396 Hz and 417 Hz sit next to each other in the Solfeggio list and are often compared. This page sets out what can actually be checked about the two: how far apart they are, what happens when they sound together, and where the numbers came from.
Listen first. Play 396 Hz and then 417 Hz in the Frequency Lab (free, no sign-up).
The two tones in numbers
| Item | 396 Hz | 417 Hz |
|---|---|---|
| Nearest piano note (A = 440 Hz) | 18 cents above G4 (392.00 Hz) | 7 cents above G♯4 (415.30 Hz) |
| One cycle | 2.525 ms | 2.398 ms |
| Wavelength in air (20 °C) | 0.866 m | 0.823 m |
| Our tracks using it (incl. Shorts) | 29 (15 long) | 19 (6 long) |
How far apart are they?
417 Hz is 89.5 cents above 396 Hz. A semitone is 100 cents, so the gap is a little less than one semitone: close to the step between two neighbouring piano keys, but not equal to it. Neither tone lands exactly on a piano key; 396 Hz sits a little above G4 and 417 Hz a little above G♯4.
What happens when they sound together
Played at the same time, two tones 21 Hz apart produce a fast beating, 21 times a second, which the ear hears as roughness rather than a slow wobble. Intervals this narrow are usually perceived as tense. If you want to layer them, separating them in time (one after the other) or by an octave gives a calmer result.
Where the numbers came from
396 and 417 are two of the six original numbers in the Solfeggio system popularised by Leonard Horowitz’s 1999 book, which describes them as derived by Joseph Puleo from verse numbers in the Book of Numbers. That account comes from the system’s proponents; no independent historical source has been found. The often-repeated link to medieval Gregorian chant does not hold: there was no hertz unit and no fixed pitch standard in the Middle Ages.
What research says
No peer-reviewed study testing the effects of 396 Hz or 417 Hz in people was found. The descriptive names attached to each tone come from the system and from listeners’ accounts, not from measurements.
Frequently asked questions
Which should I listen to?
There is no measured basis for choosing one over the other. Play both in the Lab and pick the pitch you find comfortable.
Are they a musical interval?
Almost a semitone (89 cents), slightly narrower than one.
Can I combine them?
Yes, but together they beat at 21 Hz and sound rough. In sequence they sit more comfortably.
This article does not guarantee any medical or health benefit and is not a substitute for professional medical care. If you have any health concerns, please consult a physician or other qualified professional.
