We now have an understanding of how chords naturally combine using the I IV V rule. However, we are not saying the chord progression of the song will always be in this order.
The song could possibly start from the I chord or variations of the I chord for several measures then change to the V chord or variations for several measures, then to a IV chord or variations, then back to the V chord, then resolve to the I chord.
The composer may even throw in a III chord, or the iii chord (lower case means minor), or a vi chord. It’s the song writer’s choice. They decide the chord arrangement when composing the song. The I IV V Rule is for determining the Key and the possible chord variations that may come up within the arrangement.
How does this all tie in with Joe and the band?
Every song must have a starting point and an ending point. Have you ever tried singing a song you liked while listening to your iPod but you can’t quite seem to find the range of the performer’s voice? In fact, you try but all you do is sing a bunch of sour notes, very unpleasant to the ear. You are what we call off KEY. Simply put, you have not started at the same place or range/pitch or KEY as the performer.
When a songwriter composes a song to music they usually find the KEY or range of notes that come naturally to them. Everyone has a different voice range. Their starting point or natural KEY may not be the same as yours. Your natural KEY might be the KEY of E or it might be the KEY of D and… so on. In Joe’s case, the singer’s voice range for “such and such” was in the Key of G and Joe was only taught to play the song starting from C. So the question is…How do we solve his problem?
It is called transposing, the ability to change music or in this case chords from one key to another. This may sound complex but in reality it is a very simple process. One of the unique things about music is,, music is predictable and consistent. Music is numbers.
Playing By The Rules uses this same predicable approach for instruction.
The illustration to the right is an excellent example of what I mean by predicable and consistent. It is called the Circle of 4ths and 5ths. It is a very useful tool that also displays a large amount of information at a glance.
More on the Circle of 5ths here.