What is 432Hz?

A plain-language explainer · Updated October 2026

“432Hz” is one of the most common labels on relaxation and meditation music. It sounds technical, but the idea is simple: it describes how the music is tuned. Here’s what it means, where it came from, and what is and isn’t known about it.

Hertz and tuning, in one minute

A hertz (Hz) is one cycle per second. A sound wave that vibrates 440 times a second has a frequency of 440 Hz, and we hear it as a particular pitch. To play together, musicians agree on a reference pitch: one note that everything else is tuned around. By convention that note is the A above middle C.

The international standard, ISO 16, sets that A at 440 Hz (ISO 16:1975). “432Hz music” means music where that same A is set to 432 Hz instead, and every other note moves down with it. The difference is about 32 cents, roughly a third of a semitone. That’s small enough that most people wouldn’t notice it in a single song, though some listeners describe 432Hz-tuned music as slightly darker or warmer.

You’ll also see “432Hz” used more loosely, for a single sustained tone at 432 Hz or for music built around that tone. Either way, the number refers to the pitch, not to anything else about the sound.

A short history of concert pitch

For most of musical history there was no single standard. Pitch varied from city to city and from instrument to instrument. In the early 1700s the French physicist Joseph Sauveur measured the A of the instruments around him at roughly 405–421 Hz. In 1713 he proposed a system based on middle C at 256 Hz, later called “scientific” or “philosophical” pitch, which puts A at about 430.5 Hz (Scientific pitch).

In the 19th century, orchestras were creeping sharper, and several standards competed:

1834: Johann Heinrich Scheibler recommended A440, and a meeting of German scientists in Stuttgart approved it. That’s why A440 is sometimes called “Stuttgart pitch” (A440).
1860s: France set a standard of 435 Hz, which many countries adopted. Austria’s 1885 recommendation was also 435 Hz (A440).
1870s–80s: The composer Giuseppe Verdi insisted on 435 Hz for his Requiem and later suggested that 432 Hz would be slightly better for orchestras. This is the origin of the name “Verdi tuning” (Scientific pitch).
1936–1939: The American Standards Association recommended A440 in 1936. In 1939, delegates from several European countries met at the BBC’s Broadcasting House in London and agreed on A440 (A440).
1955 and 1975: The International Organization for Standardization adopted A440 as a recommendation in 1955 and formalised it as ISO 16 in 1975. ISO last reviewed and confirmed the standard in 2022 (ISO 16:1975).

Even today the standard isn’t universal. Orchestras in continental Europe commonly tune somewhere between 440 and 444 Hz, and period-instrument ensembles often use a “baroque pitch” of 415 Hz (A440).

How 432Hz became popular

Interest in 432 Hz grew in the late 20th century. In 1988 the Schiller Institute began campaigning for “Verdi tuning” at A432 as a classical concert standard. Historians and musicians disputed many of the claims made alongside that campaign (Scientific pitch). Online, 432Hz has since become a popular genre label for ambient, meditation and sleep music, and many tracks are retuned from 440 to 432 for that audience.

What does the research say?

Very little research has looked at 432Hz directly. The most-cited study is a 2019 pilot by Calamassi and Pomponi. Thirty-three volunteers listened to the same film soundtracks tuned to 440 Hz on one day and 432 Hz on another. The authors reported a slightly lower average heart rate after the 432 Hz sessions, and participants said they were a little more satisfied. Other changes weren’t statistically significant. The authors themselves called for larger randomised trials (Calamassi & Pomponi, 2019). A single small pilot study can’t settle the question. Summaries of the topic note that there is no scientific evidence that 432Hz music has healing benefits (Scientific pitch).

Why Whole Hum uses it

We use 432Hz tuning as a sound and style choice. It’s the tuning many listeners look for, and its slightly lower, softer centre suits slow, spacious music. We don’t claim it does anything special to your body. If you’re curious, try listening to the same piece at both tunings and see which you prefer. It’s a matter of taste, and there’s no wrong answer.

Not medical advice. This article is for general information. Whole Hum sessions are for relaxation and enjoyment and aren’t a treatment for any condition.

Sources

International Organization for Standardization. ISO 16:1975 Acoustics: Standard tuning frequency (Standard musical pitch).
Wikipedia. A440 (pitch standard).
Wikipedia. Scientific pitch.
Calamassi D, Pomponi GP (2019). Music tuned to 440 Hz versus 432 Hz and the health effects: a double-blind cross-over pilot study. Explore 15(4):283–290.