Some good news for the clients whose pianos can’t be tuned to concert pitch (usually due to age and their poor condition) and had to be tuned thirty cents flat; I have left your piano with special healing powers! If you ask Winfried Otto Schumann that is who believed music played at A432 was more in tune with nature (see this article at attunedvibrations).
The gist of the article is that the fundamental resonant frequency of the universe is 8hz, a pitch inaudible to the human ear but is the frequency of much electromagnetic activity on our planet. If a piano’s bass section had more octaves and I were to tune the whole piano starting from an extremely low note which resonated at 8hz, we’d find the A above middle C to be 432hz rather than 440hz (440hz being the agreed upon standard since the early twentieth century), which interacts more harmoniously with the natural world, creating soothing effect on the human mind and body.
Historically the agreed pitch standard of Orchestras has tended to be lower than A440, with the tendency being for the pitch standard to rise over time with efforts to produce brighter and more brilliant sounding music. It was only in the early twentieth century that musicologists decided upon the A440, much to the dismay of singers who found this higher pitch standard vocally straining and other critics.
Perhaps the opponents of A440 were right all along? Speaking from personal experience I’ve found many pianos I’ve tuned sound better at A432 or A435 – although these tend to be pianos from a different era. Modern uprights clearly lose character when they’re too flat of A440.