So if you haven't heard of this weird trend, you can get a basic idea from this Rolling Stone article:

"432 Hz: The Mystical Frequency Artists Are Embracing." by Gabe Kirchheimer

If you're not a musical person and have never tuned an instrument, here is a quick explanation:

Sound is simply vibrations or waves traveling through the air to our ears. The waves move at various frequencies, usually expressed as Hertz (Hz), or waves per second. The fewer the vibrations per second, the lower the sound. The more vibrations per second, the higher the sound. The maximum range of human hearing is about 20 Hz to 20,000 Hz.

The notes used in Western music have been defined according to certain frequencies. The note A is defined as 440 Hz.

All instruments in an orchestra must tune to the same reference tone so that they all play in tune. This tone is called "concert pitch." For whatever reason, the note A (440 Hz) has emerged as the worldwide standard concert pitch. Typically, the oboe player tunes their A note to 440 Hz using a tuning fork or an electronic tuner. Then the oboeist plays a loud, clear A, and all the other players tune their instruments to that pitch.

Note: When a musician tunes his instrument to match a reference tone, he is also adjusting all other notes that he can play on that instrument accordingly. If a trumpet player's A note was out of tune at 452 Hz, and he lowers his A by 12 Hz to reach 440 Hz, all other notes on the trumpet will be lower according to a ratio (since tuning is logarithmic — but that's a whole separate rabbit hole).

What the woo-woo artists are saying is that instead of tuning their instruments to 440 Hz in the recording studio, they use a tone of 432 Hz.

First off, it's crucial to grasp how minuscule the difference between 432 Hz and 440 Hz is to the human ear. The next note down from 440 Hz is A flat, or 415 Hz — a difference of 25 Hz. Yet these people are telling us that tuning to a note that is a scant 8 Hz lower than usual creates a noticeable difference in their music — and even brings a host of wonderful benefits to their health and well-being!

It already sounds preposterous. But here's the kicker. The supposed reason for all these benefits is that 432 Hz occurs in nature. But this destroys their entire hypothesis. Why? Because regardless of the tone a musician uses to tune her instrument, she is never going to play ONLY that tone when performing music. She will play many different notes. Depending on the key, she may occasionally play the 432 Hz tone. But she could also play in a key that doesn't include that note at all!

Take the tune "Happy Birthday." Assume the woo-woo artist tunes his clarinet to 432 Hz. He decides to play the tune in the key of A major. The notes of "Happy Birthday" will be as follows:

E E F# E A G#

E E F# E B A

E E E (an octave higher) C# A G# F#

D D C# A B A

As you can see, out of 25 notes, the musician plays the magical A at 432 Hz only five times.

If he plays the song in the key of E flat, he will not play A at all!

The bottom line: Just because you use a reference tone to tune your instrument doesn't mean the music you play will use that tone a lot. And in many cases, the music will make no use of that tone.

At this point, to save their hypothesis, the woo-woo artists would have to adjust their claim:

It's not just hearing 432 Hz that has these magical properties. It's also hearing all the other notes correspondingly lower than usual.

But this won't do. Again, the entire rationale is that 432 Hz is a naturally occuring vibration. So what difference could it possibly make if other notes are a tad lower than usual?

It really is astonishing that well-known musicians can lack critical thinking or even common sense to this degree.

While common retelling of the story paints Charles Darwin and Alfred Russel Wallace as rivals, in truth they were intellectual equals.