432 Hz

One pitch and nothing else

There is nothing under the tone and nothing above it: no bass, no shimmer, no texture, no events. Both ears get the same signal, so speakers and headphones deliver the same sound and there is no reason to reach for headphones. A bare tone is either exactly what you wanted or far too plain to sit with, and twenty minutes will not change your mind about which.

Where the 432 argument comes from

Concert pitch used to be a local decision. Surviving tuning forks and organ pipes from the eighteenth and nineteenth centuries put A anywhere from the high 300s to the high 450s, which is why old wind instruments often will not play in tune with a modern orchestra. Verdi argued for A at 432 on practical grounds for singers, and an Italian government decree adopted it in 1884. An international conference recommended 440 in 1939, and ISO 16 fixed it in 1975. Both numbers are committee decisions.

The rest of the story does not hold up. Nothing shows that 440 was imposed as propaganda, no mechanism connects 432 to the Schumann resonance or to any measurement of the Earth, and no systematic review or clinical guideline stands behind the effects people attribute to the number. What is left is a pitch slightly below the modern standard. Some listeners prefer how that sounds, which is reason enough to play it.

A single tone is not retuned music

Most people searching for 432 Hz want music transposed so that A lands there instead of on 440: whole recordings shifted down by that third of a semitone. This file is not that. It is one pitch with nothing else in it, a drone to work or sit against rather than something to follow.

Compare it by ear against the brighter 396 Hz tone or the much deeper 174 Hz tone, and see every browser player on the sound library index. A bare pitch is easier to sit with when something broadband runs underneath it, so open the 432 Hz and brown noise blend in the free sound mixer and set each layer where you want it.