Traditional / experimental practice
Solfeggio 639 Hz · Pure Tone
Three minutes of a 639 Hz pure tone. Beneath it, as in the Deep Field, a light, dark sound field built from the pitch's lower octave and fifth, with hall reverb; the tone itself stays plain. One of the main stops of the Solfeggio Path. The Solfeggio list is a modern spiritual interpretation; no scientific effect is claimed.
A traditional or spiritual practice, not a scientific claim.
Liner notes
- Body
- Pure tone · 639 Hz, Cluster drone · 79.88 Hz
- What do you hear?
- narrow · tonal · continuous
How is this sound made?
- Pure tone−29 dB
Pure tone · 639 Hz
- Cluster drone−33 dB
Cluster drone · root 79.88 Hz, 8 oscillators
- Reverb: hall, 35% mix
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Sound is generated on this device in real time; no files are downloaded from a server. There is a 8 s fade-in at the start and a 0 min fade-out at the end.
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What do we know, what don't we know?
T · Traditional/spiritual practiceLast reviewed 7 October 2026
No scientific claim is made; it is offered as a cultural or personal practice.
A traditional or spiritual practice, not a scientific claim.
The meanings of the Solfeggio frequencies
A modern spiritual interpretation; not a scientific claim.
Evidence level T: Traditional/spiritual practiceWhat do we know?
- Medieval solfège syllables (ut, re, mi…) are real music history.
- Today's list assigning Hz values to them is a modern spiritual interpretation, popularized by a non-peer-reviewed book published in 1999.Horowitz & Puleo 1999
- Lists vary between sources: some count six tones, others nine.
What don't we know?
- Evidence gapThe meanings given to the tones have not been scientifically tested, and different sources assign different meanings.
Studies
- Horowitz & Puleo 1999 · Book (not peer-reviewed)
A session's level is the weakest of its linked claims; it is never raised by a strong but unrelated claim.
Its neighbours on the map
The five sounds closest to this one by measured sound features.
- 1Solfeggio 528 Hz · Pure ToneBright · steady · no melodyBoth tone and drone · both steady · same goal: explore
- 2Solfeggio 396 Hz · Pure ToneBright · steady · no melodyBoth tone and drone · both steady · same goal: explore
- 3Solfeggio 417 Hz · Pure ToneBright · steady · no melodyBoth tone and drone · both steady · same goal: explore
- 4Solfeggio 741 Hz · Pure ToneBright · steady · no melodyBoth tone and drone · both steady · same goal: explore
- 5Solfeggio 852 Hz · Pure ToneBright · steady · no melodyBoth tone and drone · both steady · same goal: explore
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