What is a Chord?
A chord is the simultaneous sounding of three or more pitches. The first chords we learn are the triads, where each note is separated by the interval of a third.
In these triads, the first note is called the root (or fundamental), the second is called the third (because it is an interval of a third above the root), and the third note is called the fifth (because it is an intervals of a fifth above the root).
Four types of triads
- Major Triad: Formed by a Major 3rd and a Perfect 5th.
- Minor Triad: Formed by a Minor 3rd and a Perfect 5th.
- Augmented Triad: Formed by a Major 3rd and an Augmented 5th.
- Diminished Triad: Formed by a Minor 3rd and a Diminished 5th.
Chords in scales
In every major scale, we can form seven unique chords, one for each scale degree. Each chord takes its name from the degree it is built upon.
Chords I, IV, and V are known as the Primary Chords, while the others are called Secondary Chords.
Why are they “Primary”?
These three chords contain every single note of the scale. This allows them to fully define and establish the tonal center (the key) of a piece of music.
Chord Inversions
A chord doesn’t always have to be played with the root at the bottom. By changing the lowest note (the bass note), we create inversions, which change the “weight” and flow of the chord without changing its name.
- Root Position (5/3):
When the root is the lowest note, the chord is in Root Position.
The numbers 5/3 (five-three) are the intervals of a fifth and a third above the the bass. - First Inversion (6/3):
When the third is the lowest note, the chord is in First Inversion.
The numbers 6/3 (or simply 6). The notes above this bass note now form an interval of a sixth and a third. This version sounds lighter and less “final” than the root position. - Second Inversion (6/4):
When the fifth is the lowest note, the chord is in Second Inversion.
The numbers 6/4 (six-four) are the intervals of sixth and fourth, above the bass. This is the most unstable inversion and usually “wants” to resolve to a Root Position chord.
Classical and Modern
Μusicians use two main systems to identify inversions.
In Classical Theory, we use Figured Bass. These are numbers that indicate the exact intervals (the distance) between the lowest note and the notes above it.
In Modern Music, such as Jazz, Rock or Pop, we use Slash Chords. These simply tell us the name of the chord and which note is in the bass.
So, Root Position the Figured Bass uses 5/3, while Slash Chords simply use the chord name, C.
First Inversion the Figured Bass uses 6/3, or just 6, and the Slash Chords is C/E. This literally means: Play a C Major chords with a E in the bass.
Second Inversion the figured bass uses 6/4, and the Slash Chord is C/G, so “Play a C Major chords with a G in the bass”.
Additional Chord Classifications
Furthermore, beyond the four types, chords can be categorised based on their sound, their notes, and their relationship to the scale:
1. Enharmonic Chords (Εναρμόνιες)
Just as we saw in the chapter on tones and semitones, enharmonic chords are chords that have different note names but sound exactly the same. They are the same keys on the piano, but written differently on the staff.
Example:
F# Major vs. Gb Major: Both chords use the exact same keys on a piano, but F# Major is written with 6 sharps, while Gb Major is written with 6 flats.
C# Major vs. Db Major: These sound identical in pitch but are notated differently based on the key of the piece.
2. Consonant Chords (Σύμφωνες):
These are chords using consonant intervals (like major and minor 3rds, perfect 5ths, and octaves). They sound stable, pleasing, and “at rest” to the ear. Major and minor triads are the primary examples.
Example
C Major Triad (C – E – G): A classic consonant chord because it consists of stable intervals like the major third and perfect fifth.
A Minor Triad (A – C – E): Though it has a “sad” quality, it is a consonant because its intervals are all stable.
3. Dissonant Chords (Διάφωνες)
These chords contain dissonant intervals, like seconds, sevenths, or tritone. They create tension and a feeling of “instability”, ;often sounding like they need to resolve to a consonant chord.
Example
G7 (Dominant 7th): The interval between the 3rd (B) and the 7th (F) is a tritone, which creates a strong dissonant pull that wants to resolve to C Major.
B Diminished (B-D-F): This triads contains a diminished fifth (a dissonance), giving it a tense, unresolved character.
4. Diatonic Chords (Διατονικές)
These are chords built using only the notes found naturally within a specific diatonic scale (the notes in the key signature). They stay “inside” the key without using any outside accidentals.
Example:
G Major in the key of C: This is the V chord of the C major scale, built naturally using only the white keys.
D Minor in the key of C: This is the ii chord, another purely diatonic chord that fits perfectly within the key signature.
5. Altered Chords (Αλλοιωμένες)
These are chords that contain one or more notes modified by an accidental (a sharp or flat) that is not in the original scale. These “borrowed” or “chromatic” notes change the interval structure to add more colour or tension to the harmony.
Example
G7(#5): A standard G7 chord where the natural 5th (D) is raised by a semitone to D#, creating a tense, “spicy” jazz sound.
C7(b9): A dominant chord where the 9th (D) is lowered to Db, adding a chromatic colour not found in the original scale.