Key Finding Using Minor Chords
24 October 2017
There are many ways to find determine what key you are in.
This method uses a minor triad, and assumes you know a little bit about the MAJOR SCALE CHORD FORMULA.
3 Minor Chords
In the major scale there are three places (or slots) where a minor chord can be found:
- Using the C Major Scale Notes: C, D, E, F, G, A, B...
- ...Convert the C Major Scale Notes to Intervals (Slots): 1, 2, 3, 4, 5, 6, 7...
- ... match the intervals to the chords derived from the Major Scale Chord Formula: M, m, m, M, M, m, Dim
Can you see that you would have Dm, Em , and Am, using slots (intervals) 2, 3, and 6?
D minor, E minor, and A minor
So my minor chords are Dm, Em, and Am.
I will use a chord shape where the root note is on the first string (just because):
Dm has the notes:
- D, F, A
Em has the notes:
- E, G, B
Am has the notes:
- A, C, E
So now, I add notes on the 1st and 2 strings to make a visual reference that will allow me to compare the three chords against each other.
(I am still using notes from the C Major Scale)
Notes as Intervals
Next up I convert the notes to intervals. For the Dm chord, I treat D as the root note. For Em, I treat E as the root note. For Am, I treat A as the root note. The reason is that I want to find the intervals of the notes relative to my current chord. Not relative to any scale - remember that we might not know the scale, that is why we are doing this exercise.
The intervals for each note relative to its chord:
- 1, 2, b3, 4, 5, 6, b7
- 1, 2b, b3, 4, 5, 6b, b7
- 1, 2, b3, 4, 5, b6, b7
So look at the differences.
- Dm is the only one with a natural 6.
- Am and Em have b6
- Em, has a b6 but ALSO has a b2. It is the only one with a b2
So what does this mean?
- Dm is in the 2nd slot of the C Major Scale.
- Em is in the 3rd slot.
- Am is in the 6th slot.
The really common minor chord is the one with the 6th: If you play a minor chord, and the 6 sounds cool then it is like playing the Dm shown above, and therefore you are in the second slot of the Major scale.
The next reallly common chord is the one with the b6: If you play a minor chord, and the b6 sounds cool then it is like playing the Am shown above, and therefore you are in the sixth slot of the Major scale.
The least common chord is the one with the b2: If you play a minor chord, and the b2 sounds cool then it is like playing the Em shown above, and therefore you are in the third slot of the Major scale.
Of course, this might take a bit of practise, but it is worth it and becomes a really easy tool/trick.