General Chord Theory

This is a general introduction to what chords are, and what you might do with them. The information in this lesson is terse, as most if not all of the ideas have been or will be explained in greater detail in the other chord lessons (found at the above chord site). Some of the material is general and applies to all instruments, some is specific to the guitar. I'll try to differentiate for the reader.

What is a chord?

A chord is a type of harmonic structure (general and obscure).

A chord is a harmonic structure consisting of 3 or more tones ringing simultaneously.

okay. So what is a harmonic structure?
A harmonic structure is a group of tones played as harmony (as opposed to being played as melody).

So how is a chord different from other types of harmonic structures?
- a chord consists of 3 or more tones.
Fewer than 3 tones would be non-chordal. For example you could have two tones (such as a dyad or harmonic interval), or one tone (such as a choir of 200 people singing in unison).

What do you mean ringing simultaneously?
- The notes should be played in such a way that the tones ring at the same time though they need not start or end at the same time. If they ring one at a time and not at any time together, then you no longer have harmonies, and it would be considered an arpeggio (or maybe even a scale).

Consider,
the m7/11 chord = 1,b3,5,7,11
the m7/11 arpeggio = 1,b3,5,7,11
the pent.min.scale = 1,b3,4,5,7

Dm7/11 chord
|--5--|
|--6--|
|--5--|
|--5--|
|--5--|
|-----|

Dm7/11 arpeggio
|----------5--|
|--------6----|
|------5------|
|----5--------|
|--5----------|
|-------------|

D pent.min.scale
|-------------|
|-------------|
|----------5--|
|------5-7----|
|--5-8--------|
|-------------|

D pent.min.scale (in double-stops)
|---------------|
|----------6-8--|
|------5-7-5-7--|
|--5-7-5-7------|
|--5-8----------|
|---------------|

The same notes are involved but they may be seen as harmonic or melodic structures depending on how they're played. The last example is the pent.min.scale in double-stops, which is a harmonioc way of playing scales.

Non-guitar-specific aspects of chords
(methods of chord construction, extensions and alterations, polychords, alternate harmonization schemes, progressions, substitution, modulation, Chord-melody, block chords vs: arpeggios, voice-leading)

CHORD CONSTRUCTION
There are several ways to create chords including:
satcking 3rds, creating from scales, collecting intervals, random generation, alternate harmonizations, etc.

Briefly looking at some of these:

Stacking 3rds:
Take a 3rd (M3, m3, etc.) and using the top note create another 3rd on top of it. This will create a triad ( a 3-note chord).

Some common chords built this way:

Stacking a m3 on top of a M3 creates a major triad.
C to E = M3, E to G = m3
C,E,G = C major triad (C major chord, C)

Stacking a M3 on top of a m3 creates a minor triad.
C to Eb = m3, Eb to G = M3
C,Eb,G = C minor triad (C minor chord, Cm)

Stacking a m3 on top of a m3 creates a diminished triad.
C to Eb = m3, Eb to Gb = m3
C,Eb,Gb = C diminished triad (C diminished chord, Co)

Stacking a M3 on top of a M3 creates an augmented triad.
C to E = M3, E to G# = M3
C,E,G# = C augmented triad (C augmented chord, C+)

Creating chords from scales:
The previous definitions are often applied to scales by stacking the scale upon itself.

If we take the major scale and stack the scale on itself in 3rds (called tertian harmonization) we get (first) intervals (3rds) whose tones are in the scale (here C major)


|-------------------------------|
                              O
|-------------------------O-----|
                      O       O
|-----------------O-------O-----|
              O       O
|---------O-------O-------------|
      O       O
|-O-------O---------------------|
      O
 -O- 
 M3  m3  m3  M3  M3  m3  m3  M3


Then triads (M=maj, m=min, o =dim, +=aug)

                              O
|-------------------------O-----|
                      O       O
|-----------------O-------O-----|
              O       O       O
|---------O-------O-------O-----|
      O       O       O
|-O-------O-------O-------------|
      O       O
|-O-------O---------------------|
      O
 -O- 
  M   m   m   M   M   m   o   M


Then 7th chords (M7=maj7, m7=min7, 7=dom7)
                              O
                         -O-
                      O       O
|-----------------O-------O-----|
              O       O       O
|---------O-------O-------O-----|
      O       O       O       O
|-O-------O-------O-------O-----|
      O       O       O
|-O-------O-------O-------------|
      O       O
|-O-------O---------------------|
      O
 -O- 

 M7  m7  m7  M7  M7  m7 m7b5 M7

This can be continued through more extensions (9th chords, 11th chords, 13th chords).

