Your Friendly Introduction to Music Theory

To define what music theory is, let's first define music and theory:

Music

Music is a series of sounds (pitches) and silences (rests) organized over time.

Theory

Theory is a system that help us think about and analyze something.

Music Theory

So with that, we can see that music theory is nothing more than a system that help us think about and analyze the series of pitches and rests that make up music.

Music theory is not a set of 'rules', but rather a framework that makes it easier to understand how music works.

This framework in turn can become an invaluable tool to help us make music that sounds good to our ears and that evokes the desired emotions.

We defined music as a series of pitches and rests organized over time.

A system of 12 pitches has been created and this system gives us the 12 notes that we now use in Western music. These 12 notes are the basic building blocks of music.

1.1 Musical Alphabet

Out of the 12 notes in our musical system, 7 of them are known as natural notes and each of these natural notes are named after a letter of the alphabet. The 7 natural notes are: A B C D E F G.

Press on any of the note names below to hear the sound of that note on the piano:

1.2 Octave

There are 7 natural notes, but you might say "well there are more than 7 notes on the piano!?" What happens is that after every set of natural notes, the pitch is now double that of the first natural note, and our brain hears that as the same note again but on a higher register.

What that means in practice is that after our set of 7 natural notes, we start again with the same note names on a new 'level' that we call an octave. It's called an octave (octa meaning 8) because of the 7 natural notes plus 1 more note to start again.

Here's a full octave from A to A an octave higher:

Sometimes we want to know exactly which note A we're talking about, not just that's it's one of the A notes. Octaves are numbered, so we can specify exactly which one we're talking about. In the interactive example above, the first A is A3 and the 2nd one is A4.

1.3 Octaves change on C

So far we've been going through the musical alphabet from A to G, but actually we change octave number every time we reach a C note, so it's more common to think of the musical alphabet as starting from C and ending in B, to then start again at C.

Below you can play an octave from C to C and the octave number is included to illustrate the octave change:

1.4 Natural Notes on the piano

On a piano, the natural notes that form the musical alphabet are all the white keys with none of the black keys:

→ Notice how the C notes fall to the left of the set of two black keys.

→ On a full size piano, the note C that's roughly in the middle of the piano keyboard is known as middle C and represents the note C at the 4th octave (C4). Middle C is often a very good point of reference on the piano.

1.5 Sharp and Flat Notes

We talked about the 7 natural notes, but at the beginning of this section I said that there are 12 notes in our musical system. So what are the additional 5 notes then?

The remaining notes to complete our 12-note system have the same note letters, but are said to be either sharp or flat.

Sharp notes are noted with the ♯ symbol and flat notes are noted with the ♭ symbol. So, for example, after the natural note C comes C^♯ or D_♭.

These two note names, C^♯ or D_♭, are two names for the same note, and the name we use to talk about them often depends on context. If we're going up the notes of the piano, we'll often call it C^♯ and if we're going down, we'll often call it D_♭.

Here are the 5 notes that can be either sharp or flat, press to hear their pitch:

The sharp or flat notes are all the black keys on the piano, with none of the white keys:

1.6 Half steps (semitones) and whole steps

We often need to refer to the distance between notes in our 12-note musical system.

In order to do that we need a unit of measure. That unit of measure is called the half step (also known as semitone) or whole step (also known as whole tone). The distance between 2 adjacent notes is one half step, and the distance between 2 notes that have a note in between them is called a whole step.

Calculating distances like that in terms of half steps and whole steps, every note counts, including the sharp or flat notes.

For instance, the distance between C and C^♯ is a half step and the distance between C and D is a whole step.

That was a lot! 😅 Congrats on making it this far. Now that you know about the musical notes, you can start exploring what we do with these notes to create music. 🎉

Now that we know about the 12 musical notes, 7 natural notes and 5 sharp or flat notes, let's talk about how they are used concretely in music.

