Introduction to Music Theory
· I reply to every message on SignalMusic theory isn't as complicated as you thought. I'm unsure whether it is snobbery or I've just never been taught 'the right way'. Regardless, here's how I made sense of it.
The fundamentals to music starts with the distance (interval) between notes.
Find the ♠ note on the piano keys below. Now, locate the adjacent key (♥). This distance is called a semitone. Find the key next to that (♦). Two semitones make up a whole tone (♠ to ♦).
___________________________
| | | | | | | | | | | | |
| | | | | | | | | | | | |
| |♥| | | | | | | | | | |
| |_| |_| | |_| |_| |_| |
| | | | | | | |
| ♠ | ♦ | | | | | |
|___|___|___|___|___|___|___|
Notes and their names
A common way to refer notes is by letters of the alphabet.
Every culture has their own understanding of music. What I will cover here is a very Western take.
Find the C note by locating the white key to the left of the two-black-key group; that key is C (♠ on the keyboard above).
From there, the whole tone notes are C → D → E → F → G → A → B. Teachers often start from C because it is an easy reference point on the keyboard.
_______________________________________
| | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | | | |
| |_| |_| | |_| |_| |_| | |_| |_| |
| | | | | | | | | | |
| C | D | E | F | G | A | B | C | D | E |
|___|___|___|___|___|___|___|___|___|___|
In between the tones there are sharps (♯) or flats (♭). They are the same pitch on a piano and which name you use depends on some rules I will not cover here.
Start with C and go up one semitone to C♯ (same as D♭). Go down a semitone from G you get G♭ (also F♯).
___________________________
| | | | | | | | | | | | |
| D♭| | | | | | | | | | |
| C♯| | | | |G♭ | | | | |
| |_| |_| | |_| |_| |_| |
| ↗ | | | | ↖ | | |
| C | | | | G | | |
|___|___|___|___|___|___|___|
Scales
Most Western music is based on groupings of fixed distances called musical scales. (And variations on scales called modes.)
For example, a major scale is always in the fixed intervals of tone-tone-semitone-tone-tone-tone-semitone (1-1-½-1-1-1-½).
C major scale
_______________________________________
| | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | | | |
| |_| |_| | |_| |_| |_| | |_| |_| |
| 1 1 ½ 1 1 1 ½ | | |
| o | • | • | • | • | • | • | o | • | • |
|___|___|___|___|___|___|___|___|___|___|
A scale covers an octave and then repeats; albeit in a pitch 12 semitones lower or higher.
In the plain-text graphs, I use o to denote the starting note (also called the tonic, the key, root, or home).
From the tonic, everything else is 'calculated'.
Composers use different scales to create different moods. Major scales might sound bright, happy, or stable. Minor scales sound sad, dark, or tense. Modes (scale variations) give distinct flavors:
- Dorian feels jazzy/folk,
- Phrygian sounds exotic or tense,
- Lydian sounds dreamy.
Chords
Chords are groupings of notes that sound well together. We’ll use a common chord as example: the major triad. Triad meaning ‘three notes’.
Again, it’s all about the distance between notes. For a major triad:
- The distance from the first to the second note is 4 semitones.
- The distance from the second to the third note is 3 semitones.
Count them on the keys below.
___________________________
| | | | | | | | | | | | |
| |1| |3| | |2| | | | | |
| | | | | | | | | | | | |
| |_| |_| | |_| |_| |_| |
| | 2 | 4 | 1 | 3 | | |
| o | | • | | • | | |
|___|___|___|___|___|___|___|
Play the C, E and G notes together and you’ll hear a C major chord.
Of course, major triads are not the only chords. There’s also minor, diminished, and augmented chords. There are seventh chords, ninth chords, suspended chords, and extended chords. And combinations and weirdness in between. For the sake of simplicity I will not cover them.
Also, you can invert chords by putting the second or third note in the bass. A C is still a C wherever you play it.
Harmony and progression
Good sounding chords supporting that melody is called harmony. Composers sequence chords (chord progressions) from the scale to create interesting harmonies.
We’re about to travel up and down the scale, so I’ll use Roman numerals to name the chords built on each scale 'note'.
Below an example of the C major scale and a more complex E harmonic minor scale. The casing (big or small letters) on the numerals indicate the quality of the chord.
- Uppercase = major chord (4 semitones + 3 semitones).
- Lowercase = minor chord (3 + 4)
- ° = diminished (3 semitones + 3 semitones).
- + = augmented (4 + 4). In general, all the chords should fit in the scales. There are exceptions like borrowed chords, but … simplicity.
C major scale
____________________________
| | | | | | | | | | | | |
| | | | | | | | | | | | |
| | | | | | | | | | | | |
| |_| |_| | |_| |_| |_| |
| | | | | | | |
| o | • | • | • | • | • | • |
|___|___|___|___|___|___|___|
I ii iii IV V vi vii°
E harmonic minor scale
ii° vii°
_______________________________________
| | | | | | | | | | | | | | | | | |
| | | | | | |•| | | | | | | | |•| |
| | | | | | | | | | | | | | | | | |
| |_| |_| | |_| |_| |_| | |_| |_| |
| | | | | | | | | | |
| | | o | | • | • | • | • | | |
|___|___|___|___|___|___|___|___|___|___|
I III+ iv V VI
Every place in the scale has a role.
- I — tonic: home, stable.
- ii and IV — subdominants: move away from home, prepare change.
- V and vii° — dominants: create tension that wants to resolve back to I.
A common pattern, for example, is to go from tonic → subdominant → dominant → tonic.
Other common progressions are:
- I – V – vi – IV : a pop staple.
- ii – V – I : classic jazz cadence.
- vi – IV – I – V : common pop ballad loop
- I – vi – IV – V : 1950s progression; gentle movement with clear return.
Don’t feel limited by four chords, by the way. Or sticking to one scale the whole composition. Or the same key. Experiment. Make interesting music. Please, the world needs more interesting music!
Your practice
With these building blocks, you can now start composing music yourself.
- Pick a note (key).
- Choose a scale.
- Choose a starting chord (I is safest).
- Move to a chord that changes role (try I → IV).
- Add a dominant (V).
- Return to I and feel the resolution.
- Repeat it or vary to make musical phrases.
That’s honestly all there is to it.
Things I simplified and outright skipped
- We often stack additional notes (from the scale, like the third note) on top of triads to make more interesting chords.
- Voice leading is moving each note from one chord to the next as smoothly as possible. Good voice leading makes progressions avoid jarring jumps.
- I completely skipped rhythm and meter. But it is HUGE part of music. I assumed you already knew this.
There is so much more to learn about music.
A piano generator
I adore plain text solutions. The longevity, ease of use, the ability to just jot it in my journal as I go. So, here's a ascii piano generator.