Scale Harmonisation

What Is Key Construction?

When you construct a key, you take the scale (in our case we'll be using the major scale) and build a chord from each of the 7 notes of that scale. The chord that you build can only use notes that are in that scale. For example, if you are using the key of C major, all of the chords must be built from the notes within the scale of C major. This is why the chords within the key of C major all work together and can be classed as being in the same key. Simple enough on the face of it right? Well, in the next lesson we will start putting this into practice to show you more clearly how it works!

The 1st Degree

We start by writing out the C major scale as we are currently working out the chords within the key of C major. We then want to build a triad chord (a 3 note chord) from each degree of the scale. Taking the first degree, C, as an example, the process will be to work out the C major chord, C minor chord and C diminished chord and see which one we can use. The one we can use will only contain notes that are in the C major scale. So let's have a look:

So we can clearly see that the C major chord fits into the key of C major as all 3 notes fit perfectly into our C major scale. The scale is C D E F G A B C, and in the C major chord, the notes are C, E and G. Perfect! Therefore the first chord of our key is C major.

The 2nd Degree

We now want to move to the second degree of the major scale, which in this case is D. We need to now write down the D major scale so that we can work out the three triad chords. They look like this:

We can clearly see that the D minor chord will fit into the key of C major as all 3 notes fit perfectly into our scale. The scale is C D E F G A B C, and in the D minor chord, the notes are D, F & A. Perfect! Therefore the second chord of our key is D minor.

The 3rd Degree

We now want to move to the third degree of the major scale, which in this case is E. We need to now write down the E major scale so that we can work out the three triad chords. They look like this:

So we can clearly see that the E minor chord will fit into the key of C major as all 3 notes within the chord are in the scale. The scale is C D E F G A B C, and in the E minor chord, you have an E, G & B. Perfect! Therefore the third chord of our key is E minor.

The 4th Degree

We now want to move to the fourth degree of the major scale, which in this case is F. We need to now write down the F major scale so that we can work out the three triad chords. They look like this:

So we can clearly see that the F Major chord will fit into our C major scale as all 3 notes fit perfectly into our scale. The scale is C D E F G A B C, and in the F Major chord you have an F, A & C. Perfect! Therefore the fourth chord of our key is F major.

The 5th Degree

We now want to move to the fifth degree of the major scale, which in this case is G. We need to now write down the G major scale so that we can work out the three triad chords. They look like this:

So we can clearly see that the G major chord will fit into our C major scale as all 3 notes fit perfectly into our scale. The scale is C D E F G A B C, and in the G Major chord, you have a G, B & D. Perfect! Therefore the fifth chord of our key is G major.

The 6th Degree

We now want to move to the sixth degree of the major scale, which in this case is A. We need to now write down the A major scale so that we can work out the three triad chords. They look like this:

So we can clearly see that the A minor chord will fit into our C major scale as all 3 notes fit perfectly into our scale. The scale is C D E F G A B C, and in the A minor chord you have an A, C & E. Perfect! Therefore the sixth chord of our key is A minor.

The 7th Degree

We now want to move to the seventh degree of the major scale, which in this case is B. We need to now write down the B major scale so that we can work out the three triad chords. They look like this:

So we can clearly see that the B diminished chord will fit into our C major scale as all 3 notes fit perfectly into our scale. The scale is C D E F G A B C, and in the B diminished chord, you have a B, D & F. Perfect! Therefore the seventh chord of our key is B diminished.

Key Construction Formula

In the last set of lessons, we spent a lot of time making sure you understand how we get to the formula for key construction. We worked out that the first chord was major, second minor, third minor etc... The great news is that you don't need to do that every time you want to work out a major key. All you need to do is remember the formula which is:

major, minor, minor, major, major, minor, diminished

So here is an example of that in practice using the D major scale and that formula to create the key of D major. Try playing through all of these chords on the guitar and you will hear how they all 'work' together!

The Relative Minor

Today we look at a new concept, which has the potential to confuse at first, so we will take it slowly! The idea behind learning the relative minor is very practical. Very often we spend time learning one or two shapes on the guitar, or even the theory behind the major scale. Learning how to find the relative minor means you can take the exact same scale but start in a different place to create a new scale. This is potentially a more advanced idea and it will come into full use when we cover modal scales but is great to get a handle on now. The theory is simple: Take your major scale, start from the 6th degree and you have your relative minor scale.

As you can see, the best thing about this is that all the chords stay the same as well! Suddenly, we have worked out the C major key and A minor key, without doing any extra work at all! Every single major key has a relative minor, so this theory can be applied to any of the keys.

Relative Minor Example

We asked you last time to find out what the relative minor of D major was, did you manage it? Well, the answer is B minor. The diagram below should help you understand it a little more:

In Practice

We can practise the above key on the guitar by playing through the chords in D major first, then in B minor. Even though they are the same set of chords, starting and ending on the relative major or minor makes a big difference. In the fretboard diagrams, you can find all the chords of that key in the recommended positions on the fretboard. Try playing them all from D to D, then from Bm to Bm.

Relative Minor On The Guitar

Let's make the relative minor theory easy to use on the guitar. Firstly, the relative minor is always only 3 frets away from the major. So if you take the C note (assuming you are in C major) and drop down three frets you get the A note, which tells us that A is the relative minor. It works with every key. It also works in reverse, so if you had G minor key and wanted to know the relative major, you just climb up 3 frets to get Bb. Take a look at the fretboard diagrams for an example.

Why Do We Need This Info?

Knowing the relative minor is so important as it halves your workload on the guitar. Rather than learning 5 shapes for the major scale and 5 for the minor scale, you just learn the major ones and learn how to apply them to the relative minor. Equally, with chords, you can simply learn the chords within the major key and quickly apply it to the relative minor.

In the fretboard diagrams section, we have the root note major chords (A) and the two other major chords (D and E). This gives us a solid major sound. When we move down three frets from the root chord (A), we get F# Minor and then can find the 2 other minor chords (Bm and C#m), thus putting us into the relative minor key and making more of a minor sound. Try it for yourself and have a listen.

Conclusion

In this final video, we recap everything we have learnt up to this point and try to make it all nice and clear for you! There are a lot of similar bits of theory and sometimes the trickiest part is seeing how they all work together. So, if you still don't understand some of the theory after watching this conclusion video then it's very worth going back over those sections a few more times until it sinks in! Have fun!