according to my calculations, if you tuned to e-flat on the guitar, in standard tuning you would have an a-flat as your '2nd' string.

but if you are yet assuming 'a' to equal 440, the a-flat string in an e-flat tuning would be roughly 421.6666 cycles

in either event tuning to e-flat doesn't appear to result in, '432 tuning'...

in other words, 432 is not a half-step below 440... rather, it is a some kind of 'semi-tone in distance'...

here is another thing... if one is using a 12-tone scale, why not have notes 'a' through 'l' with no sharps or flats?

a staff with perhaps 6 lines?

as it is, the sharp-flat system with the 5-line/4-space staff is a fascinating invention... apparently a way of at once musical shorthand and 'visual compression' for those who care to learn it ....

but a question persists: does it represent the 'natural universe' or is it rather a 'cultural convention?'

another key to all of this... it is the tri-tone... that frequency directly between any given 2 octave notes... for example the d# or e-flat between 'a 440' and 'a 880'...

it used to be 'illegal' (during the inquisition or somesuch) because it was thought to be 'the devil's note'...

as it turns out, the 'doubly-diminished 7' chord gives us a 'haunted house' sound... for instance, the simple g# b d f combination found in 'a, harmonic minor'...

and here we haven't even delved much into semi-tones... scales with more than 12 tones.... as sometimes found in both the near and far east...

did you know that steve vai built one guitar which was divided into quarter tones?... whereas the standard, 'western' guitar is divided into half-tones (or half-steps)... his special guitar broke it down into quarters... 24-frets per octave... that must have been a long neck on that bad boy!

the standard, 'grand piano' is an insrument of astounding depth and beauty... yet it is rigid in its 12-tone structure...

the standard electric guitar, with its 12-fret setup, appears at first glance to be regimented like the piano... yet the use of 'string bends,' 'whammy bars,' and 'false harmonics' allow the guitarist access to a dizzying array of available tones...

of course 'modern,' 'keyboardists' may have the most flexibility of all, what with all of the advances in synthesizer, sequencer, and sampler technology and whatnot...

it is interesting in any event; the op's original premise that the 440 tuning is hard on the human voice, and that basing 'everything' musical off of 432 rather than 440 would put western music as a whole more 'into sync' with the universe at large...

interestingly, if we take a=440 and of course a=220, then the intervals break down into 18.33333 cycles apart... 220 (the distance between the 2 'a' notes) divided by 12 is 18.33333

it is fascinating to note that if we were to employ a=432 and by definition, a=216... that the intervals would be a round number, 18...

216/12 = 18

and 432/12 = (36 of course)

fascinating...

perhaps there is some 'musical conspiracy' to be uncovered, or is it all simple an 'accident' of hystory?

finally, here is another thing to consider, whether in a=440 or a=432... the 7-note scales derived from the '12-tone palette' of notes...

professor bainbridge has devised 3 new types of minor:

"dynamic minor" ... example based on the key of 'a-flat':

a-flat b c d e f g

this one could be explained in terms of western theory as 'a, harmonic minor with the 'tonic' ('a') removed and the g retained, and the g# renamed to a-flat'... this key wishes to resolve to either the 'a minor triad' or - perhaps secondarily - to the 'f minor triad'... interestingly, the 'a minor triad' doesn't even exist within the structure of the key....

let's now look at professor bainbridge's, "contratonic" minor:
here in the key of 'e minor'

e f## g## a# b# c# d#

this one is amazing... i have not yet found any way to describe it in classical theoretical terms...


let's have a look at 'kinetic minor,' also discovered/invented by professor bainbridge:

in the key of 'd minor'

d e# f# g# a b c

interestingly, this one is in 'd minor' but it looks like 'a, melodic minor with an e# thrown in'... or 'let's play in a, melodic minor but with an f (e#) note instead of an e note'

as an offshoot of these keys by professor bainbridge, i have 'thrown together' 'astral minor' which in the key of 'a minor' is:

a b c d e f gb

described as, 'let's take 'a minor' with an f and an f# but leave out g and g#'

or 'unorthodox minor' which is a 9-note scale... in 'a minor' it is:

a b c d e f f# g g#

now it could be said that this is simply 'melodic minor without the '6th and 7th sharped when going up, normal when going down' rule'...

when notating this one in 9-note fashion, the notes are:

a b c d e f g-flat h (g) i (g#)

interestingly, in all of these new minor keys ... whether bainbridge's discoveries or my own meanderings... if you 'build out' the triads... it's some crazy stuff...

for example, in 'e contratonic minor' you have:
e g## b# (could be stated as 'a minor')
f## a# c# ('g diminished')
g## b# d# ('a diminished')
a# c# e ('a# diminished')
b# d# f## ('c minor')
c# e g## ('A Major')
d# f## a# ('D# Major')

it's phreaking brilliant!

bainbridge's are perhaps more interesting in that they all eschew 'consecutive half-steps'

so the question there is, why were these keys - particularly professor bainbridge's - seemingly ignored in western musical theory?

in any event, going to a=432 seems like it would be a good move...