Did you know that you can easily find the correct family of chords for a major scale? Let's start with the C major scale for an example. To find the 7 triads:
Start with c and choose every other ascending note until you have 3 notes. You should end up with c, e, and g. Those notes make a C major chord.
Now start with the next note (d) and choose every other ascending note until you have 3 notes. You should end up with d, f, and a. Those notes make a D minor chord.
Now start with the next note (e) and do the same thing. That gives you e, g, and b. Those notes make an E minor chord.
Now start with the next note (f) and do the same thing. That gives you f, a, and c. Those notes make an F major chord.
Now start with the next note (g) and do the same thing. That gives you g, b, and d. Those notes make a G major chord.
Now start with the next note (a) and do the same thing. That gives you a, c, and e. Those notes make an A minor chord.
Now start with the last of the 7 scale degrees (b) and do the same thing. That gives you b, d, and f. Those notes make a B diminished chord.
Here are the triads we just constructed:
c e g = C
d f a = Dm
e g b = Em
f a c = F
g b d = G
a c e = Am
b d f = Bdim
For 7th chords, do the same thing you did with the triads - choose every other ascending note - but until you have 4 notes.
For 9th chords, choose every other ascending note until you have 5 notes.
For 11th chords, choose every other ascending note until you have 6 notes.
For 13th chords, choose every other ascending note until you have 7 notes.
Here are the 7th chords we just constructed:
c e g b = CM7
d f a c = Dm7
e g b d = Em7
f a c e = FM7
g b d f = G7
a c e g = Am7
b d f a = Bm7b5
Here are the 9th chords we just constructed:
c e g b d = CM9
d f a c e = Dm9
e g b d f = Emb9
f a c e g = FM9
g b d f a = G9
a c e g b = Am9
b d f a c = Bm7b5b9
Here are the 11th chords we just constructed:
c e g b d f = CM11
d f a c e g = Dm11
e g b d f a = Em11b9
f a c e g b = FM11
g b d f a c = G11
a c e g b d = Am11
b d f a c e = Bm11b5b9
Here are the 13th chords we just constructed:
c e g b d f a = CM13
d f a c e g b = Dm13
e g b d f a c = Emb13b9
f a c e g b d = FM13
g b d f a c e = G13
a c e g b d f = Amb13
b d f a c e g = Bmb13b5b9
These are all "consonant" (as opposed to "dissonant") chords because they all use only the 7 notes of the C major scale and therefore sound "harmonious" or "in agreement" with the major scale.
Start with c and choose every other ascending note until you have 3 notes. You should end up with c, e, and g. Those notes make a C major chord.
Now start with the next note (d) and choose every other ascending note until you have 3 notes. You should end up with d, f, and a. Those notes make a D minor chord.
Now start with the next note (e) and do the same thing. That gives you e, g, and b. Those notes make an E minor chord.
Now start with the next note (f) and do the same thing. That gives you f, a, and c. Those notes make an F major chord.
Now start with the next note (g) and do the same thing. That gives you g, b, and d. Those notes make a G major chord.
Now start with the next note (a) and do the same thing. That gives you a, c, and e. Those notes make an A minor chord.
Now start with the last of the 7 scale degrees (b) and do the same thing. That gives you b, d, and f. Those notes make a B diminished chord.
Here are the triads we just constructed:
c e g = C
d f a = Dm
e g b = Em
f a c = F
g b d = G
a c e = Am
b d f = Bdim
For 7th chords, do the same thing you did with the triads - choose every other ascending note - but until you have 4 notes.
For 9th chords, choose every other ascending note until you have 5 notes.
For 11th chords, choose every other ascending note until you have 6 notes.
For 13th chords, choose every other ascending note until you have 7 notes.
Here are the 7th chords we just constructed:
c e g b = CM7
d f a c = Dm7
e g b d = Em7
f a c e = FM7
g b d f = G7
a c e g = Am7
b d f a = Bm7b5
Here are the 9th chords we just constructed:
c e g b d = CM9
d f a c e = Dm9
e g b d f = Emb9
f a c e g = FM9
g b d f a = G9
a c e g b = Am9
b d f a c = Bm7b5b9
Here are the 11th chords we just constructed:
c e g b d f = CM11
d f a c e g = Dm11
e g b d f a = Em11b9
f a c e g b = FM11
g b d f a c = G11
a c e g b d = Am11
b d f a c e = Bm11b5b9
Here are the 13th chords we just constructed:
c e g b d f a = CM13
d f a c e g b = Dm13
e g b d f a c = Emb13b9
f a c e g b d = FM13
g b d f a c e = G13
a c e g b d f = Amb13
b d f a c e g = Bmb13b5b9
These are all "consonant" (as opposed to "dissonant") chords because they all use only the 7 notes of the C major scale and therefore sound "harmonious" or "in agreement" with the major scale.
