Aside from the conversation about A432, I enjoyed this a lot.

Specifically in reference to cymatics, I find it really interesting how so many notes in A440 seem to be scattered and intermittent whereas notes in A432 seem to generally be round continuous shapes.
Nate

Here's a little history - 

Johann Heinrich Scheibler recommended A440 as a standard in 1834 after inventing the "tonometer" to measure pitch, and it was approved by the German Natural History Society the same year. The American music industry reached an informal standard of 440 Hz in 1926, and some began using it in instrument manufacturing. In 1936 the American Standards Association recommended that the A above middle C be tuned to 440 Hz. This standard was taken up by the International Organization for Standardization in 1955 (reaffirmed by them in 1975) as ISO 16.

A432 is a really interesting topic. I grew up around hippies, who often believe that 432 "relates to the frequency the earth vibrates at" though how exactly depends on who you ask. I personally believe that how notes sound is a product of the cultural influences in the life of the listener. Something along the lines of the placebo effect. If you tell yourself a scale is better, that probably makes it sound better. It would be very cool though, if we learned that different tuning standards actually do affect our brain in specific ways People even closer to the fringes will tell you that A432 promotes peace and wellness, which is why, according to them, a440 was chosen. It all relates, they say, to suppression of art by the church back in the day when music was required to be plain and boring, and artistic expression was totally off the table.

It's a fun rabbit hole, but personally I'd like some real proof instead of all the "dude trust me's" you get when looking into the topic.

It's a funny coincidence you bring up the A440hz and the A432hz-- a friend mentioned this to me recently; he may use the A432hz in hospital/hospital-type settings.  

Hey Gregg, I think I'm going to resist going down this rabbit hole.  I doubt my ears are sensitive enough to hear the difference. 

However, a quick Google search reveals a handful of scientific articles on the supposed health benefits of listening to music tuned to 432 instead of 440 (lower heart rate, less anxiety, better sleep, etc.).  Interesting.

I'm interested in hearing from FOTMD Folk about cymatics and tuning their dulcimers A 432hz - instead of "concert pitch" A 440hz - do you hear a difference? I notice that my strings tuned down that little do seem more relaxed and seem to resonate longer. Recently totally at random I overheard two people agreeing that they had perfect pitch, but they weren't tuned to A 440 which sounded "sharp, strident, and sometimes painful" to them and they had discovered that they much preferred music and tuning their instruments to A 432hz. Cymatics shows sand on a plate and water respond to different notes by forming different geometric designs, check out some YouTube videos on the subject.