Key Change

In this post I’ll discuss the music theory behind a particular key change. The song “Wrestle the Reticence” is in G major, but at the end, there is a key change into the key of  A major. However, this transition needed to happen naturally and smoothly so the listener isn’t shocked by the change and actually feels as though the change was necessary.

The trumpet leads the key change by bringing the melodic line from the root (G) to the fifth (D) and then to the 2nd of the G major scale, which is A. Going into the key change, the melodic line is sitting on the 2nd degree of the original scale, G major. This naturally wants to resolve down to the first scale degree, or the root, which is G. However instead of bringing the melody back down the scale root, I brought the scale root up to the melody, thus completing the key change and giving the melody a resolved feeling because now the A that is being played is no longer functioning as the 2nd degree of G major, but the root of A major.

Just like in the melody, the bass and the chords have to move underneath the leading trumpet in a natural way to naturally complete the key change. Moving into the key change, the chords go from the major 1 chord (G major) to the major 5 (D major) chord, and then the key change occurs. Moving from the 1 to the 5 chord of a scale has a very clear, predictable leading motion, and this pattern will help whatever chord follows the 5 chord to feel natural. After the D major chord, (the 5 chord of G major) the next chord that lands is A major, signaling the new key of the A major. This transition works particularly well because the interval from G to D is up a 5th (which I mentioned clearly leads the progression) and the interval from the D to A is also up a 5th. These two intervals of 5ths feel very natural in leading this key change.
As far as applying music theory, this key change is a great example of how many necessary concepts come together in a somewhat technical manner to achieve something very conceptually simple. If done correctly, the result feels effortless. It was exciting to see how following certain rules helped produce a sound that felt “right.” Sometimes the je ne sais quoi of why something feels right (or wrong) lies in the theory behind it.