One of the most vocal proponents of 432 hz is Brian Collins, who runs the website omega432.com. In order to witness the power of 432 hz, Collins recommends purchasing several frequencies of tuning forks (including a 432), striking them, inserting them into separate glasses of water, and then tasting the water in each glass. This will obviously somehow exhibit the superiority of 432 hz.
Omega432.com also contains plenty of nonsensical babble such as
Saturn completes one precessional Great Year of 25,920 years every 864 of its “years,” a half cycle every 432 of its “years,” a quarter cycle every 216 of its “years,” and an eighth of a cycle every 108 of its “years.” This equals (108 x 30) 3240 years, or 45 degrees of precessional arc. We can continue counting in Saturn years down to 9, one 96th of the precessional year, or 3.75 degrees of arc and 270 earth years, which brings us to the alignment period of the galactic meridian and the zenith/nadir axis.
What all of this number manipulation fails to mention is that the measurement of hertz is a ratio of cycles per second, and that a second is “a measurement of time that correlates with the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.” Now if that isn't the shiniest, most spiritual thing you've ever heard, I don't know what is.
Another supporter of 432 hz tuning was Rudolph Steiner, the Austrian philosopher responsible for the teachings behind Waldorf Education. Steiner had many strange ideas about music, not the least of which was that the piano was the worst possible instrument for a child to learn. Additionally, he stated
[...] musical instruments are derived from the spiritual world; the piano, however, in which the tones are abstractly lined up next to each other, is created in the physical world by man. [...] A piano is like the Philistine who no longer contains within him the higher human being. The piano is the Philistine instrument. It is fortunate that there is such an instrument, or else the Philistine would have no music at all. [...] Naturally, the piano is a beneficial instrument [...] but it is the one instrument that actually, in a musical sense, must be overcome. Man must get away from the impressions of the piano if he wishes to experience the actual musical element.
Plenty of “experiments” proving the value of 432 hz can be found online. One particularly popular one shows sound frequencies being used to produce patterns in sand on a large steel plate. What they fail to point out is that the “scientist” sabotages the 440 hz measurement by loosening the wingnut in the center of the plate to produce a less pleasing result.