All it is: 7 notes, 7 chords

Everything in music is referenced to the 7 white or natural notes, looking at the usual music keyboard.


C D E F G A B or do re mi fa sol la si


Even an F sharp or F# or B flat or Bb for example, they are still F or B.


All melodies can be played with just these 7 white or natural notes.


Why is its so difficult then to play music?


Because a beginner will start playing a melody from a random note. It can still be played but the choice of a random note will define a scale which might be a difficult one. For example any C may then have to be sharp, any F may have to be sharp, any G may have to be sharp.


But if for example we begin "Happy Birthday...) by the note G it is very easy as this happens when the scale or key is C major and all notes are natural or white. We may transport all melodies to the C major key but this is not a good idea as the key sets the mood, the ambience, the atmosphere of the piece. For example it is very difficult or even funny to listen to Moonlight Sonata - Beethoven to any key different from the original C sharp minor key. Still Beethoven uses just those 7 notes but some of them need to be sharp or #. C is C#, D is D#, E is natural, F is F#, G is G#, A is natural, B is natural. The familiar beginning of Moonlight Sonata is G C E, G C E, G C E,...,etc. And of course G is sharp and C is sharp. The bass is C sharp as usually musical pieces begin with a bass note same as the key on which they are written. In fact this is the key that opens to our brain the door to the musical atmosphere. So even in such a difficult piece all we have in the beginning in a C bass and the notes G C E on the right hand. Note the right hand notes can be written C E G. So to get to the roots all we have is C bass and C E G on the right hand. Of course in this particular key all G and C are sharp as we have said above. Note C E G is just the numbers 1 3 5 above the bass. By counting from the bass C is 1, E is 3, G is 5. This is called a harmonic triad.


Happy birthday begins with the same harmonic triad. Bass is C, chord is C E G. But they are all natural as the key of Happy Birthday may be C major ie all the natural (white) notes.


Now that we know that almost every melody can be played with just 7 notes, the same applies naturally to chords. They are only 7, seven harmonic triads.


Which are they?


It is easy. We take all 7 notes, each as bass and then 1 3 5.


So all the chords on our planet are:


C E G
D F A
E G B
F A C
G B D
A C E
B D F


Using these we can play almost everything on our planet. But we need to know the key so that we know which of the notes are natural and which are sharp or flat.


For example on Happy Birthday or Imagine - John Lennon both written in C major all notes are white and all we have to try is find the right bass every time by trial and error and and add 1 3 5 without warning about flats or sharps.


For example Imagine begins naturally with C bass and naturally C E G on the right hand. The next chord is bass code F ie F bass F A C on the right hand. But John Lennon plays C F A which are the same notes in a more suitable order as the hand moves the least from the previous C E G and it sounds natural and brilliant.


Same with Moonlight Sonata and every piece on the planet.


For example on Moonlight Sonata bass is C. So the default code gives C E G for the right hand. But Beethoven plays G C E which again are the same notes in different order. And this is what he liked. And what we also like. He is also doing a fabulous trick of keeping the right hand the same while the bass descends the notes of the scale. The least changes in music have the most profound unexpected and mysterious effect to our brain.


And this brings us to the fact that not all code is 1 3 5. It can be 1 3 7, just called 7, 1 3 9 just called code 9. It can be 2 4 6 the second chord of Moonlight Sonata as only bass goes down one step and the right hand stays the same. For example C7 means C bass and we have on the right hand B which is the 7th note and E with is the 3rd. The 3rd makes the 7th sound brilliant. For example we have code C7 where the lyrics are Far Away Across the Fields on the Pink Floyd's Dark Side of the Moon album. Roger plays C on the bass, Rick plays E G B (3 5 7) in the organ, Dave sings the word Far with B, the 7th interval from bass. The key is the Hellenic Dorian. It is E Dorian so only F and C are sharp. Therefore on the above example Pink Floyd play all white notes at that particular moment in time. Where do particular chords come from or how music is composed? Difficult to answer but at least Pink Floyd had only to choose between only 7 chords as any composer does. They added the 7th ie C bass with E G B to create the mystery that cannot be described with words. We may like to think that all the 1 3 5 code is the pasta, or pastry and the rest of the code is the spices or the non standard ingredients. Still we can play everything with just code 1 3 5. But the rest of the code is the fine subtle details that can make all the difference. And Bach was saying that Gid is in the details.


The person to explain further is Johann Sebastian Bach as he did to his other students and you will find the manual that changed the way classical and pop music sounds on our planet in the reference. It can also be found at the appendix of the Bach biography by Spitta.


Reference:


Bach Bass Rules:
https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf