Music theory: the fundamentals

Music is the formation of sound. Put another way, organizing sounds in a specific way is music. Broadly: music is beat, music is rhythm, music is balance, music is scale, music is interval, and so much more — after all, in a way, music is life.

Music can navigate emotion, heal wounds, and ultimately touch the soul. It's something you can feel without ever understanding the meaning of it.

Music theory

The arena of music is limitless, so we can't really box it in with rules. Still, there are theories that help us understand it in an orderly way.

Music theory is the study — or the formula — of music. It shows how a piece of music is formed in detail. It guides, it interprets, and it communicates. By understanding music theory, it gets a little easier to play with confidence.

In this article I go through the basics that form the gist of overall music theory. Let's get started.

Music notes

In music, a note is a symbol denoting a musical sound — so, simply, a note is sound itself. There are seven distinct notes: A, B, C, D, E, F, G.

Pitch

Each note has its own pitch, tone, or sound. The pitch of a note is how high or low it is. In physics, it's measured in a unit called Hertz.

Each note represents a frequency of sound. "A" is 440 Hz. "A" in the next octave is 880 Hz — exactly double the previous frequency. That's why, despite being different frequencies, they sound the "same," and we identify both as the same note.

The 12 notes of music

There aren't seven notes within an octave, but twelve. How? Because five of them double as "sharps" or "flats":

A, A#/B♭, B, C, C#/D♭, D, D#/E♭, E, F, F#/G♭, G, G#/A♭

The difference from one note to another isn't measured by a tone, but by a semitone — the smallest difference between two notes. For instance, A to B is a tone, whereas A to A# is a semitone.

On a keyboard there are white keys and black keys:

• White keys: the "natural" notes in a scale (A, B, C, D, E, F, G)
• Black keys: the "flat" and "sharp" notes (A#/B♭, C#/D♭, D#/E♭, F#/G♭, G#/A♭)

Intervals

Simply put, an interval is the distance between two notes. Because notes sit at different distances from each other, those distances give us different intervals. The naming convention follows both the distance and the type — measured by half steps, whole steps, and position.

• Playing two or more notes at the same time creates harmonic intervals (chords)
• Playing single notes one after another creates melodic intervals (melodies)

Intervals are named by size (distance) and quality (type). For example, M7 = Major 7, where major is the quality and 7 is the size.

Quality: there are five interval qualities — major (M), minor (m), perfect (P), augmented (A/+), and diminished (dim/o). These prefixes describe the quality.

Size: the interval number represents the number of half-steps between two notes. For instance:

• Unison
• Major 2nd: two half-steps
• Major 3rd: four half-steps
• Major 4th: five half-steps
• Major 5th: seven half-steps
• Major 6th: nine half-steps
• Major 7th: eleven half-steps
• Major 8th: twelve half-steps (octave)

And the qualities themselves:

• Perfect: if the top note is in the major key of the bottom note, and the bottom note is in the major key of the top note.
• Major: if the top note is in the major key of the bottom note.
• Minor: if it's a half step smaller than major.
• Diminished: if it's a half step smaller than minor or perfect.
• Augmented: if it's a half step larger than major or perfect.

I'll go deeper into intervals in another article.

Octave

An octave is a kind of interval — it's the distance between the highest and lowest pitch of the same note. More precisely, an octave (or perfect octave) is the interval between one musical pitch and another with double its frequency.

A perfect octave, also called P8, requires 12 semitones. In physics terms, an octave is the distance between one note and another at double its frequency. In Western music, octaves are split into 12 equal intervals, and each one brings us to a new note.

Key signature

First, the key. A key is the menu of 7 different notes — the group of pitches, or scale, that forms the basis of a piece of music.

One more thing matters here: the accidental. An accidental is a note that isn't a member of the key; it shows up only occasionally over the course of a piece. The three main accidentals are sharps, flats, and naturals.

So a key signature tells us two things: which key we're in, and what sharps or flats apply. It's the arrangement of sharp or flat signs on particular lines and spaces of the staff, telling us that the corresponding notes — in every octave — are consistently raised (by sharps) or lowered (by flats) from their natural pitches.

The keys of C major and A minor, having no sharps or flats, have no key signature. The signature also helps you identify the key of a song — its tonal center. If we say a song is "in the key of C," it means the pitch C sounds like the most stable "home note" (or tonic) for that song.

Scale

A scale is any set of musical notes ordered by pitch — a collection of notes from low to high. It's a subset of all available notes, chosen because of the way they relate to each other. Each type of scale has a distinct sound, and many people carry particular emotional associations with particular scales.

Types of scale, by the number of distinct pitches:

• Chromatic: 12 notes per octave
• Octatonic: 8 notes per octave — jazz
• Heptatonic: 7 notes per octave — modern Western
• Hexatonic: 6 notes per octave — Western folk
• Pentatonic: 5 notes per octave — Asian folk music
• Tetratonic: 4 notes; Tritonic: 3 notes; Ditonic: 2 notes

The two most common qualities of scale are major and minor.

