>>16599724OP, pay attention. This is real simple.
Root key 432Hz is only half the equation. You also need Pythagorean temperament.
>Note that most modern instruments (guitar, piano, brass) are essentially hard-coded in Equal temperament. Classical string instruments (violin, viola, cello, etc) are not, because they have no frets.>>16599728Yes, let's. This is how you derive all the frequencies of Pythagorean A432. Literally get out a sheet of paper and do this very very simple math and you will 100% understand.
Start with C = 1Hz. Double it to get its octave. Keep doubling and you get all the Cs. Multiply each of those by 3/2 and you get its perfect fifth, G. (See picrel chart. We're just walking around the Circle of Fifths, deriving all the frequencies.)
Multiply that G by 3/2 and you get its perfect fifth, D
Aaaaand multiply D by 3/2 and you get its perfect fifth, A
And THAT is where we get A=432