Collecting intervals:
You can choose to play any 3 or more notes that you wish together. One can view a chord as not needing a context (such as a scale or stacking intervals). A chord can be seen as a set of notes. Based on personal preferences you could choose to combine various intervals from the root note.

ex. G to C#, G to D,
G,C#,D = XX5633

Extensions/alterations:
Taking a chord and adding extra notes (extensions) to it creates larger chords.
Some typical definitions of some groups of chords:

7th chords (maj7,7,m7,m7b5,o7,etc.) contain a root note, some 3rd, some 5th, some 7th.
ex. maj7 contains root,M3,p5,M7

9th chords (maj9,9,m9,m7b9,etc.) contain a root note, some 3rd, some 5th, some 7th, some 9th.
ex. dom9 contains root,M3,p5,m7,M9

11th chords (maj11,11,m11,M9#11,etc.) contain a root note, some 3rd, some 5th, some 7th, some 9th, some 11th.
ex. maj9#11 contains root,M3,p5,M7,M9,aug11

13th chords (maj13,13,m13,m11b13,etc.) contain a root note, some 3rd, some 5th, some 7th, some 9th, some 11th, some 13th.
ex. m13 contains root,m3,p5,m7,M9,M11,M13

Alterations are taking an existing chord and changing one or more notes to create a different chord.
ex.
9 = 1,3,5,b7,9
7#9 = 1,3,5,b7,#9

Polychords:
Combining a chord with other notes or even other chords to create new chords.
ex.
C5/G5 = 3X0013
D/G(maj) = 320232

Alternate harmonizations:
There are several other ways to create chords such as harmonizing a scale in different intervals than 3rds.

ex. from stacked 4ths:
Cmaj7(4) = X3345X
ex. from stacked 5ths:
Aadd9(no5) = 579XXX

Random generation
there are extremly random ways to create chords such as assigning numbers 1-12 to notes and rolling dice (or drawing cards from a deck). Then there's the schillinger system... , tone rows... ,etc. The most common forms of randomly generated chords are either hearing the sounds in your head and expressing them, or accidently creating a chord.

*note: if you want to communicate your chords with others, you'll need to understand the more common forms of chord construction (tertian harmonization) and how they can be adapted (extensions, polychords, alterations, omissions, synonyms, etc.)

Substitutions
Some chords can easily replace other chords or achieve the same or similar effects. For example, Am7 and C6 contain the same notes (chords synonyms) and can be substituted for the other. Other rules and opinions on substitution exist.

Progressions
String a group of chords together, and the specific path they take is called a progression. Many popular songs can be broken down into a handful of common progressions such as I-IV-V (which in the key of C would be C-F-G) or ii-V-I (in C: Dm-G-C)

Modulation
The change of keys. Such changes are often emphasized with progressions (cadences) that resolve to the tonic (root) of the new key.

Chord-Melody
An imitation of piano-style playing where chords and melody are played at the same time.

Block chords vs: arpeggios
A particular voicing of a chord could be played all notes at once (block chords) or one note at a time (arpeggio).

Voice leading
is the treatment of viewing the notes in chords as notes of melodies, and the crafting of voicings of chords in progressions to respect this.

Guitar-specific information
(fingerings, string attack)

The application of chords to the guitar can be split into the specific fingering of the instrument (abstracted by chord diagrams, TAB, fretboard maps) and the attacking of the strings (using picks, fingers, or induced vibration)

Chord Diagrams and fretboard maps
Exactly why the notes are in specific locations on the fretboard is due to the tuning used. Changing the tuning will change the relative string/fret/note relationships. One of the advantages of playing a fretted string instrument is the ability to play multiple chords with the same shape (moveable shapes, barre chords, etc.)

