What is this 60 chord system?
Hello ahuimanu, I am NOT an expert on theory, but here is the SIMPLE explanation of the 60 Chord system. Let me give you a little, although maybe not scientifically, but somewhat correct background first.
An Octave can be divided into an arbitrary quantity of tones. I say arbitrary, because in other cultures, the octave is divided into many different divisions, based on emotions, history, religion, culture, myth and other arbitrary reasons. Like in India, I believe the Octave is divided into over 100 tones.
In Western civilization music, the octave is divided into 12 tones by reason of MAHTEMATICS. Hence the name 12 tone system. Because of the evolution of mathematical tuning of these divisions, we can play in 12 keys today.
The original 12 tone division of an octave was devised by Pathagoras(proof of right triangle), although was altered mathimatically through time. During the early stage of tuning development, you could only play in ONE key. AND, the there was no standard for which tone was the starting point. At some point, 440-442hz became the standard for the Pitch we call "A".
During this evolution of divisions, 7 of these tones were to become what we know today as a diatonic scale. (Do, Re, Mi, Fa, So, La, Ti -octave Do)(Early pianos had ONLY octaves of these 7 tones.) During the early Christian history, certain combinations of these tones were actually banned by the Roman Catholic church, as they were thought to be inspired by the devil.
It is because of cultural indoctrination of these tones, that we become accustomed to our 12 tone system during childhood. It is NOT automatic. That is why other systems sound foriegn to our ears.
Original notation of a diatonic scale was for ONE octave.
A B C D E F G
As the evolution of tuning evolved, all 12 tones were to become what is known today as the CHROMATIC SCALE. But because labling of 7 tones had already been in use for centurys, and evolution of the piano, some of these notes became labled as SHARPS and FLATS(enharmonic) Hence:
A A#(Bb) B C C#(Db) D D#(Eb) E F F#(Gb) G G#(Ab)
At some point, construction of the Diatonic Scale could be built from the Chromatic Scale, on all 12 tones, by use of the following TONE STEP formula:
W W 1/2 W W W 1/2
where W= WHOLE TONE(or step)
1/2= HALF TONE(or 1/2 step)
There are many other formula for construction of other scales. However, for the sake of simplicity, I will stick to the DIATONIC.
Jumping a bunch of history, it was found that combinations of notes created what we know of today as CHORDS. Eventually, formulas for the creation of these combinations based on EACH DIATONIC SCALE were developed.
It was found that a combination of the FIRST, THIRD, and FIFTH tones of the Diatonic scale were the most pleasing.(arbitrary explanation)It is because of the OVERTONE tonal similarity that this occurs.
This combination became labled as a MAJOR chord.
The formula is 1-3-5
When you FLAT the THIRD, it now becomes a MINOR chord.
Hence...............1-b3-5
When you FLAT the FIFTH, it becomes a DIMINSHED chord.
These combinations are known as QUALITIES. There are TWO other qualities, however, the construction of the chords must be extended to the SEVENTH tone of the diatonic scale.
When you extend the previous qualities to a seventh STEP of the diatonic scale, you end up with these. I will use the Key of C as an illustration.
1 3 5 7 C E G B This is a MAJOR SEVENTH CHORD.
1 3 5 b7 C E G Bb This is a DOMINANT SEVENTH, as the 7 is flatted.
1 b3 5 b7 C Eb G B This is a MINOR SEVENTH, as both the 3 and 7 are flatted.
1 b3 b5 b7 C Eb Gb Bb This is a HALF DIMISHED, as the 3, 5 and 7 are ALL flatted.
1 b3 b5 bb7 C Eb Gb A This is a DIMINISHED, as the 3 and 5 are flatted, and the 7 is DOUBLE flatted.
This creates FIVE QUALITIES of CHORDS.
MAJOR, MINOR, DOMINANT, 1/2 DIMINISHED, DIMINISHED
These qualities are all based on intervals of MAJOR and MINOR THIRDS.
Hence........5 qualities x 12 keys= 60 CHORDS!!
Learn all 5 qualities of chords with the ROOT TONE based on the 12 Chromatic TONES, and you will begin to see.
Learn these qualities on every place on the fretboard, and you will be on your way to knowing your fretboard.
Learn ALL 7 of the SCALE TONE SEVENTH CHORDS in ALL TWELVE KEYS, and you will begin to HEAR where progressions are going.
SCALE TONE SEVENTH CHORDS are based on extending each chord to a SEVENTH STEP, using the diatonic scale: Starting from C, build the FIRST DIATONIC SCALE.
C (W) D (W) E(1/2)F(W) G(W)A(W)B(1/2)---(octave!) C
Do this with ALL 12 Chromatic scale, MEMORIZE THEM, learn them at ALL 8 positions on the fretboard, and you will have become FAMILIARIZED with your fretboard.
Now build the chords from EACH of the 7 DIATONIC SCALE tones Starting with C(no flats or sharps)
1 2 3 4 5 6 7 (1)
C D E F G A B (C)
I 1357 CEGB "C" MAJOR SEVENTH
II 2461 DFAC "D" MINOR SEVENTH(build a "D" scale to see why
III 3572 EGBD "E" MNOR SEVENTH(build an "E" scale to see why
IV 4613 FACE "F" MAJOR SEVENTH(same as I in an F scale
V 5724 GBDF "G" DOMINANT SEVENTH(build a "G" scale to see why
VI 6135 ACEG "A" MINOR SEVENTH((build an "A" scale to see why
V11 7256 BDFA "B" HALF DIMINISHED(build a "B" scale to see why
Build, Memorize and Play in all positions on the fretboard, and you will have begun you journey on the 60 Chord system. Enjoy. PS, if you can figure out why there are no DIMINISHED chords in the diatonic system, you will have figured out what I have told you.
fitZ
NOT!! A blues is based on dominant 7ths. This implys all the scale tone chords are extended to a seventh. The only roman numeral that is a dominant seventh is a V. I and IV are major sevenths. Johnny B Goode would sure sound wierd using MAJOR SEVENTHS. To notate the blues in Roman Numerals, you have to EITHER alter the I and IV to a dominant, or THINK in terms of all chords as a V in different keys. For instance, since I and IV are MAJOR chords, HOW would you notate this correctly IF it were a MINOR BLUES, and had other altered chords? This is why people who don't know the 60 chord system can get confused with standard Nashville notation. Not only that, if you think about it, to play within appropriate scales(besides pentatonics)to a standard blues tunes, ALL the chords ARE a V in different keys. For instance, here is a blues in A.
Let alone notating a SHARPED DIMINSHED CHORD!
Thats why I am not an expert on the subject. But I've been using this system as I know it for 20 yrs.
