How To Start Reharmonizing

The year was 2012 and I had just decided to drop out of an engineering degree to pursue music. I really didn’t know anything about what it took to be a professional musician, let alone how to write music, but I had a burning passion that fueled me and it felt like the right thing to do. In order to save up enough money to fulfill my dream of studying music in the USA, my step dad helped me lock down a security guard position at Melbourne airport. While there I was faced with an abundance of down time, standing around during the night shift with nothing better to do than daydream and come up with melodies. 

Eventually those melodic ideas turned into my first composition, well at least the main melody. You see, even though I had been playing bass in jazz settings for a number of years, I had really no idea how to write a chord progression. I understood the basic components of chords and the different qualities such as major and minor, but at the time I didn’t even understand what the word diatonic meant, let alone what diatonic chords were. In the end, I had my friend sit down at the piano and play a few different chords and that’s how I created my first progression.

A little while later, after I had quit the security job and moved to Texas, I took an introductory music theory class where they explained the basics of chords and where they come from. Although it was a steep learning curve, I loved every minute of it and was writing new chord progressions every day. Then one day the class covered basic reharmonization. To me the word was always associated with the best jazz musicians that somehow took a standard progression and then completely changed it. I had no clue how it was possible and it always felt like some kind of alchemy. 

Fortunately, the class uncovered a couple of different techniques which helped me see that reharmonization and substitution aren’t all that difficult even if the final result feels complex. The first technique the class shared is something I now call “functional substitution” and builds off of the concept of functional harmony. For those that aren’t familiar with the concept, the main idea with functional harmony is that all chords in a given key are assigned functions based on how much tension they have. There are three categories: Tonic - resolved, Dominant - tense (wants to resolve), and Pre-Dominant - something in-between that neither feels resolved or tense. 

Tension in the context of a major scale comes from the semitone/half-steps located between the 3rd and 4th degrees, and the 7th and 8th degrees. As the 3rd and 8th feel resolved due to being major chord tones of the home key, any chord which includes the 4th or 7th will naturally feel slightly more tense. As a result, we can assign functions to each of the diatonic chords.

I - Tonic, features the first and third degree of the scale.

ii - Pre-Dominant, features chord tones adjacent to the first and third degrees of the scale. The inclusion of the fourth degree adds some level of instability to the chord.

iii - Tonic, the III chord is a special case as it doesn’t quite feel resolved but doesn’t quite fall into any of the other categories. Many musicians avoid using it for this reason

IV - Pre-Dominant, features chord tones adjacent to the third and fifth degrees of the scale. Although it also includes the first degree, the inclusion of the fourth degree adds instability where the chord doesn’t feel fully resolved.

V - Dominant, features the seventh degree of the scale which is the most tense tone.

vi - Tonic, features the first and third degree of the scale.

vii° - Dominant, features both the seventh and fourth degrees of the scale which create a high level of tension

Getting back to reharmonization, a simple but effective method is that chords with the same function can be substituted for one another. It works because the general path of resolution of a chord progression isn’t affected even if the sound of the chords within the progression can be completely different. For example, in the key of C major you can substitute any Cmaj chord with Amin resulting in a much darker sound to the progression. As with all sorts of reharmonization, you should make sure to keep the melody in mind because sometimes it may not work with the new chosen chord.

There are a number of other ways to reharmonize chords too, but for the sake of keeping this newsletter from turning into a book, I’ll touch on those at a later time. Thanks for reading this month's newsletter and I look forward to sharing more reharmonization techniques over the rest of March. It might be one of my favorite aspects of arranging and I’m excited to touch on a few of the methods I regularly use.

Thanks,

Toshi