String attack
- using a pick
chords can be strummed (block chords) or arpeggiated with a pick
- using fingers
chords can be fingerpicked or tapped
- induced vibration
strings can be induced to ring by means of other strings moving
(sympathetic strings) or using a magnet along w/ pickups (e-bow, etc.)

Chord books and their use
Various authors have published collections of chord diagrams. This can be valuable for a beginning guitarist who doesn't posses the knowledge of chord construction, or understand how the fretboard is laid out. The usefulness of any chord dictionary can be increased by somehow denoting which notes are the root notes, and viewing the chords as moveable shapes.

A small chord syllabus
Here is a listing of several common chord types defined by their intervals with no reference to any specific key.

major = 1,3,5
minor(m) = 1,b3,5
power(5) = 1,5,8(1)
diminished(o) = 1,b3,b5
augmented(+) = 1,3,#5
sus2 = 1,2,5
sus4 = 1,4,5
dom7(7) = 1,3,5,b7
maj7 = 1,3,5,7
m7 = 1,b3,5,b7
m7b5 = 1,b3,b5,b7
dim7(o7) = 1,b3,b5,bb7
7sus4 = 1,4,5,b7
dom9(9) = 1,3,5,b7,9
maj9 = 1,3,5,7,9
m9 = 1,b3,5,b7,9
dom11(11) = 1,3,5,b7,9,11
maj11 = 1,3,5,7,9,11
m11 = 1,b3,5,b7,9,11
dom13(13) = 1,3,5,b7,9,11,13
maj13 = 1,3,5,7,9,11,13
m13 = 1,b3,5,b7,9,11,13
6 = 1,3,5,6
m6 = 1,b3,5,6
6/9 = 1,3,5,6,9
7/11 = 1,3,5,b7,11
add9 = 1,3,5,9
add4 = 1,3,4,5
7#9 = 1,3,5,b7,#9
7b9 = 1,3,5,b7,b9
maj7/#11(maj7#11) = 1,3,5,7,#11

For those interested, here's a brief outline of chord studies.
(one way to approach it, other teachers might emphasize things at different times, etc.)

---Beginner's studies---
- Be able to read diagrams and TAB
- Know how to place fingers down on the fretboard
- Learn/ memorize basic chords
- Learn simple strumming and fingerpicking techniques
- Simple chord changing
- Know how to use a chord book

---Intermediate studies---
- Locating root notes
- How to play and use barre chords
- Learning intervallic spellings of chords
- Learning how to build chords
- Knowing how to create voicings
- Understanding and applying progressions
- Learning to make your own chord diagrams/ frteboard maps
- Knowing how to make the most out of chord books
- Understanding chord synonyms
- reading chords from standard notation and sight-reading in open position

---Advanced studies---
- Understanding extended and altered chords
- Alternate harmonization schemes
- Sightreading chords in standard notation in higher positions
- Chord-melody studies
- Understanding and applying chord substitution
- Understanding the wave basis for chord construction (harmonic series, etc.)
- Orchestration and arranging

---Beyond that?---
- Creating a personal style
- Polyphony
- Improvisation, being able to play what's in your head
- Manipulating emotions, understanding the effect of tone on the psyche
- Music therapy, using tones to cure body, mind, and spirit
- Allowing the music to use you as it's tool
- Finding the instruments/tunings voice, and allowing it to speak

An alternate simplification I like is (to paraphrase Robert Fripp)
The beginner learns to make noise
The intermediate crafts sounds
The advanced crafts silence
the master plays silence

The next lesson is on major chords.

Peace,
Christopher Roberts


How do I change all those numbers to letters (for notes, chords, etc.)? Here's a transposition chart simianmoon.com/snglstringtheory/guitar/8theory3.html

Back to the Chord lesson index

Next Lesson - Major chords
Previous Lesson - Intervals, pt.2
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Last updated December 31, 2002.
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