The final chapter in the Music Theory for Guitar series shows how to build chords. As you now know how major and minor scales are formed, it’s time to learn how to construct basic and complex chords. It’s all about numbers and letters! If you can say the alphabet from A to G, and you can count to fifteen, you’re already half way there! That sounds way understated, doesn’t it? Well, it’s really not . . .
When three or more notes are sounded together, they comprise a chord. Two notes played simultaneously don’t qualify since they’re considered intervals. Basic chord construction for guitar begins with a triad – a three-note chord that must contain the first, third, and fifth degrees of the major scale. Although the tonic must remain constant, the other two notes can be altered to change the character, or sound, of the triad.
As you will see in the following examples, based on a C major scale, the triads and more complex chords are built by stacking notes in intervals of a third – line, line, line or space, space, space. Remember that a major third is always a distance of four half steps; a minor third is always a distance of three half steps. This is the most common type of chord construction, and is termed tertian harmony.
There are four types of triads, all of which exhibit distinctive sound quality and function. Major triads always contain the Tonic, MA3, and P5 (C, E, and G); minor triads contain the Tonic, mi3 (lowered a half step), and a P5 (C, Eb, and G). Again, major chords sound happy, while minor chords sound sad. But, regardless of mood, both have a pleasant and satisfying quality and are considered consonant.
Conversely, augmented triads and diminished triads have a very distinct, unstable and harsh sound, and are considered dissonant. Both of these triad types for guitar seem to be screaming, “Don’t leave me hanging . . . go somewhere . . . go somewhere!” And, they always do – to a consonant chord. So, they’re used primarily as transitional chords to enhance melodic or harmonic movement. To make an augmented triad, simply raise the fifth of a major triad (C, E, and G#). To make a diminished triad, lower the fifth of a minor triad (C, Eb, and Gb). As you know, by definition, the word augment means “to increase” and diminish means “to lessen”. Here’s what the four triads look like on the staff:
Is music theory for guitar starting to make sense? Do you see how important it is to learn the major scales? At least, in keys you’re likely to play in? Excellent! Let’s continue with the somewhat harder stuff . . .
Again using tertian harmony, adding more notes to the basic triad provides richness and texture to the chord, thereby allowing more interesting harmonic development. Adding only the seventh note of the scale results in a seventh chord, of which there are also four types. The formula for building a major seventh chord combines the Tonic, MA3, P5, and MA7 of a major scale (C, E, G, and B). A minor seventh chord includes the Tonic, mi3 (lowered 3rd), P5, and mi7 (lowered 7th) – C, Eb, G, and Bb.
Dominant seventh chords combine the Tonic, MA3, P5, and a mi7. Although not unpleasant sounding (depending on your viewpoint), these chords are also considered dissonant and must resolve and move to a sense of consonant finality. Without a doubt, the strongest sound in Western Civilization music is the resolution of a dominant chord back to a chord built on the tonic of the key – major or minor. This type of chord warrants further discussion, so let’s leave that for a later lesson.
The remaining type of seventh chord is the diminished seventh. Like the diminished triad, this chord is usually used to connect other chords. It’s formed by adding a doubly flatted 7th (lowered a whole step) to a diminished triad – C, Eb, Gb, and Bbb. If you were to play this chord, per the example below, on the piano (easier to visualize), you might ask, “Why can’t I call the upper note an A? It looks like an A and sounds like an A. Why isn’t it an A?” Good question! And, it adds some fun to understanding music theory for guitar!
Remember that all seventh chords must include the first, third, fifth, and seventh notes of the scale. A is the sixth note of the scale, so that won’t work! It’s all about numbers! The A versus the Bbb is a great example of enharmonic tones – notes that sound the same but which are spelled differently.
So, what are extended chords and altered chords for guitar? By extending the scale into the next octave and adding the ninth, eleventh, or thirteenth note, the chord becomes extended. These chords presume a full seventh chord as the basic unit. If any of the notes are changed from their diatonic position in the scale, the formation becomes an extended altered chord.
You’ve probably looked through a song book and encountered chord symbols that you don’t recognize. For example, if the suggested accompaniment chord is a C13b9#5, a G7/6, or a G/B, you’ll probably wonder what the heck that means. But, the beauty of chord symbols is that they give you specific instructions regarding how to construct the chord. It tells you exactly which notes should be included.
Let’s look at the three examples mentioned above. The C13b9#5 tells you to start with a C7 chord, add an A, add a Db, and lower the G to Gb. The G7/6 instructs to you to add an E (the sixth note of a G major scale) to a G7 chord. The G/B indicates that when playing a G chord, a B (already part of the chord) should be the lowest note. It’s like a roadmap! That’s really not too hard, huh?
One more thing – major and minor chords are clearly noted as such – Cmaj7, CM7, Cmi7, Cm7, etc; dominant chords are noted as C7, C7#5, C9, C13b9, etc.
And finally, the notes of any chord can be stacked in differing order, resulting in a chord inversion. If the root (tonic or keynote) is the lowest note of the chord, it’s in root position; if the third is the lowest note, it’s a first inversion. If the fifth is on the bottom, it becomes a second inversion; and, lastly, if the seventh is on the bottom, it’s a third inversion chord. That’s it – there are no other ones, luckily!
The topics covered in this series of lessons represent only an overview of music theory for guitar. All of the material can be subdivided into equally interesting and relevant topics, and I encourage you to explore many more. However, understanding fundamental scale and chord construction for the guitar is the first and most important step in elevating all aspects of your musicianship. Your technique will improve, as will your creativity.
Doesn’t it feel good to know how music theory for guitar really works? We covered a lot of important topics in these three lessons, and granted, it takes some time to figure out how everything fits together. Instead of just sitting down to play the guitar, think about which chords and notes you’re playing. Music theory for guitar is as fun as you make it -- so make it fun! Because it is!
Music Theory for Guitar (part 1) - Major Scales
Music Theory for Guitar (part 2) - Minor Scales