The Only Theory Lesson You’ll Ever Need – Part 3

In Part 1 of The Only Theory Lesson You’ll Ever Need, we covered the foundational elements of music theory: the musical alphabet, the concept of whole steps and half steps, and the use of accidentals (sharps and flats) to fill in the blanks between natural notes.

In Part 2, we used that information to take the next step forward: constructing major scales and understanding keys.

Here in Part 3, we’ll take the final step and use our knowledge of major scales to harmonize them with chords.

This is where music theory really starts to come alive because it gives the musician insight into why certain chords work together to form complementary sounds. You can use this knowledge to empower you to learn songs by ear or to write your own songs. You can also use this knowledge for transposing to other keys, which is essential when applying capo strategies. Rock and roll!

Happy Together

Understanding major scale construction is critical to your understanding of all music theory, but by itself, it’s not very exciting. However, harmonizing the major scale – otherwise known as, “building chords” – is much more exciting, because it clues us into what chords are in what keys, and why they sound good in certain combinations.

This is a major hurdle to get over for anyone who wants to write their own songs! It’s also incredibly helpful when learning any music by ear (be sure to check out my post, The Lost Art of Learning By Ear, as well as any of the Guitar Noise series on Ear Training, beginning with Happy New Ear, for more on this awesome topic), and that could mean learning a song from your iPod or just hanging with other musicians in an informal jam session.

Here’s the scenario: You love your classic rock and so you’re learning the Bob Dylan song, “Like a Rolling Stone.” You see from your trusty music book that it seems to have no sharps or flats, which would indicate to you that we’re playing in the key of C. But how do the chords of the song – C, Dm, Em, F, G, etc. – relate to this? Why these chords and not some others? How did our boy Bob know what chords would sound good together?

Never fear, Grasshopper. Learning to harmonize the scale will reveal the answers!

Stacking Thirds

Take another look at our C scale: C-D-E-F-G-A-B-C.

Now let’s follow a process called “stacking thirds” to build a three-note chord, or triad, from each note of the scale.

To “stack thirds”, we’ll just pick a starting note, leap-frog over the next note to land on our next target note, and again leap-frog over the next note to land on our final target note. This gives us the three notes of our triad, and we “stack” these note, figuratively-speaking, on top of each other.

C…leap-frog over D to land on E…leap-frog over F to land on G.

Our C chord, then, is comprised of the starting note plus the two targets: C-E-G.

Quick Music Lingo Note: “Stacking thirds” refers to two different concepts. We “stack” them, by figuratively sitting the higher notes of the scale on top of the lower notes. So in our C chord, C would be the lowest note, E would sit on top of it, and G would be the highest note.

“Thirds” refers to the span of three notes. Counting from C (as “1”³) to E (as “3”³) encompasses three notes: C, D and E. Likewise, E (“3″³) to G (as “5”³) also encompasses three notes: E, F and G. Taken together, every triad is regarded as having a root note (“1″³), a 3rd and a 5th.

If you want even more information on this, check out Guitar Noise’s article, The Power of Three.

Using the leap-frog method of “stacking thirds”, we can finish harmonizing the C scale by building triads on each of the scale tones:

D yields…D-F-A
E yields…E-G-B
F yields…F-A-C
G yields…G-B-D
A yields…A-C-E
B yields…B-D-F

Done. Now what does it all mean?

Let’s Get Diatonic

Without going into why the following information is true (we can save that for a future theory lesson), suffice it to say that the triads you just built from the major scale yield the following chord names (items in the list are shown as SCALE DEGREE = ROOT NOTE = TRIAD NAME):

1 = C = C major
2 = D = D minor
3 = E = E minor
4 = F = F major
5 = G = G major
6 = A = A minor
7 = B = B diminished

These chords are the diatonic harmony in the key of C, meaning they are the triads that naturally occur in the key, using just the notes of the major scale to build them. Because these chords are all constructed from the same family of notes – the pitches of the major scale – they will sound complementary to one another in just about any context.

So if you’re wondering why Bob Dylan chose C, Dm, Em, F and G for “Like a Rolling Stone,” it’s because he knew – either technically or instinctively – that those chords are all from the same family of notes and sound good together (and he’d do the same sort of thing with “I Shall Be Released,” although in a different key!).

This is powerful information for the developing musician/songwriter, because it gives you a guideline to follow for learning or writing songs. For instance, if you were trying to learn a song by ear, rather than use the trial-and-error method, where you just take a stab at whatever random chords you know in hopes of hitting a good one, use the chords that are diatonic to the key as your first choices. Only when you can rule them out, should you look to non-diatonic chords for your answers. This is a much more efficient way to go about your musical business, and ultimately much more professional. It also takes away some of the mystery of song construction and makes you feel more empowered as a musician!

Primary Chords

Now that you know how to harmonize one major scale, guess what? You know how to harmonize all of them!

Because all scales are constructed from the same major scale formula, they all have the same relationships and the same do-re-mi sound. Because they have the same relationships, the chords that we build by “stacking thirds” are always the same type at the same scale degrees! Check it out:

Major scales will always yield MAJOR CHORDS at the 1, 4 and 5 degrees of the scale. These are referred to as the primary major chords in a key. In our above example in the key of C, we get C (1), F (4) and G (5) chords.

Major scales will also always yield MINOR CHORDS at the 2, 3 and 6 positions – which are referred to as the primary minor chords in a key – as well as a lone DIMINISHED CHORD at the 7 spot. In the key of C, we get Dm (2), Em (3) and Am (6), as well as B diminished (7).

Understanding these concepts and committing them to memory takes practice. Since you have already gone through the process of writing out some of the more common major scales in Part 2 of this theory lesson (you have, haven’t you?), you should take it a step further now and harmonize those scales with chords. Go ahead and stack the thirds, and then write out the name of the triad that each scale tone yields. You may be interested to see that the combinations of chords you’ve been playing in your songs are there for a reason!

I’ve prepared a handy-dandy worksheet to help you out:

Harmonizing the Major Scale

Changing Keys

Knowing what chords fall at what scale degrees in a key is the secret to transposing songs from one key to another. It’s as simple as using the scale degrees to help you substitute one chord for another.

For example, you know that every major key has major chords at the 1, 4 and 5 positions in the scale. If the song you’re playing is in the key of C and it consists of the C (1), F (4) and G (5) chords, you can transpose this to any other key by just using the 1, 4 and 5 chords of the new key in the same spots in the song. Simple substitution!

This is not only an important idea to understand in general about music; it’s a critical concept to understand if you want to use a capo effectively, since capoing and transposition usually go hand in hand. Check out The Definitive Lesson: Essential Capo Strategies as well as the Guitar Noise lessons Turning Notes into Stone – A Basic Guide to Transposing and The Underappreciated Art of Using a Capo for a ton of useful information on this topic!

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