What is it about music theory that has the power to inspire boredom, hatred or even fear in musicians? Humans usually don’t care for what they don’t understand, so it makes sense that even the most seasoned musicians sometimes yawn or shudder at the thought of music theory, a topic that’s benefits are frequently undersold and basic concepts poorly explained. But learning just a few music theory concepts is a powerful tool that every musician can use for writing, performing and understanding music. Rather than being a dusty set of rules that you’ll never apply to anything in your daily life, music theory is brimming with living ideas that can completely change the way you hear and create music.
This is part one of a special ReverbNation basic music theory guide. By the end of this guide, you’ll have everything you need to understand intervals, scales, chords, the circle of 5ths and other important music theory ideas. But before I walk you through the basic principles found in music theory, I need to tell you why it’s such an important thing for musicians to become familiar with.
Why music theory should matter to musicians
I’m pretty into music theory. So much so in fact that it’s pretty much all I talked about at a recent party I went to—yeah, I’m “that guy” now, apparently. “I hear you’re a music teacher or something,” a guy said to me. “Do you know anything about music theory? I hated it as a kid.” I smiled and set down my drink.
I don’t blame anyone for having a grudge against music theory. Some people are first exposed to it in public school, a place where educators usually aren’t given enough time, money and resources to properly teach in-depth topics to a crowded classroom of kids. Others got pieces of the puzzle from the private music lessons they took as a child, but nothing close to the whole picture. Yes, learning how to play scales is important, but many guitar and piano teachers don’t bother to explain the hugely important music theory context behind them.
Music theory has the power to lift the veil when it comes to seeing how chords, scales, and key signatures work. Taking some time to memorize just a few simple formulas can give a musician access to a basic understanding why everything in music operates the way it does. It’s more of a language than a theory, and the ideas that govern music are set in stone and never change.
Using a keyboard as a visual guide
To get the most out of this guide, I recommend using a keyboard as a visual guide. The keyboard is basically a perfect visual representation of what’s happening in music theory. This means that pianists have it pretty easy when it comes to mastering the basics of music theory. Musicians who play other instruments can easily apply the ideas I’ll discuss in this guide to their own instrument. If you can afford it, consider purchasing an inexpensive midi keyboard.
If you want to understand something, you usually have to zoom in as far as you can go to see how it works. This is exactly what we’re going to do with music theory. Before we tackle things like chords, scales and keys, we have to look at the individual notes found in music. Intervals are the relationships between notes in music, and each interval features its own unique sound. The best way to teach intervals is to provide an example of where it’s found in popular music, so that’s what I’ll do here.
I’ll use the note of C as a reference point from here on out to make things easy, but the ideas I’ll introduce here can be adapted to any key. Intervals are measured by the half-steps between notes:
Minor 2nd – C to C# (1 half-step)
A minor 2nd interval is the distance between one note and the half-step above it. Play this interval in the low range over and over again on your instrument and you’ll hear the main theme from the Jaws movie soundtrack.
Major 2nd – C to D (2 half-steps)
The distance between one note and another two half-steps above it is a major second. The first two notes in the “Happy Birthday” song features this interval.
Minor 3rd – C to Eb (3 half-steps)
Minor third intervals are the distance between one note and another one three half-steps above. A minor third interval can be famously heard in the opening melody to the English folk song “Greensleeves.”
Major 3rd – C to E (4 half-steps)
Major thirds cover the span of four half-steps. “When The Saints Go Marching In” features this interval in its opening melody.
Perfect 4th – C to F (5 half-steps)
This interval can be famously heard in the “Wedding March” song that we typically associate with weddings. Perfect fourths are found between one note and another one five half-steps above.
Tritone – C to Gb (6 half-steps)
Tritones feature a dissonant sound and were once officially called “The Devil’s Chord.” Tritones span over six half-steps, and the most famous example of them is found in the opening melody of the theme song from The Simpsons television show.
Perfect 5th – C to G (7 half-steps)
This might be the most important interval in music theory because the relationship between one note or chord and the one a fifth away is one we hear time and time again in music. Perfect fifths span the distance of seven half-steps, and they’re famously heard in the main theme from the Star Wars films.
Minor 6th – C to Ab (8 half-steps)
The distance between one note and another one eight half-steps above is called a minor sixth. This interval can be found in the word “fire” in the song “We Are Young” by the band Fun.
Major 6th – C to A (9 half-steps)
Notes that span over nine half-steps are called major sixths. The most famous example of this interval can be heard in the first two notes of the NBC network theme song.
