kumar, Abhayapala and Samarasinghe's 2022 paper the ratings for calm fell as the pitch rose above 440 Hz: 963 Hz, the highest, sounded the least calm and the most angry of the twelve. That measured how the tones sounded, not how anyone felt, and the 963 Hz guide sets out its limits.

The guide to the science of sound healing sets out what research on sound and music has and has not found more widely. The US National Center for Complementary and Integrative Health sums the field up plainly:

However, because much of the research on music-based interventions is preliminary, few definite conclusions about their effects have been reached.

How do you listen to the Spirituality pairing?

Play each tone on its own page, or both together in Studio. On the 963 Hz page, press play to hear the tone; switch Strings on beside the player and strings tuned to its lower octaves play, with 963 Hz itself quietly underneath. The 172.06 Hz Platonic year page plays the other half. Nothing plays until you press play, and no account is needed.

To hear the two at once, open Harmonance Studio, which plays several tones together after a free sign-in. Set 963 Hz well below the Platonic year tone so the pair sounds about even, then sit or lie still for a few minutes and notice what you notice. If the high tone feels bright rather than settling, turn it down further or let the low tone play alone. No study sets a length or promises a result.

Keep the volume low. Loud listening is the one risk that is well established: the National Center for Complementary and Integrative Health notes that "listening to music at too high a volume can contribute to noise-induced hearing loss", and the World Health Organization's safe listening advice is that "you can safely listen to a sound level of 80dB for up to 40 hours a week", with your device's volume below 60% of maximum.

Both tones belong to larger sets. The Solfeggio collection plays 963 Hz with its eight companions, and the planetary collection plays the Platonic year beside the planets. The 963 Hz tone's nearest neighbour in the set, the 852 Hz page, is another quiet place to start.

For other ways in, the guide to sacred sound looks at chant, bells and singing bowls across traditions, the Studio guide shows how to build and save a mix, and the guide to the frequency for confidence takes apart another of the channel's pairings, Mars with 396 Hz.

Sources and limits

The story of each number rests on primary records: Cousto's own text and tables for the Platonic year tone, NASA's figures for the precession and the year, and the 1999 press release, a tuning fork maker's page and a 2007 trademark record for 963 Hz, read in their original or archived form. No study has tested either tone, or the pair, on anything spiritual. The research described is an observational study of singing bowl meditation with no comparison group, and an online rating test of how pure tones sound, and neither can say what this pairing does for anyone. The measurements of the two pages' sound are Harmonance's own, made from the site's audio files; the loudness comparison comes from a model of an average ear, not from listeners.

1. Hans Cousto, the Platonic year tone (in German): the crown chakra, the spiritual path and the 48th octave.
2. Hans Cousto, tuning data for the planets: the Platonic year of 25,920 years and its 47th octave, 172.06 Hz.
3. NASA Science, Milankovitch cycles and their role in Earth's climate: axial precession of about 25,771.5 years.
4. NASA, Earth fact sheet: the tropical year of 365.242 days.
5. Tetrahedron Publishing (1999), press release for Healing Codes for the Biological Apocalypse, Internet Archive copy: the six numbers the book announced.
6. SomaEnergetics, tuning fork product page, Internet Archive copy from 2012: sets of nine by November 2000.
7. US Patent and Trademark Office, application 77099679: all nine numbers, filed in February 2007.
8. Wikipedia, Sahasrara: the crown chakra in yoga traditions.
9. Plomp and Levelt (1965), Tonal consonance and critical bandwidth, Journal of the Acoustical Society of America: tones further apart than a critical band sound consonant.
10. Moore (2014), Development and current status of the Cambridge loudness models, Trends in Hearing: the ear's filter widths and the Cam scale.
11. Goldsby, Goldsby, McWalters and Mills (2017), Effects of Singing Bowl Sound Meditation on Mood, Tension, and Well-being, Journal of Evidence-Based Complementary and Alternative Medicine: 62 adults, one hour of singing bowls, no control group.
12. Kumar, Abhayapala and Samarasinghe (2022), frequency cues for human emotions, in Acoustics: 37 adults rating twelve pure tones.
13. National Center for Complementary and Integrative Health, Music and Health: What You Need To Know: the state of music research, and loud listening.
14. World Health Organization, Deafness and hearing loss: safe listening: safe levels and device volume.