playcreativepiano.com - Modern Tonal Harmony

quote by Hans Irgend BlumenfeldModern tonal Harmony, i'm really afraid about what some call 'modern', be carefull, there are classic examples of people who have failed trying this. But to sell books for the unfaithful, everything is worth.
From earliest times, harmony speaks in voice doubling, that is, repeat a note above or below inside an octave, we all know this is four part harmony, using triads, but what is the 7th chord with all different notes. What is the 'diminished seventh chord'?
It is good to remember that the author calls the note, when the same note name do not repeated, because, modern is even thinking of frequencies.
He says: "In modern harmony, chords are built simultaneously combining 4 different notes..."
'Bach' did this modern around 1705, when even in the 'Vi chord' he used the minor seventh.
Also 'Chopin' did it around 1830-31in his major 'Polonaise', after that he used 5 notes to be played by the same right hand that must use the thumb for this feat. After him, Debussy and Ravel orchestrations are five notes chords.
And Sebastian Erard's Romantic Pedal Harp presented in 1810, naturally produces, without any effort, four distinct notes by chord and natural arpeggios with 5+, 6ths, 9ths, b9ths, 13ths and b13ths, which amazing sonority that Ravel will listen to and make the most of his music.
The way we use the harmony today, since the the beginning of the 20th century, was cataloged by John Mehegan, which is the harmonious field with 4 distinct notes. But all this, it was only a matter of time to be used, because it is just note addition.
By the way the 'X' symbol for the dominant chord of the Menegan never caught, nobody used.
So we have to be careful about what is modern. In relation to what?