The love of music is a wonderful thing: organic, natural and ancient. Not only has it been an area of human focus for as long as there have been humans, it abounds and springs to life in nature. Sound waves follow patterns inherent in the creation of the universe and can lead us to emotional conclusions that we need to be shown if we can open ourselves up to it. It is there for you if you are willing to listen and will help fill that hole in your soul.
The most powerful and most used progression in music is dropping a 5th in the root. Anyone has merely to play a Dominant chord of a key followed by the 1st chord or Tonic of that key to understand why the monks of Europe in the Dark Ages named the 5th chord of a key Dominant. It is an inherent rule of music that the Dominant chord leads to the Tonic. Anyone can hear the settling of the tone center when this particular chord change is played.
For this particular example of chord substitution I’m going to use an E7 going to an A7 resolving to a Dmaj7. The A7 chord in this progression is going to be substituted by an Eb7 chord which is the same chord type an augmented 4th away in the root. You can hear in the example that this is a pleasing similar sound. I don’t know why this works but it does. It also happens that the 3rd’s and 7th’s of the A7 and the Eb7 are the same notes reversed in position, making the different chords quite alike. What you can realized out of this harmonic device is a chromatically descending chord progression that is different from the cycle of 5th’s with the same amount of solidity and power. When using this device you must adjust the chords to reflect the notes of the melody that are happening when the chord substitution is being played.
There is so much to think about when discussing chord progressions it boggles the mind.
A good starting point in understanding chord progressions is the flow inherent in most any musical piece. Fast or slow, happy or sad, poignant or ludicrous, rebellious or patriotic each tune is built around defining the flow of the piece reflected in style, tempo, rhythmic and harmonic structure.
There are two basic overall rhythmic flow types in music: vertical and horizontal. A good example of vertical music would be a John Philips Sousa march where the rhythm is defined by micro stops in time enforced by emphasis. A good example of horizontal music would be a Bill Evans ballad that magically floats thru time and space. Most tunes are somewhere in between.
Musical compositions are based on establishing a tonal center, going away from it, coming back to it. How you do this is dictated by the style of music and the level of the composer/arranger. There are 3 basic types of harmonic chordal progression: diatonic scale motion (Cmaj7, Dm7, Em7, Fmaj7,etc.), cycle of fifthing (C7,F7, Bb7, Eb7, etc.) and going from relative major to relative minor (Cmaj7 – Am7). You must remember that these progression types have been noted in a simplified manner. The amount of sophistication, creativity and inventiveness that can be applied is endless. The goal of jazz progressions is to proceed fluidly forward with no effort.