Music Theory 1 (Chord Theory)

Question 1

What notes make up a major triad?

Answer 1

Root, major third, perfect fifth.
1 3 5

Major triad formula: Major third + minor third
C (M3) E (m3) G

Question 2

What notes make up a minor triad?

Answer 2

Root, minor 3rd, perfect 5th.
1 b3 5

Minor triad formula: minor 3rd + Major third
A (m3) C (M3) E
D (m3) F (M3) A
E (m3) G (M3) B

Question 3

What notes make up a diminished triad?

Answer 3

Root, minor 3rd, diminished 5th.
1 b3 b5

Diminished triad formula: minor 3rd + minor third.
B (m3) D (m3) F

Question 4

What notes make up an augmented triad?

Answer 4

Root, major 3rd, augmented 5th.
1 3 #5

Augmented triad formula: major 3rd + major 3rd
C (M3) E (M3) G#

This triad is not derived from the diatonic (major) scale. Almost like a musical question mark.

Used to create a suspended or mysterious sound.

Question 5

What diatonic chords are formed when harmonising the major scale?

Answer 5

I - Major
ii - minor
iii - minor
IV - Major
V - Major
vi - minor
vii - diminished

Question 6

What are the five main types of seventh chords?

Answer 6

. Major 7th

2. Minor 7th
3. Dominant 7th
4. Half-Diminished 7th
5. Diminished 7th

Question 7

How is a major 7th chord constructed?

Answer 7

Root, major 3rd, perfect 5th, major 7th
1 3 5 7

Formula: major 3rd, minor 3rd, major 3rd
C (M3) E (m3) G (M3) B

Sounds very pretty and rich. Frequently heard in jazz and RnB styles.

Sounds like it has more tension/dissonance due to that semitone interval between the leading note and the tonic.

Question 8

How is a minor 7th chord constructed?

Answer 8

Root, minor 3rd, perfect 5th, minor 7th
1 b3 5 b7

Formula: minor 3rd, major 3rd, minor 3rd
C (m3) Eb (M3) G (m3) Bb

Sounds

The greater distance between leading note and the tonic (a tone) creates more space, compared to the major 7th’s semitone gap.

Question 9

How is a dominant 7th chord constructed?

Answer 9

Root, major 3rd, perfect 5th, minor 7th
1 3 5 b7

Formula: major 3rd, minor 3rd, minor 3rd
C (M3) E (m3) G (m3) Bb

Sounds like it wants to resolve to the tonic chord. It sounds like an inbetween major and minor sound.

They strongly establish a sense of resolution back to the tonic chord. This is because the notes of the dominant 7th strongly resolve to the tonic:
the first note of the V7 is the highest note of the tonic triad,
The 3rd note of the V7 is a semitone below the tonic,
the b7 of the V7 is a semitone above the 3rd of the tonic.
e.g.
I - C E G
V7 - G B(semitone below) D F(semitone above)
I - C E G

Question 10

How is a half-diminished 7th chord constructed? (i.e. Minor 7th Flat 5)

Answer 10

Also knows as the Minor 7th Flat 5. (common in jazz)

Called half-diminished as it has a flattened 7th as opposed to the double flatted 7th of the fully diminished chord.

This uses the diminished triad as its base.

Root, minor 3rd, diminished 5th, minor 7th
1 b3 b5 b7

Formula: minor 3rd, minor 3rd, major 3rd
C (m3) Eb (m3) Gb (M3) Bb

Question 11

How is a diminished 7th chord constructed

Answer 11

This uses the diminished triad as its base, and the 7th is double flatted (lowered by two semitones).

Root, minor 3rd, diminished 5th, diminished 7th
1 b3 b5 bb7

Formula: minor 3rd, minor 3rd, minor 3rd
C (m3) Eb (m3) Gb (m3) Bbb (or A)

It contains two tritones - C-Gb (tritone), and Eb-Bbb (tritone).

This chord is symmetrical. A common technique to create mystery and suspense is to keep moving it up by minor thirds i.e. its inversions:
C Eb Gb Bbb, Eb Gb Bbb C, Gb Bbb C Eb etc.