432 Hz Explained: Tuning, Myths and What Listening Tests Show

The note A has never had one fixed pitch. A tuning fork linked to Handel sounds at about 422.5 Hz. One linked to Beethoven sounds at about 455 Hz. Somewhere between the two sits 432 Hz, a number that has since gathered a surprising amount of lore.

The short version: 432 Hz is a perfectly good pitch, and the special claims around it are not backed by solid evidence. The longer version starts with what the number actually means.

What the number means

Hertz (Hz) counts how many times a sound wave repeats each second. A higher number is a higher pitch. In music, 432 Hz usually refers to a tuning: the note A above middle C is set to 432 Hz instead of the modern standard of 440 Hz. Everything else in the music shifts down with it.

The difference is small. By our own arithmetic, 432 Hz sits about 32 cents below 440 Hz, which is roughly a third of a semitone (the step between two neighboring piano keys). The same song tuned both ways would sound very similar, with the 432 Hz version very slightly lower.

432 Hz can also mean a plain tone, a single steady pitch at that frequency, with no music at all. The tuning and the tone are different things, and studies tend to test the tuning.

How 440 Hz became the standard

Those two forks are snapshots of a moving target. In the 1800s, pitch crept upward in many places. France set A at 435 Hz in 1859, and other countries followed.

A pitch of 440 Hz was recommended by an international conference in London in 1939 and adopted by the International Organization for Standardization in 1955 (and as ISO 16 in 1975). Even today it is not universal. Baroque ensembles often tune lower, and some orchestras tune a little higher, up to about 443 Hz.

So 440 Hz is a convention that people agreed on. It is not a law of nature, and neither is 432 Hz.

Where the claims come from

Two threads run through the story.

The first is history. The composer Verdi is said to have proposed a slightly lower standard than the French one, and a group called the Schiller Institute later promoted 432 Hz as “Verdi tuning.” That movement did not catch on in concert halls. Since the early 2000s, many websites have promoted 432 Hz with unsupported claims of special effects.

The second is numbers. One argument links 432 Hz to a middle C of 256 Hz, which is a power of two and so sits neatly on octaves. The authors of a 2025 trial note that this idea rests on “historical and philosophical interpretations and not on empirical data.” In other words, it is an appealing pattern, not a measurement of what a sound does to a listener. So when someone says 432 Hz is closer to nature, this is the argument behind it, and it is an argument rather than a measurement.

Can you hear the difference?

Maybe, if you listen side by side. A reference source on pitch discrimination says that below 500 Hz, listeners can tell two pure tones apart when they differ by about 3 Hz. The gap between 432 and 440 Hz is 8 Hz, more than that. Played back to back, many listeners can tell. Heard separately, it is much harder.

Real music is harder to judge than a lab tone. In the 2025 trial described below, the authors called a similar pitch gap hard for the average listener to notice, yet 65% of the patients said they noticed a difference.

What the listening tests found

A handful of small studies have compared 432 Hz with 440 Hz or a nearby tuning. All of them are pilot-sized, and their authors say so.

2019, Explore. Thirty-three adults without a long-term illness listened to 20 minutes of the same movie soundtracks, once at 440 Hz and once at 432 Hz, on different days. After 432 Hz, average heart rate was 4.79 beats per minute lower (p = 0.05, right at the usual cutoff). Changes in blood pressure and breathing rate were not statistically significant. Listeners also rated themselves more focused and satisfied. The authors asked for larger, randomized trials.
2020, Acta Biomedica. Twelve patients in one spinal unit listened to their favorite music in each tuning for 30 minutes a day. Self-rated stress fell, but not significantly, in both. A self-rated sleep score rose after 432 Hz (p = 0.02) and not after 440 Hz. The authors called for bigger samples.
2025, a BMC complementary medicine journal. Forty-three patients in a university hospital heard a 15-minute session on a body monochord, tuned to 432 Hz in one session and 443 Hz in another. Heart rate fell by a median of 3 beats per minute after 432 Hz and 1 after 443 Hz. Most other differences between the two tunings were not statistically significant. The authors note they can’t tell whether the result comes from 432 Hz itself or from lower pitches simply sounding more pleasant.

Taken together, these are a few small studies with modest and mixed results. Several rely on how people rate themselves, all are small, and in the 2025 trial the pitches were played by hand by one performer. They are interesting, not settled.

So is 432 Hz better than 440 Hz? Not on the evidence so far. A few small studies report minor differences in measures like heart rate, but their authors call for larger trials. Both are simply tunings.

Why we call it Traditional / Unproven

OscillaMind, which is coming to iOS and Android, will list 432 Hz in its Frequency Library with the label Traditional / Unproven. That label rates the evidence for what people link with the sound, not the sound itself. The idea comes from tradition and online claims, the studies are small, and when the evidence is unclear we use the lower label.

That doesn’t make 432 Hz a bad choice. If you like how it sounds, a plain 432 Hz tone or music tuned that way is a fine thing to listen to on a quiet evening. Keep the volume low, and think of it as a sound you enjoy, not as a method.

Sound is for listening and routines, not medical care. If you have a health concern, talk to a doctor.

Sources

Concert pitch, Wikipedia. https://en.wikipedia.org/wiki/Concert_pitch
A440 (pitch standard), Wikipedia. https://en.wikipedia.org/wiki/A440_(pitch_standard)
Just-noticeable difference, Wikipedia. https://en.wikipedia.org/wiki/Just-noticeable_difference
Calamassi and Pomponi (2019), music tuned to 440 Hz versus 432 Hz, double-blind cross-over pilot study, Explore. https://doi.org/10.1016/j.explore.2019.04.001
Calamassi, Lucicesare, Pomponi and Bambi (2020), music tuned to 432 Hz versus 440 Hz, double-blind cross-over pilot study, Acta Biomedica. https://mattioli1885journals.com/index.php/actabiomedica/article/view/10755
Hohneck et al. (2025), sound interventions tuned to 432 Hz or 443 Hz, randomized cross-over trial, BMC (Springer Nature) complementary medicine journal. https://pmc.ncbi.nlm.nih.gov/articles/PMC11755923/