Major

Major scales are bright, uplifting, and happy sounding. The interval pattern is W-W-H-W-W-W-H (whole-whole-half-whole-whole-whole-half). There are twelve possible natural major scales.

Minor

Natural minor scales are dark, sad, and emotional sounding. The interval pattern is W-H-W-W-H-W-W. There are twelve possible natural minor scales, plus three variations: natural, harmonic, and melodic.

• Harmonic: W-H-W-W-H-(step and a half)-H
• Melodic: W-H-W-W-W-W-H

By changing the first note and following the pattern, you can construct any major or minor scale. The same goes for any other scale once you know its pattern.

Scale degrees

A scale degree is just the number of a note within a scale. It's useful for indicating the size of intervals and chords, and whether they're major or minor. In the most general sense, it's the number given to each step, usually starting with 1 for the tonic.

Music is all about the creation and release of tension. A scale degree's function relates to how much tension it creates — and it helps you decide what note should follow to resolve that tension. There are seven scale degrees, and these names apply to all major and minor scales:

• 1st — Tonic
• 2nd — Supertonic
• 3rd — Mediant
• 4th — Subdominant
• 5th — Dominant
• 6th — Submediant
• 7th — Leading Tone

Modes

A musical mode is a kind of scale derived from a parent scale. There are seven modes, each a slight variation. They use the same notes and interval patterns as the parent scale — the main difference is the root note used to build it. Starting a scale on a different note defines a new tonal center, giving it distinct melodic character.

Modes come from the earliest forms of Western music, where they were used much like we use keys now. The seven modes, with their starting points:

• I — Ionian (the major scale)
• ii — Dorian (major scale starting on the 2nd degree)
• iii — Phrygian (major scale starting on the 3rd degree)
• IV — Lydian (major scale starting on the 4th degree)
• V — Mixolydian (major scale starting on the 5th degree)
• vi — Aeolian (natural minor; major starting on the 6th degree)
• vii — Locrian (major scale starting on the 7th degree)

Chords

A chord is a combination of two or more notes played together at the same time. It creates harmony, gives texture to a melody, and can even lend rhythm to a song.

The most common chords are triads — three notes. Every chord has a starting note called the root. In C E G, C is the root. So in general, a chord is built from a root, a third, and a fifth.

There are four basic triad types:

• Major — root, major 3rd, perfect 5th
• Minor — root, minor 3rd, perfect 5th
• Augmented — root, major 3rd, augmented 5th
• Diminished — root, minor 3rd, diminished 5th

Major chords sound brighter and happier. A major chord has a "natural third" — the third degree of its major scale. Minor chords sound darker and sadder. A minor chord has a "minor third" (or "flat third") — the third degree of its minor scale.

Diminished chords sound tense, dissonant, and dramatic. Augmented chords sound dissonant, unsettling, and mysterious. These two have qualities that may not sound in perfect harmony — they can feel bizarre or unbalanced, which is exactly why they're so captivating when placed strategically.

A few chords used less often:

Seventh chords add an extra note to the basic triad — a root, a 3rd, a perfect 5th, and a 7th. There are five main types: major, minor, dominant, diminished, and half-diminished.

• Major seventh — thoughtful and soft; jazzy. Root, major 3rd, perfect 5th, major 7th.
• Minor seventh — moody or contemplative; somewhere between happy and sad. Root, minor 3rd, perfect 5th, minor 7th.
• Dominant seventh — strong and restless; common in jazz, blues, hip hop, R&B, and EDM. Root, major 3rd, perfect 5th, minor 7th.

Suspended chords (sus2 & sus4) break the usual root-third-fifth formula. They replace the third with "something else," which makes them less stable and neither major nor minor.

• Sus2: root, 2nd, and 5th (1-2-5) = C D G. The third is replaced by the second.
• Sus4: root, 4th, and 5th (1-4-5) = C F G. The third is replaced by the fourth.

Chord extensions

There are chords beyond the seventh — namely 9th, 11th, and 13th chords. Not all of them are necessary, but the idea is that a chord can extend by adding notes to the basic triad. Extended chords create a richer, more harmonically elaborate sound, and open up more voice-leading possibilities that make progressions more interesting.

Chord inversions

A chord's inversion is defined by which of its notes sits at the bottom. A C-major triad contains C, E, and G; its inversion depends on which of these is the lowest note. The more notes a chord has, the more inversions are possible. Inversions add variation, excitement, and smoother transitions between chords.

Chord progressions

A chord progression (or harmonic progression) is an organized series of chords that supports both melody and rhythm. It provides the ground on which harmony and melody are built.

Conclusion

I hope this is a useful introduction to the fundamentals of music theory — notes, intervals, octaves, keys, key signatures, scales, scale degrees, modes, and chords.

But doing music isn't only about reading theory; it's about intense practice. If you want the best result, combine the two and you can just blast. I'm not calling this finished, either — I'll keep improving it as I find things worth adding. And if you have an insight that could make this better, please don't hesitate to tell me. It would genuinely be appreciated.

Stay tuned.