Minor 7th – C to Bb (10 half-steps)
A minor seventh is the distance between one note and another ten half-steps above. The musical Westside Story features a minor seventh from the song “Somewhere” during the first two notes of the lyrics “there’s a place for us.”
Major 7th – C to B (11 half-steps)
Notes spanning over 11 half-steps are called major 7th intervals. One can be heard in the song “Pure imagination” from Willy Wonka and The Chocolate Factory during the lyrics “a world.”
Octave – C to C (12 half-steps)
Finally, we’ve reached the interval of an octave. Octaves span from one note to another note of the same name 12 half-steps above. This can be a confusing concept at first, but there are many different notes in music that share the same names. I could go into the science behind why (it’s called the overtone series, and it’s actually pretty interesting), but let’s save that for another article. An octave is found in the opening melody to “Somewhere Over The Rainbow” from The Wizard of Oz.
You don’t need to memorize all these intervals right away, but they’re a crucial part of other concepts in music theory.
Chords are different combinations of intervals that are played simultaneously. There’s three basic types of chords in music: major, minor and diminished. Adding notes to these basic chords changes the sound of them completely, but for the purposes of this guide we’ll just stick to your garden variety chords for now. Unless you’re into some truly obscure stuff, pretty much all the music you listen to is built off over different chord progressions. Everything from Beethoven to Beach House to jingles written for commercials selling toothpaste is music built off of different chord combinations.
Here’s a simple guide to teach you how to construct basic chords. The “R” means the “root” of the chord, and to make things easy, the root will always be the C note.
R + Major 3rd (4 half-steps) + Perfect 5th (7 half-steps)
To build a C major chord, you’ll play C, the note of E four half-steps above it and then G, which is seven half steps above C. If you’ve got a keyboard handy, try playing this combination of intervals at different spots to practice building different major chords.
If you play guitar, you might be saying something right now like, “Hey, the C major chord I know how to play has like, five notes in it! What gives, ya big nerd?,” but all basic chords like the C major one I just showed you can have repeating notes. However, basic chords can completely change if a note other than the root of the chord is played on the bottom. These are called chord inversions, but you don’t need to worry about that for now.
Major chords feature a full and complete sound. Many people describe them as sounding “happy,” but I think it’s unwise to stereotype all major chords that way. Context is king when it comes to describing the sound of something.
R + Minor 3rd (3 half-steps) + Perfect 5th (7 half-steps)
If you’ve got a good grasp on how to build major chords, then minor chords should be a breeze for you. They’re exactly like major chords except that the third of the chord is lowered half a step. A C major chord has the notes C, E and G, but in a C minor chord the E becomes an Eb.
This leads me to a very important point. All basic chords are built off of what we like to call triads in music. Triads are sets of three notes that skip alternating notes. So a C minor chord will always have some sort of C, E and G and never a note like a D# even though it shares the same note as Eb. I know this seems super confusing, but it’s actually a system to make understanding notes easier. C-Eb-G is easier to read than C-D#-G on the staff for musicians.
Minor chords usually sound “sad” to most people, but there’s many examples of music that written in minor keys that ‘s able to convey a wide variety of emotions.
R + Minor 3rd (3 half-steps) + Tritone (6 half-steps)
Diminished chords sound tense, dissonant and uncertain. The dramatic music played in silent movies where a villain ties a helpless girl to the train tracks is heavy on diminished chords. Where minor and major chords can be used for countless purposes in music, diminished chords are almost alway used to convey tension, anger, hopelessness and drama.
Diminished chords are built just like minor chords but with the fifth of the chord lowered down a half-step. A C diminished chord is built using the notes C, Eb and Gb. And remember, any C chord has to have some kind of C, E and G in it, so the Gb in a C diminished chord is never going to be called F#.
For practice, I recommend writing down and playing the intervals and basic chords I taught you on your own instrument. If you play an instrument that only plays one pitch at a time, try arpeggiating some basic chords (arpeggiating a chord means to play it note by note). Solidifying the concepts I introduced here are key to understanding everything else we’ll cover in the next guide, so take some time to memorize intervals and how to construct basic chords.
I hope part one of this basic music theory guide has been helpful to you. In the second part of this guide, we’ll learn how to understand scales, discover how to build every key in music with the circle of fifths and I’ll talk about how to construct and understand chord progressions with Roman numeral analysis. We’re just getting started!
Patrick McGuire is a musician, writer, and educator currently residing in the great city of Philadelphia. He creates music under the name Straight White Teeth, and has a great affinity for dogs and putting his hands in his pockets.