Just like you wouldn't use every ingredient in your pantry in a single recipe, usually we don't use all 12 possible notes in a given piece of music.

Instead, we tend to roughly limit the notes we use to the notes in a chosen musical scale.

This way we can create music with a smaller subset of notes that are known to work well together.

A musical scale is the word we use to talk about a group of musical notes that are in ascending or descending order of pitch.

2.1 Chromatic Scale

The most fundamental scale is called the chromatic scale, which is just a fancy way of saying a scale that contains all 12 notes of our musical system.

Like I mentioned above, normally we don't use all 12 possible notes in a piece of music. For this reason, the chromatic scale is rarely used on it's own. The chromatic scale is instead just the basis upon which other scales are created.

2.2 Diatonic Scales

A diatonic scale is a 7-note scale formed with notes that are separated either by whole steps or half steps.

In a diatonic scale, 5 of the notes are a whole step apart and 2 of the notes are a half step apart. The 2 main types of diatonic scales are major scales and natural minor scales.

Diatonic scales are the main type of scale used in Western music.

2.3 Major Scales

Major scales are a type of diatonic scale that's formed with notes that are in this pattern of whole steps and half steps:

You can start on any of the 12 musical notes, and then pick notes that follow that pattern of whole steps and half steps and you'll have the major scale for that note.

What this means is that there are 12 possible major scales, one starting on each of the 12 possible notes.

Major scales are named by the starting note, called the root note of the scale. For example, a major scale starting on the note D is called a D major scale.

The easiest scale to remember is the C major scale, which is simply all the white notes on the piano, all natural notes with no sharps or flats:

play C major scale up and down

Looking at the piano key configuration for the C major scale, we get a visual reminder of the pattern of whole steps and half steps that form the major scale:

Since the C major scale uses only the white keys, The set of 3 black keys followed by two white keys next to each other, then a set of 2 black keys create that pattern (Whole Whole Half Whole Whole Whole Half).

If you're playing notes on the piano and sticking to only the white notes, you're playing notes from the C major scale. Or, it could mean you're playing notes from the A natural minor scale, more on that later when we talk about relative minor.

Diatonic scales, which major scales are a part of, have 7 notes per scale, however the first note of the scale is often repeated to complete the octave. So 7-note scales will often be spelled out like this: G A B C D E F♯ G

Music based upon the notes of a major scale tends to sound happy and uplifting, however it's quite possible to make sad-sounding music using a major scale.

2.4 Natural Minor Scales

Natural minor scales, often just called minor scales, are a type of diatonic scale that's formed with notes that are in this pattern of whole steps and half steps:

There are 3 types of minor scales: natural minor, harmonic minor and melodic minor. The "default" one is the natural minor scale and when, for example, someone says the B minor scale, what is most often implied is the B natural minor scale.

Music based upon the notes of a minor scale tends to sound sad and moody, however it's quite possible to make happy-sounding music using a minor scale.

The easiest minor scale to remember is the A minor scale, which is also just the white keys on the piano:

play A minor scale up and down

But wait, what?! How can two scales one major and one minor use the same exact notes, you might wonder. The reason is that we start the scale on a different note. Read on to the following section to learn how that works...

2.5 Relative Minor & Major

Every major scale has a natural minor scale that has all the same notes, just played in a different order. Similarly, every natural minor scale has a major scale that has all the same notes, played in a different order. This is called a relative major or minor.

The reason why that works is that when we start a scale on a different note, we get a different order of half steps and whole steps in between the notes, and that creates a different sound for that scale.

You'll learn more about that in a following section when we talk about keys and tonal center.

An easy way to know which scale is a relative major or minor of a given scale is using the circle of fifths, which will be covered later in this guide.

For now, you can just keep in mind that every major and natural minor scale has relative scale of the opposite quality that contains the same notes, but played starting on a different note.

📆 Stay tuned, this guide is still in development and this section as well as the remaining sections are coming up soon!