Chord Voicing and Inversion

In our last composition post, I outlined why I think it’s important for a producer to have a strong grasp of composing and arranging. Today I want to talk about a technique that I like to use for building keyboard parts, splitting chords between two hard-panned guitars and creating harmonic depth. This can be accomplished by changing a chord’s voicing and making use of chord inversions. Before we dive right in with examples, we will need to discuss a few concepts and introduce some basic musical terminology. For our purposes we will keep the prerequisite music theory as simple as possible; we will only define the concepts and terms that are required to understand the examples contained in our post. In the coming weeks, we may expand on this theory framework but we will always try to approach it in a way that is useful to contemporary musicians without worrying too much about the classical terminology.

In its simplest form, a chord can be described as three notes played together. This type of simple chord is referred to in the western, classical tradition as a triad. The triad comes in 2 basic tonalities: major and minor (for now we will exclude diminished and augmented). A basic triad is comprised of the 1st (root), 3rd and 5th notes of a musical scale (eg. do-re-mi-fa-so-la-ti-do from the major scale). Almost any chord you might decide to play in a progression can be defined as either major or minor and can also be approximated by a triad. Although you may not be playing the triad directly, if you are able to infer by ear whether a chord is major or minor, the triad can be played in place of the original chord (more on this later). Here’s how you would construct a major and minor triad on a guitar or keyboard:

FIG_1

Note that the triads are identical save for the position of the 3rd which is shifted down one semitone (fret) for the minor version of the chord.

The fact that I have chosen to show the “C” triads is unimportant (don’t worry about the note names). What is important is the interval distance between the root (1st note), 3rd (major or minor) and 5th (perfect) which are arranged in the same fashion regardless of the note names. Additionally, the fifth is called “perfect” because it is neither major nor minor when played with the root. It is the placement of the 3rd between the root and the 5th that gives the chord its tonality. If the 3rd is major with respect to the root, we would need to stack a minor 3rd on top of it to get to the 5th and complete the triad. The opposite is true with a minor triad – the distance between the root and 3rd is a three semitones and the distance between the 3rd and the 5th is a is four semitones. In fretboard terms, you can think of these relationships more mathematically. If the root is at “0” or the open position, then the minor 3rd is at the 3rd fret, the major 3rd is at the 4th fret and the perfect 5th is at the 7th fret:

In the image above, consider playing these notes in sequence on the low E string of a guitar. When a chord is played one note at a time in sequence, it is called an arpeggio. These two sequences would constitute an E minor and E major arpeggio respectively.

In the image above, consider playing these notes in sequence on the low E string of a guitar. When a chord is played one note at a time in sequence, it is called an arpeggio. These two triad sequences would constitute an E minor and E major arpeggio respectively. The only difference is moving from the 3rd fret to the 4th fret (or G to G#).

One of the most useful facts about the triad is that it can be rearranged. As long as the original three notes are used, they can be multiplied in any octave and any order without changing the chord. In classical terms, these rearrangements are called chord voicings or inversions. For instance, a power chord (the common rock guitar chord shown in the figure below) is really just a voicing of the basic triad chord, excluding the 3rd and adding the octave. The fact that the third has been stripped out simply means that the tonality is more ambiguous when the power chord is played on its own. It also makes the chord very easy to play on a guitar since you don’t have to worry about changing the chord shape to reflect this tonality as you move around the fretboard.

Let’s consider the example below and play around with a power chord by adding some other notes from our triad. What would happen if we added the minor 3rd above the octave and/or the 5th below the root? As long as the original three notes of the triad are respected, we can add or remove as many notes as we wish. We will still end up with the same chord in the strict sense but it will have a new flavour.

The original notes of the power chord are highlighted in red. The added notes are in blue. The C power chord can be considered a voicing of a C triad because the lowest note is still the root (C), however in our case, because our lowest note is the 5th of the triad (G), this is technically a chord inversion. The difference is more academic than practical – the important thing is that we can arrange the notes of the triad in any sequence.

Hopefully you’re starting to see the bigger picture now and can recognize how this concept might assist you in building more elaborate compositions from a simple starting point. Certainly you could use your ears to find all the correct notes across multiple registers and instruments but with a little practice, you’ll be able to use your knowledge of triads to quickly fill out a piece of music and feel confident that each note is in the right place.

Suppose you had two hard-panned, heavy guitars in Drop-D each playing the same power chord progression. How would you change one guitar part to sound different but still respect the overarching chord progression of the song? Let’s use the following common chord progression as an example displayed in guitar tab and on a master piano roll:

See if you can come up with chords for the second guitar to play by picking notes from the triad. Remember we are tuned to Drop-D for this example.

You will notice that there is some space between the lowest note played by the first guitar and that of the bass. Let’s add a second guitar part in an attempt to fill in some of these notes based on the triad notes of each chord. We will have some overlap between the two guitar parts, but there will be enough difference to create better separation and a more harmonic breadth.

Notice that the right guitar part plays some of the same notes as the left and bass guitars, but it also fills in some new notes that belong to the triad.

Notice that the right guitar part plays some of the same notes as the left and bass guitars, but it also fills in some new notes that belong to the triad.

Now let’s add a nice keyboard pad above the highest guitar notes. Naturally we could play the same original power chords transposed up an octave or two, however let’s try to keep the chords as close to one another as possible both for playability by a real keyboardist and audience listenability. The listener’s ear will naturally be drawn to the highest note played in the chord. If these notes are jumping around too much the chord progression can sound a bit disjointed or even distracting when played alongside a melody in a lower register. (NOTE: for the purpose of more easily relating the keyboard chords to the guitar chords, the tab figure below is shown down an octave from the piano roll and recording)

At this point we have covered almost 5 octaves worth of notes to create massive chords that are all harmonically correct and will sit well in a mix without sounding too cluttered or muddy. This is how a symphony orchestra manages to use many instrument sections at the same to produce a thick rich sound whilst maintaining a strong and coherent melody.

Notice that the keyboard notes are all withing a few keys of one another because we have selected the a voicing that is physically nearest to the previous chord. Also, the top and bottom notes of each keyboard chord are one octave apart. This is what you would expect if only triad notes are used and none are skipped.

Last, let’s listen to how these changes are reflected in a simple virtual instrument recording. First you will hear the left guitar part played by itself. Then you will hear the right guitar playing the same chords, but using different voicings. Then both guitars will play together, followed by the addition of the bass guitar and finally a keyboard pad in a higher register:

 

Notice how the use of chord voicing and inversion allow us to build a harmonic structure across multiple registers but preserve the original chord progression! At this point we have covered almost 5 octaves worth of notes to create massive chords that are all harmonically correct and will sit well in a mix without sounding too cluttered or muddy.

In our next post, we will dive deeper into constructing chords and analyze a famous Hollywood film score that you can you use to practice your voicing and inverting skills!

Here are a few questions that you might have wondered about as you read through this post. Try answering them yourself:

  • How do I know whether a chord should be major or minor in a progression?
  • Where do the 2nd, 4th, 6th and 7th notes of a musical scale fit into chord construction?
  • Do melody and harmony need to respect the notes of a triad?