There are two reasons why there is interest on changing the tuning system of the piano.
1. the physics of sound, and
2. its effect on musicality.
For many contemporary musicians music has become merely a circus act because the true nature of music has been forgotten. It has become only a challenge in virtuosity, a spectacle, "man versus beast". Musicians have forgotten the purpose of music as
- a language to convey emotion
- to enable the mind to explore different dimensions of experience
- and to heal.
Healing requires gentle caressing, and harmony not of sound but of the vibrations within sound.
Sound is made of vibrations, regular vibrations per second. These vibrations are either exactly related and part of the total sound, or they are not together and do not relate to each other, producing beats between them.
This produces contrast as between
- solid versus liquid
- certain versus uncertain
- calm versus stressed
Modern piano tuning does not maximise the numbers of vibrations which coincide - which then contrast with those sets of vibrations which do not coincide.
The change to modern tuning was made between 1860 and 1920. At this time the current tuning was used increasingly, becoming universal. It is exact "equal temperament" where each semitone is an exact same distance apart.
1. Physics of sound.
A note which is an octave higher than another note is double the frequency of the lower note. Twice the number of vibrations per second. So "A" in the middle of the piano keyboard is 440 vibrations per second. The "A" above is 880 vibrations per second. The octave above that is 1760 vibrations per second, 1760 "Hz".
When playing the organ, the sound can be made more interesting using "stops" to sound all three pitches, 440, 880 and 1760 from the same note.
All sound is made of timbres in combination of these multiples of vibrations together.
You can hear this when you sing a note and open your mouth to allow the extra sounds to be heard. I demonstrate this on a video https://youtu.be/TF2Cj3ak-Kk.
When a string is struck, all these frequencies vibrate exactly together to give the tone of the string. These frequences form part of the tone of the instrument.
For example, let's tune a string to 100 vibrations per second - 100 "Hz". Giving good tone on the piano this string will produce vibrations at 100, 200, 300, 400, 500, 600, 700, 800 and more vibrations per second.
If we hold down a note at 100Hz in the bass whilst we strike the keys above, for 200, 400 and 800 (an octave above, two octaves, three octaves and four octaves) then these frequencies will excite and resonate the undamped bass string. The sound will continue to be heard in the bass string: even when the upper note stops sounding. This is demonstrated on https://www.youtube.com/watch?v=Pz0B0SwKpww
where you can hear this effect.
What is interesting is that when we play two notes together, such as 500 and 600 vibrations per second, then these vibrations will coincide 100 times per second. So the bass note is synthesized. It appears to sound without actually being played. It is a resulting or resultant note. This gives tone and sonority to the instrument and builds the sound.
What becomes interesting also is when we sound together combinations such as 200 vibrations per second and 300 vibrations per second together. We also synthesize a sound at 100 vibrations per second. But the 200 vibrations per second string vibrates with harmonics
200 400 800 1000 1200
and the 300 string vibrates with the harmonics
300 600 900 1200
Then because 1200 vibrations is a harmonic of both strings, we will hear 1200 more strongly and it adds to the timbre, the tone, and can be heard sometimes as an extra note.
If we sound 500 vibrations per second with this then we add the harmonic series
500 1000 1500.
Then a note at 1000 is heard in addition to the note of 1200 and in addition to the 100 vibrations per second. So the timbre of the sound of the instrument becomes reinforced even more.
The problem with modern piano tuning is that the 300 500 600 700 frequencies are not tuned close enough to the perfect harmonic to add the sound reliably except in a jangling way.
As musicians we have experienced a shimmering or glistening to the sound of the piano. Then we say "what a wonderful piano". But by doing this the piano presents the piano rather than presenting the intended effect of the music.
2. Musically this has reduced the dimensions in which the music can speak, reducing them to
a. loud versus soft
b. slow versus fast
c. discordant versus harmonious
Have you read George Orwell 1984? The new language NEWSPEAK reduced the number of words to 300 so that people were limited by their language in their ability to think. This reduction of dimension in music has done the same to music.
3. The meaning of "Chromatic"
As musicians we have been bamboozled into thinking that the chromatic scale is simply going up each note by semitones C C# D D# E F F# G G# A A# B C.
We have forgotten what the language means.
Photographers who are old enough took photographs as transparencies for projection on film called . . . KodaCHROME EctaCHROME FujiCHROME and our lenses are CHROMATICally corrected - which means that on the edges of things in our image we don't see fringes of a spectrum of colours.
In the modern tuned instrument there is no hint of anything that we can call CHROMATIC demonstrating a spectrum of sound like a spectrum of colour.
3. The solution.
The tuning that I use exploits lots of perfect fifths (like F to C and E to B) in the exact ratios of 200:300.
This brings many "thirds" such as F-A and C-E and G-B near to the ratios 500:400. It is close so that it resonates without making other thirds unpleasantly too imperfect such as B-D#. This is enough to return the musical scale to giving a spectrum of "colour" to the chromatic scale. This is necessary for composers "HAYDN", "MOZART", "BEETHOVEN", "SCHUBERT", "CHOPIN" and "LISZT" whilst not doing damage to the music of later composers.
The spectrum of sound that we hear is demonstrated on https://youtu.be/qqS_IjKo-d8
The differences of sounds create a reward to the musician for playing sensitively, reacting to the different sounds differently as intended to be heard by the classical composers. Now the musician is rewarded in moulding the sound shapes in the phrasing of the music, conveying meanings unheard in modern tuning but intended to be heard.
We have a corpus of recordings, many of which are acclaimed by musicians who have heard them:
Music in "colour tuning"