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Harmonizing the Line - Best Practices

Harmonization is a beautiful and decorative technique in music composition. Sometimes, it can be quite elegant to provide some harmonic context to a given melody as the overall result becomes more sophisticated.

Personal Confession: To me (Frank), making harmonization work so that I was happy with the results was always tricky. Out of frustration, I tried to find patterns and concepts that could help me get rid of the guessing. In this article, I'll highlight the best practices that I came across so far so that YOU can skip this frustration-part and get into the application right away!

Harmonization in music refers to the combination of a line/melody with chord tones that all move in the same rhythm. The human ear usually picks up the top line the easiest. That's the lead line. The other voices (below) thicken the lead line vertically, and also provide harmonic context.

Best Practice #1: "Quick and Dirty"

I would almost call this technique the "standard-way" of harmonization as it appears most often in BigBand-writing or Jazz in general. To apply this method, we must know just one thing - and that is the chord progression!

From here, we can remove the guessing 100% and jump directly into the application! So, here's the process.

Simply ask the following question: Is the melody tone you want to harmonize a chord tone? Yes or no!

If it's a chord tone, you want to use other chord tones below it. If not, you want to create a vertical structure that consists of equivalent 3s (3+3+3)!

Before we dive into an example, let's define what equivalent 3s are. Diatonically speaking, they create Secondary Dominants (provided you pick the proper root). However, using interval theory simplifies the process. As we use half-steps (or chromatic steps) to determine the distances between two neighboring notes, you can simply count to three while going down chromatically from your melody tone. That's how you get to the correct sounds.

So, equivalent 3s equal stacked minor thirds in the Diatonic system - quite simple. If your melody tone was the note C, and if that C was not part of the chord structure, here's how it would be harmonized with equivalent 3s.

Going down three half-steps from C brings us to A. Going down three half-steps from A gets us to an F#. And the next note would be an Eb. That is an example of a 3+3+3 - structure.

Musical Demonstration

Here are the first four bars from the well-known song "Happy Birthday To You". The root progression and also the chords are rather simple and clear.

Let's start the process and analyze the melody tones so that we know what tones equal chord tones. Remember: We want to harmonize the chord tones with other chord tones. So, let's write down the root progression and the chords before going any further.

As we will deal with triads quite often but wish to write four-part structures, let your fourth voice go to scale tone six in that case. All the chord-tone structures are labeled in blue, and the equivalent 3s show up in red.

The only thing that rarely sounds good is a repeated vertical structure. Since the melody repeats a note, the technique produces repeated structures in two spots shown in orange.

So, let's use substitute tones (ST) or chromatic alteration (CA) to make each part move a bit more. Usually, this results in better performance and a more exciting line in general. Please have a listen to the "fixed" result below - every part moves smoothly underneath the melody now.

Great. I like that, and you can apply this concept to any line. Just make sure you know the chord progression first. In my opinion, this technique leads to excellent results and is easy to apply.

And here's even a little side-note: It does not only work correctly in close harmony but also sounds excellent in open harmony as well! You might want to drop the second or third voice down by one octave. This creates more space around the top line and usually leads to more transparent arrangements.

Best Practice #2: "Chromatic Lines"

For the second technique, let's bring in one of my most favorite elements of all time - chromatic lines (or simply 1s)! Actually, we are talking about two different cases that we want to explain separately as both have their unique benefits but also challenges. Depending on your knowledge about harmony and chords, you might find the first one to be a bit more advanced.

1s in the Bass - The Root Cycle 1 (RC1)

We've already covered the various root cycles (RCs) and how you can use them in music composition. To highlight the slight nuances to the first technique, let's stick to "Happy Birthday To You" and the basic feel of it throughout the whole article. 

Let's bring in the original chord structures, together with their roots, to strengthen the rest points in the melody. Now, here comes the trick:

Write the chromatic lines in reverse from the rest points and use the same rhythm as found in your melody tones!

Theoretically, you can use ascending or descending lines, but I gravitate towards a descending line into the rest point as I like the sound of it.

Up to now, we followed a simple method, but now, let's talk about the creative part to find the inner voices. Here's what I suggest. Think of every bass note as a mini-tonal center and regard the note in the treble as a chord tone. If you are new to music theory, this step might appear a bit complex, as this can quickly lead to jazzy chords from the second octave - so, some solid knowledge about harmony is required.

