In the 2+ decades I've been playing guitar, I've always known that A was tuned to 440 Hertz. I didn't always know what that meant, exactly, but I understood it to be one of those truths you hold self-evident if you want to stay in tune.
Apparently, however, the standard tuning of an "A" pitch was not always equivalent to 440 Hertz; in fact, some would argue that such a claim is literally an abomination, because Nazis.
We'll get to that; but first, a little history from Global News CA:
As early as 1885, the Music Commission of the Italian Government declared that all instruments and orchestras should use a tuning fork that vibrated at 440 Hz, which was different from the original standard of 435 Hz and the competing 432 Hz used in France.
In 1917, the American Federation of Musicians endorsed the Italians, followed by a further push for 440 Hz in the 1940s.
In 1953, a worldwide agreement was signed. Signatories declared that middle "A" on the piano be forevermore tuned to exactly 440 Hz. This frequency became the standard ISO-16 reference for tuning all musical instruments based on the chromatic scale, the one most often used for music in the West. All the other notes are tuned in standard mathematical ratios leading to and from 440 Hz.
But some people actually believe that middle "A" should be 432 Hertz, which is somehow more "perfect" and thus harmoniously soothing than 440 Hertz. Wikipedia actually sums this up with hilarious perfection:
Since 256 is a power of 2, only octaves (factor 2:1) and, in just tuning, higher-pitched perfect fifths (factor 3:2) of the scientific pitch standard will have a frequency of a convenient integer value. With a Verdi pitch standard of A4 = 432 Hz = 24 × 33, in just tuning all octaves (factor 2), perfect fourths (factor 4:3) and fifths (factor 3:2) will have pitch frequencies of integer numbers, but not the major thirds (factor 5:4) nor major sixths (factor 5:3) which have a prime factor 5 in their ratios. However scientific tuning implies an equal temperament tuning where the frequency ratio between each half tone in the scale is the same, being the 12th root of 2 (a factor of 1.059463), which is not a rational number: therefore in scientific pitch only the octaves of C have a frequency of a whole number in hertz.
Got all that? Don't worry; it doesn't really matter. What matters is that some dudes in the 18th century preferred 432 Hz over 440 Hz, and it's mostly arbitrary, but 440 ultimately won out when industrialization meant humans had to start standardizing arbitrary things. If you want to hear the subtle difference between the frequencies yourself, here it is.
But here's where it gets interesting, as Dr. Leonard Horowitz once explained:
This history concerns A=440Hz "standard tuning," and the Rockefeller Foundation's military commercialization of music. The monopolization of the music industry features this imposed frequency that is "herding" populations into greater aggression, psychosocial agitation, and emotional distress predisposing people to physical illnesses and financial impositions profiting the agents, agencies, and companies engaged in the monopoly.
Between World Wars I and II, accelerating during the 1930s, scientific studies in musical frequencies best suited for war-making were funded by the Rothschild-Rockefeller alliance, represented by the Rockefeller Foundation and U.S. Navy.
A major objective of this war, and profitable population control, research was to determine the musical factors capable of producing psychopathology, emotional distress, and "mass hysteria."
Dr. Horowitz links this to Theodor Adorno, a leading figure in the Frankfurt School that "invented" "Cultural Marxism." This, in turn, leads to the CIA, which leads to GE, which somehow (it's not clear) leads directly to Joseph Goebbels:
The A=440Hz frequency was instituted at the precise time WWII preparations were being finalized by the petrochemical-pharmaceutical war financiers. Hitler's Germany invaded Poland officially starting WWII on Sept 1, 1939. Only three months earlier, following widespread rejection of the A=440Hz frequency vibration by musicians worldwide, Nazi propaganda minister Joseph Goebbels argued on behalf of this, apparently very important, intrusion into musical artistry, effectively persuading Hitler's supposed enemies in Britain to adopt this allegedly superior standard tuning for the "Master Race."
At this point it should be noted that Dr. Horowitz is a retired dentist who is utterly full of shit when it comes to the acoustical physics of biomusicology or whatever the fuck he's on about. But that hasn't stopped YouTube (and scientific journals!) from erupting with pseudoscience about the "meditative" qualities of 432 Hertz—which, of course, relates back to Horowitz's theory that 440 Hertz is a weapon of Nazi aggression.
Like most batshit conspiracy theories, there is some kernel of truth here—that there has been an historical debate between these frequencies for middle "A," and that 440 Hertz won out largely because of Western industrialization, which coincided with some World Wars.
But it's kind of incredible—and incredibly frustrating—to think that there are people out there who can pick on 8 Hertz of a frequency and find a way to turn it into a Nazi conspiracy theory.
Are We All Mistuning Our Instruments, and Can We Blame the Nazis? [Ted Gioia / The Daily Beast]
The great 440 Hz conspiracy, and why all of our music is wrong [Alan Cross / Global News]
Image: Public Domain via NeedPix