To be able to harmonize a melody you first need to have a melody and/or know how to make one. The next piece of knowledge you must have is about chord formation; and finally, the experience of how each chord sounds and feels to you. The more you are comfortable about these three aspects of music, the more informed and varied are choices you will be able to make.

One thing that you have to keep in mind, and be aware of is that when a chord is struck, and you have a melody going on over it, in that moment you will get an overall harmonic impression. On the other hand, while the melody proceeds, the harmonic choice you made will provide identity or character to the melody. Obviously, in both cases, this is a two way street because one helps to provide musical context to the other – the interaction between the melodic pitches and the chord.

And with that said, let’s get started!

1. Generally, when choosing chords to harmonize a melody, these usually fall on strong beats – i.e. the first and/or third beat. The first way we will look at how to harmonize a melody is to match the notes in the melody with the notes of the chord we choose. The melody will remain the same throughout the examples:

Represented in color, you can see the matching melody and chord pitches

This way of harmonizing a melody, while effective for certain musical contexts, can sound a bit redundant because the pitches used in the melody are already contained in the chord formation we have used. I think it goes without saying, but it is good to keep in mind the guidelines about voice leading practices as it helps to make smoother chord transitions.

2. Considering the above, the next suggestion is to harmonize the melody in a way that the melodic pitches are perceived in the overall harmonic context as chord extensions, meaning that we will be aiming at how that specific melodic pitch would sound with that chord as a ninth, seven, sixth or other interval when that chord is struck:

3. Another way we will be looking into this technique, as we increase complexity, is to create a countermelody in the form of a bass line. This will help to keep you on track and narrow down some of the chord possibilities. As soon as you write down a bass line, its interaction with the melody may already start to suggest the harmony. This bass line may also be used to inform you about the harmonic rhythm – as in the amount of chords you are going to use:

The harmonized bass line and melody

4. Although it is not mandatory, at all, try to aim at consonant interval relationships between bass and melody. But you don’t have to follow suggested harmony by bass and melody and instead try to use chord inversions other than the first or second inversion, which are more common. One way to look at it is to think of the chord to be more related to the melody than to the bass line. This may yield pleasurable and unexpected results, or not. Just experiment with it:

Using the same bass line but harmonized with different chords

5. Thus far, we have been using chords from same tonality but, as long as the chords contain the melody they pertain to, we can use chords from different tonalities, as well. The approach is the same as before, either with or without the creation of a bass line. If you feel overwhelmed because of the myriad of possibilities, you can choose beforehand the tonalities that you are going to be working with. The following example will be using chords and bass line from C major and Eb major tonalities:

You don’t have to impose any type of constraint regarding the provenance of the chords you are working with and instead, rely on your instinct and knowledge of how each type of chord sounds, with the implied melody.

6. We have been working with a melody that stayed in the same key, but you can also adapt it to the chords you are using. Nevertheless, this means that you will be modulating between C major and Eb major, but how knows if this isn’t the twist you are looking for:

Finally, in the process of harmonizing a melody, you can make the decision of using a specific type of chord formation, like chords in fourths, seconds, polychords, clusters, or other process of making chords like mirroring chords or chords obtained by any serialization process. These would just be another type of constraints but ones you can definitely experiment with using many of the principles I approached here. Now it’s time to have fun and come up with your own melody harmonizations.

Happy composing!