In this episode we discuss theory in a bit more detail, including information on diatonic chords, cadences and soloing within a key. Don't worry, there is nothing scary here!
The boys kick off with some basics, leading up to building a diatonic key. The first thing we need is to take our major scale. 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 on 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. Here is the formula you can apply to any major scale:
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!
When we see guitar players jamming, there is an understanding of theory taking place. The person playing the chords understands the theory above. The lead player knows that, because the chords are all diatonic, and built from the scale, they can simply use those scale notes to solo with. In the example Thomas and Andy use, they are playing a C major to F major and using the C major scale over the top (shown below).