In Part 1, I introduced a general rule: the further from root the melody note is, the more sophisticated the sound is going to be.
This is a general rule because it requires a lot of nuance and is not always true. For example, there will be occasions where you get a better sound with a 9th rather than an 11th as the melody note even though the 11th is further away from the root. There are numerous caveats and things to know to really apply this rule well.
In this post, I will give you two of the factors that are really important in regards to this rule.
Does the extended tone (color note) work with the chord?
Remember that there are 12 chromatic tones in an octave. A triad uses 3 of those tones (root, third and fifth). The 7th takes up 2 more of those tones because a 7th can be either major or minor. That leaves 7 other notes (often called color notes) that are available to add to the chord. Here they are:
b9, 9, #9, 11, #11, b13, 13
I know this may be a bit overwhelming but go to a piano and play a C major triad. Then add the 7th (either B or Bb). Hold that position and look at the notes not being played. Those are the 7 notes I just listed. Db is b9, D is 9, D# is #9, etc.
If you are choosing a chord for a melody note, based on my rule, it is a good thing to choose a chord that makes the melody note one of these color notes. In other words, a C chord underneath a D melody note is a good thing.
That being said, it is not quite that simple because each type of chord has a specific subset of the 7 color notes that it works with. Let’s take the example where the melody note is Db. A CMaj7 will not work under that melody note because a major 7th chord does not like the b9 color note. However, C7 will work because dominant chords work quite well with b9 color notes.
I won’t go into all the combinations here. If you want to dig into the subject, get my course on Reharmonization.
Does the chord you choose make “functional” sense?
When you are looking for a chord, you have to consider more than the melody note. You also have to consider the surrounding chords. In other words, you need to think horizontally as well as vertically. The chord you choose needs to make sense in the overall chord progression.
What I am discussing here is the subject of functional harmony, which is essentially the understanding of how chords relate to each other.
Here is a very simple example: the most basic functional harmony rule is that chords like to move (progress) in 5ths going down. In other words, in the key of C, an A chord likes to move to D which then likes to move to G which moves to C. That is movement by fifths. There are many other functional harmony rules though perhaps not as many as you might think.
As a general rule, when I pick a chord, I want to be able to defend its position in the overall progression using functional harmony. Again, if you want to study this more, get Reharmonization.
I am going to close with a real life example. Here is a typical simple harmonization.
There is nothing really wrong with this harmony. Note the use of the vi chord (Fm7) and note that the melody note (Eb) is the 7th of that chord. That is a good sound. The second bar is the weakest bar. The Eb7 is the V chord and the melody note is the root of that chord.
To improve this harmony while following the two rules, we are going to modify that second bar by essentially splitting it in two and substituting a chord for the Eb7 on the first two beats.
Note what has happened. Using Bbm7 moves the melody note from the root all the way to the 11th (Eb is the 11th of the Bbm7 chord). The natural 11th works great on a minor 7th chord so that works fine. In addition, the Bbm7 works great with the chords around it. It is the ii chord which is a fifth below the vi chord in front of it and a fifth above the Eb7 that proceeds it. In other words, the functional harmony rule about moving in fifths is being followed.
The result is a great sound. Try playing both versions of the harmony and you will be astounded at the difference.
I am not going to say this is easy. It really takes some time to learn it and then more time to get it into your fingers so you can do it instinctively. However, there are concrete rules that govern all this. I hope this little example will whet some appetites.