432 Hz and 440 Hz
432 Hz or 440 Hz: what is concert pitch?
440 Hz is a standard: agreed in 1939, adopted as an ISO recommendation in 1955 and fixed as ISO 16 since 1975 — not a natural constant. 432 Hz is a different, older tuning, attributed among others to Giuseppe Verdi. Neither one is "better" or "healthier" — just tuned differently. Radio 432 makes the difference audible and lets you choose.
440 Hz: the standard
For orchestras worldwide to sound together, a shared reference pitch is needed. In May 1939, representatives from France, Germany, the Netherlands, Italy, and England met at BBC Broadcasting House in London and agreed on 440 Hz for concert pitch A. In 1955, the International Organization for Standardization (ISO) adopted the result as recommendation R 16; in 1975 this became the ISO 16 standard still valid today. So 440 Hz is not a natural constant — it's a standard that was agreed internationally.
432 Hz: a different, older tuning
432 Hz can be derived mathematically: if you set the note C to 256 Hz (a power of two, "scientific pitch", described in 1713 by Joseph Sauveur) and calculate with the Pythagorean major sixth (27:16), the result for A is exactly 432 Hz. The tuning is attributed, among others, to Giuseppe Verdi: in 1859 France legally mandated a "diapason normal" of 435 Hz to slow the sharply rising orchestral pitch of the time and spare singers' voices. Verdi kept to those 435 Hz for his 1874 Requiem, but later expressed a slight preference for 432 Hz in a letter — hence the name "Verdi tuning". That isn't proof that 432 Hz historically stems from this derivation; the calculation only shows that the two numbers line up.
What's measurable, what's attribution
What's measurable is the pitch itself: the gap of around 32 Cents measure small pitch differences: 100 cents make a semitone, 1 cent is barely audible. More about cents → , the ratio 54/55. Stories like "432 Hz as the frequency of the universe" or as a measurement of the Great Pyramid of Giza can be found on the internet, but not in verifiable sources — the same goes for claims that 432 Hz is more calming or healthier than 440 Hz: there's no scientific evidence for that. What remains is your own listening impression. Radio 432 doesn't claim any of this — it just lets you compare for yourself: switch, listen, decide.
What a cent is
A Cents measure small pitch differences: 100 cents make a semitone, 1 cent is barely audible. More about cents → is the unit musicians and acousticians use to express pitch differences — not in hertz, because hertz gaps sound different sizes depending on the register. By definition, 100 Cents measure small pitch differences: 100 cents make a semitone, 1 cent is barely audible. More about cents → make a semitone and 1200 Cents measure small pitch differences: 100 cents make a semitone, 1 cent is barely audible. More about cents → an octave; the scale is logarithmic, the way hearing itself works. 1 Cents measure small pitch differences: 100 cents make a semitone, 1 cent is barely audible. More about cents → on its own is barely audible. The gap between 440 Hz and 432 Hz is about 32 Cents measure small pitch differences: 100 cents make a semitone, 1 cent is barely audible. More about cents → — just under a third of a semitone.
You have the vote
Radio 432 listens continuously and measures how the music you listen to is tuned. It lets you switch between the original and 432 Hz. Neither tuning is better — it's just a choice.
Sources
- Concert pitch (Kammerton) — Wikipedia: on the 1939 London conference and standardization as ISO 16.
- ISO 16:1975 — Acoustics: Standard tuning frequency (Standard musical pitch). International Organization for Standardization.
- Concert pitch — Wikipedia: on the French "diapason normal" of 1859 and Giuseppe Verdi's 1874 Requiem.
Last checked: October 4, 2026