How can I find simple guitar chords to fit a melody line?

Question

I worked out that the melody line to "Joy to the world" is basically just up and down the D major scale. In fact the first line "joy to the world, the lord is come" is literally the descending melody D, C#, B-A, G, F#, E, D.

It feels like finding guitar chords would be trivial as I know the key and melody but every time I try to work it out based on the notes it sounds wrong. I'm left playing D all the way through!

If I know the key and melody line, how can I safely assign some basic chord changes? Nothing fancy, just a couple of chords per line highlighting the key notes.

Answer 1

I think I know the trap you have fallen into.

In the score below I circled the first note of each measure in green.

Those four notes map out the D major chord. Naturally you might play D major for each bar. If you are using basic guitar chord, those D chords will be in root position.

However, in the classical style of this music the melody ^3 ^2 ^1 - that's the F# E D in measures 3 to 4 - would not be harmonized with chords D | D. Measure 3 needs to be a chord of the dominant or the D chord in 2nd inversion.

If you are not dealing with classical style, @ggcg's answer about I IV V will serve you well!

The rest of what I have written is just detail about this tune could be harmonized.

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A common method for harmonizing a melody will tell you to match melody tones to corresponding chords from the scale. Example, in D major, take the note F#, it is found in the three triads Bm, D, and F#m. One of those chords is a possibility for a harmonization. However, if you do that for all of the tones of a melody, you quickly have a big, jumbled list of possible chords with no sense of how to select from the possibilities. The problem with that is it focuses on a matrix of pitches instead of starting with rhythm and phrasing as the basis for harmonization.

There is a deep connection between harmony, rhythm, and the barline that should be satisfied with a good harmonization.

Before selecting chords assess the rhythm of the music especially the latent harmony of the line. Where does the line pause? Are any chords outlined by the line?

Especially in this style of music phrases end with cadences. If you identify those phrases and select appropriate cadences first, you know where the music needs to go structurally.

Also, we want to think about levels of harmony. The idea is that harmony can be simplified or expanded without loosing the essence of the harmonic functions. Example, a single chord I could be expended to I IV6/4 I. We can use this idea to sort of sketch up from basic harmony to a final harmonization, or to break down an existing harmonization to see its broad organization.

Let's take this existing harmonization and work backwards from the finished product to see the principle applied.

Initially, forget about pitches. Where are the long notes? Measures 2 and 4 get the long notes. Both have a dotted quarter note on beat one. These are our resting points. They should be our harmonic destinations/goals. How about shortest notes? the last notes of measures 1 and 2 are a 16th note and 8th note respectively. Whatever happens on those notes can be considered harmonically subordinate to the main notes. They are details we can gloss over for the moment.

Now let's consider pitches. The first note is D the tonic. Long note, measure 2 is A the dominant. Long note, measure 4 is D the tonic. Also, the end of the phrase - measures 3 to 4 - gives ^3 ^2 ^1 that should leap off the page as a cadential formula.

A general sketch of our pitches so far would fit the rough sketch I |V I which I tried to indicate with brackets at the bottom.

Work backward from the cadence and fill in the detail. Essentially we want to write the cadence and then connect it to the beginning. The melody segment ^3 ^2 ^1 is a common compound cadence formula. Zero creativity is involved, just fill in the formula. (I used parenthesis to show that the I6/4 can be viewed as a V with an appoggiatura above, but it really doesn't matter, it's just a cadential formula.) That takes care of 2 of 4 measures.

The next question is how to treat the melody segment ^1 ^7 ^6 ^5 for measures 1 and 2. The ^5 in bar 2 is the tricky note. It could be part of a tonic chord or a dominant chord. (We will skip over why the mediant chord wouldn't be used.) This is the moment where a mere matrix of melody tones and matching chords will fail us. We aren't simply matching melody to possible chords. We are trying to connect to whatever chord comes next! This is why it was important to find the cadence first. When we know where we are going we can decide how to get there..

The ^5 in measure 2 could be harmonized with a dominant chord, but then it would be setting up a repeat of the dominant chord in measure 3 and that would cause the harmony to become static. Better to use the tonic chord I in measure 2 as a prolongation of the opening tonic chord in bar 1. Now we have gone from a harmonic sketch to the particular harmony for each of our 4 bar phrase I | I | V | I.

The remaining material is harmonically subordinate. Because this material isn't essential we actually have more flexibility with how it could be handled. This harmonization gives us three common devices:

• treat a melody note as a non-chord tone, the ^7 passing tone in measure 1.
• prolong a chord with a pedal 6/4 (or passing chord), the IV6/4 between the two I chords of measures 1 and 2.
• use a pre-dominant chord (chord ii, IV, or vi), the ii6 in measure 2.

Finally the basic method is...

• identify phrases and fill in cadences
• sketch in the primary chords
• fill in the subordinate material

Answer 2

Sounds like you're asking for a couple years of harmony lessons. ;-).

You could just strum the Dmaj chord. Another approach is use the DMaj, GMaj and AMaj chords and pick one that has the note in question in it. These 3 chords (I, IV, V) cover the entire major scale.

There are many rules and regulations w/r to harmonizing a melody in the classical sense, too many to quote here. But the above statement is start.

Answer 3

There is often a myriad of different ways in which to harmonise a melody. The 'most correct' one to a lot of people will be the one they heard most. Only because it's been imprinted into their brains.

One could play a different chord for each melody note. That gets tedious and impractical in a lot of songs. One could water it down to two or three chords. Yes, we've all heard those sort of renditions! But sometimes that's all that's necessary. We could check the (main) notes in each bar, and find an appropriate chord that fits. This exercise comes into every music course at some point at university, I guess.

Basically there's not one 'correct' way to harmonise a song. A lot of jazz proves this statement.

As an exercise, take a simple tune - Happy Birthday, Silent night, for example, and come up with half a dozen different harmonies. Don't gravitate towards 'the original' - except just once - but see (listen) what else works, without changing the tune itself. And, yes, you're probably well aware that you're allowed to use non-diatonic notes in your chords!

As a more specific piece of advice, playing Silent Night in C, there are opportunities for diminished chords, and a nice D9 towards the end - not used as V/V... Very simple starter 'rule' - make the chord tone/s fit the melody.

Answer 4

If you are able (musically experienced) to sing the bassline to a given melody you will easily find the fitting chords and very often you‘ll find several solutions. Start playing „this old house of rocky docky“, joyful, joyful, „silent night“. go by googlesearch: songtitle and "chords", and by practice your analytic ear will get trained. most songs can be accompained with tonica, dominante subdominante, in your case D.G and A7. many songs have a dominante of the dominante (V/V) in the half-end, that means before the repetition of the first line. there are a few patterns of chord progressions to accompain almost all songs: the best way to find the right chords is to get skilled in playing following chord progression using the circle of fifths: I-V-I tonica dominante tonica I-V V-I I-IV-V-I "cadence" I-V-V-I; IV-I-V-I (the mozart scheme) then the well known 12 bar blues scheme and the sub-dominante cadence (jazz cadence) I-I7-IV-IVm-I-V-I (e.g. oh when the saints go marchin' in) most popular: many pop songs have the following cadence I-VIm-IIm-V7 and some variations of this ... with a lot of practice of it you will learn to find out the right chords! concerning joy to the world: this is just very special and difficult .. as it is a barock tune of handel: try to find the right bass line (think of counterpoint) as the melody goes down you try to sing a bass line that goes up and try to accompaigne the scale do re mi fa ... up and down.