But if you feel overwhelmed, I recommend you skip this technique and move on to the next.

I know that this example below looks a bit complex at first view, but analyze one structure after another. You'll see that the inner voices only support the lead line so that we create stable chords over their roots.

And again, open harmony works nicely with this technique, as well. It can even create some beautiful contrary motion between your voices and the root.

1s in the Treble

Here's the second option for chromatic lines. We want to reuse the harmonized rest points, which we created in the above example a minute ago.

Again, we are going to write all (green) lines in reverse into the (blue) rest points. Be sure to try ascending and descending lines because one might sound better than the other, depending on the musical context. And I want you to ignore the bass for now! In case the root tones create a musical problem against the chromatic lines, you can always use substitute tones in the bass if needed.

Note: Sometimes, chromatic lines in the treble are the most natural thing in the world, but there are also moments where they simply don't fit, depending on the context.

I want to mention that the D# against the E in the first bar creates a 13, which is an interval that usually sticks out in the wrong way. Probably, I'd fix that in the final arrangement later, but all the other parts work nicely.

Also, the root tones seem to be okay, but there's one little moment where we hit the dominant flat ninth chord near the end. That structure also creates a 13 (the note F against the E root), but it still works because scale tone -9 (that's the F) gets support from -7 (the D below it). However, if that sound bothers you, look into substitute tones.

Best Practice #3: "Expansion"

The third technique deals with expansion. In the Composition Course, we explain the subject of expansion/contraction in much more detail as it connects to so many beneficial and practical sections in music composition.

Generally, the term expansion refers to going from a smaller vertical structure to a bigger one. We may use scale tones, chromatic steps (with no relation to any scale/root), or even a combination of both.

As stated above, we want to stick to the same melody for demonstration purposes. I like this technique in conjunction with quick-moving melodic fragments as it almost creates little musical explosions that resolve into strong rest points!

Using Scale Steps

Just as above, let's start with the already-harmonized rest points. For a more Diatonic sound, refer to scale-tones only. See how the green structures expand into the blue rest points? That's just movement on the scale.

You might want to adjust some notes to get rid of doubled tones in octaves. As an example of doublings, I've marked two spots below that could need a bit additional attention so that we create a better overall arrangement. However, I'll skip the fix for now so we stay on topic.

With this technique, I'd keep it to close harmony only so that we maintain a reasonable distance to the lead line anyway.

Using Half-Steps

Now let's bring in a bit more spice and color by switching to half-steps or chromatic steps. Keep in mind that this application doesn't line up with the Diatonic approach, as we won't follow any particular scale anymore. The general process, however, hasn't changed at all. We still expand into rest points, but this time, using chromatic steps.

When you compare this result to what we did using scale-steps, you'll recognize a bit of an overlap. Some of the vertical structures appear in both versions, but we've changed the grid from scale tones to chromatic steps.

And actually, the overlap opens up the opportunity to go back and forth fluently between the two approaches! In doing so, you get considerable control over the amount of spice in your arrangement!

Harmonization in Action

Now that we've looked at the various techniques of harmonization, let's have a listen to the full version of "Happy Birthday To You" in the video below.

Members: All Academy members receive an exclusive downloadable handout that brings all techniques together and to the point - almost like a cheat sheet.

(If you are not logged in, it won't work, but I know you'll try anyway!)


As usual, here's a quick list of takeaways for you that make it easy to apply the techniques.

  • Quick & Dirty: Harmonize chord tones with other chord tones and non-chord tones with equivalent 3s.
  • Chromatic lines in the bass: Bring your upper melody tones into the context of chord tones by filling up the missing partials.
  • Chromatic lines in the treble: Move into your harmonized rest points with chromatic steps in all voices.
  • Expansion into rest points: Expansion is a great technique to resolve the tension from small vertical structures into triads. This technique not only works great with scale tones but only chromatic steps.


Harmonization thickens a line, but it can also organize and structure your melody fragments (or strings). You can even create calls and responses out of your existing line by bringing in harmonization only in a small chunk of the line.

Frank Herrlinger

Co-founder and instructor at Music Interval Theory Academy