Music theory can often feel overwhelming, particularly if you’re just starting out or are self-taught. However, it doesn’t have to be that way. Understanding the basics provides a foundational aspect for further musical learning. This guide, based on insights from the Encore Piano Academy, will walk you through the fundamentals of music theory in a structured manner, covering notes, chords, scales, and intervals, and how they all work together.
Table of Contents
The Basic Building Blocks: Notes, Tones, and Semitones
At its core, all music in the Western tradition is made up of just 12 notes. These notes repeat across the instrument, such as a keyboard. On a keyboard, keys are arranged in groups of black and white keys. Specifically, the black keys are in groups of twos and threes, with white keys alongside them. Counting the 7 white keys and 5 black keys in one repeating section gives you the total of 12 notes.
Notes have pitch; moving towards the left on an instrument means going down in pitch, while moving towards the right means going up in pitch.
The distance between these notes is measured using tones and semitones, also known as whole steps and half steps. A semitone is the distance between one key and the very next key, regardless of colour. For example, moving from a white key to an adjacent black key, or from one white key to the very next white key with no black key in between, is a semitone. A tone is simply two semitones. So, to find a tone up from a note, you count two semitones from that note.
Naming the Notes and Accidentals
The white keys are named using the first seven letters of the English alphabet: C, D, E, F, G, A, B. This sequence repeats across the keyboard.
To name the black keys, and to alter the pitch of notes, we use accidentals: sharps, flats, and naturals.
- A sharp sign (#) indicates that you increase a note’s value by one semitone. For example, C sharp (C#) is the black key one semitone above C.
- A flat sign (♭) indicates that you decrease a note’s value by one semitone. For example, B flat (B♭) is the black key one semitone below B.
Each black key typically has two names, one sharp name and one flat name, making them enharmonic notes. The sharp name comes from the white key to its left (e.g., C# is next to C), and the flat name comes from the white key to its right (e.g., D♭ is next to D). So, the black key between C and D can be called C# or D♭.
Accidentals are not limited to black keys. For instance, decreasing C by one semitone gives you B, so B can also be called C flat (C♭). Similarly, increasing E by one semitone gives you F, so F can be called E sharp (E#). Sharps and flats mean increasing or decreasing a note’s value by one semitone.
A natural sign (♮) is used to cancel a sharp or a flat, restoring the note to its original pitch. If you encounter a C# in music notation and the next note is a C, a natur
Intervals: Measuring the Distance Between Notes
An interval is defined as the distance between one note and another note. The distance can be measured by counting the number of semitones between the notes. Since there are 12 notes, there are also 12 main intervals within an octave.
Starting from C, here are the intervals based on the number of semitones:
- 0 semitones: Unison (C to C)
- 1 semitone: Minor 2nd (C to C# or D♭)
- 2 semitones: Major 2nd (C to D)
- 3 semitones: Minor 3rd (C to D# or E♭)
- 4 semitones: Major 3rd (C to E)
- 5 semitones: Perfect 4th (C to F)
- 6 semitones: Tritone (C to F# or G♭). This interval sits in the middle of the 12 intervals and is sometimes called the “devil’s interval” due to its dissonant sound.
- 7 semitones: Perfect 5th (C to G)
- 8 semitones: Minor 6th (C to G# or A♭)
- 9 semitones: Major 6th (C to A)
- 10 semitones: Minor 7th (C to A# or B♭)
- 11 semitones: Major 7th (C to B)
- 12 semitones: Perfect 8th or Octave (C to the next C)
Intervals have different qualities: seconds, thirds, sixths, and sevenths can be major or minor; unisons, fourths, fifths, and eighths are perfect; and the tritone is unique. Understanding the sound of each interval is crucial as they are the building blocks for chords and scales.
Scales: Groups of Notes with Specific Intervals
A scale is a group of notes separated by specific intervals. There are many types of scales, but the most common are major and minor.
Major Scales All major scales sound similar because the distance between the notes is always the same, only the starting note changes. You can construct any major scale using a simple formula based on tones and semitones:
Tone – Tone – Semitone – Tone – Tone – Tone – Semitone
Let’s construct the C Major scale:
- Start with C.
- A tone from C is D.
- A tone from D is E.
- A semitone from E is F. (First part: Tone Tone Semitone – C D E F)
- A tone from F is G. (Midpoint Tone – G)
- A tone from G is A.
- A tone from A is B.
- A semitone from B is C. (Last part: Tone Tone Semitone – A B C)
Putting it together, the C Major scale notes are C, D, E, F, G, A, B, C.
Let’s try the D Major scale:
- Start with D.
- A tone from D is E.
- A tone from E is F# (remember, E to F is a semitone, so two semitones is E to F#).
- A semitone from F# is G. (Tone Tone Semitone – D E F# G)
- A tone from G is A. (Midpoint Tone – A)
- A tone from A is B.
- A tone from B is C# (remember, B to C is a semitone, so two semitones is B to C#).
- A semitone from C# is D. (Tone Tone Semitone – B C# D)
The D Major scale notes are D, E, F#, G, A, B, C#, D. You can construct a major scale starting from any of the 12 notes using this formula.
Minor Scales Minor scales are also derived from major scales. One way to find a minor scale is to locate the relative minor. The relative minor scale starts on the sixth note of a major scale and uses the same notes as that major scale. For example, the notes of the C Major scale are C, D, E, F, G, A, B, C. The sixth note is A. Starting the scale from A using these notes gives you the A natural minor scale: A, B, C, D, E, F, G, A.
There are three types of minor scales:
- Natural Minor: This is the basic minor scale derived from the relative major, using the same notes.
- Harmonic Minor: This scale is based on the natural minor, but the seventh note is sharpened (increased by a semitone). For A natural minor (A, B, C, D, E, F, G, A), the 7th note is G. Sharpening it gives you G#, so the A harmonic minor scale is A, B, C, D, E, F, G#, A. This gives it a slightly different feel.
- Melodic Minor: This scale is different ascending and descending.
- Ascending: You sharpen the sixth and seventh notes of the natural minor scale. For A natural minor, this means sharpening F and G. The A melodic minor ascending is A, B, C, D, E, F#, G#, A.
- Descending: You play the notes of the natural minor scale. The A melodic minor descending is A, G, F, E, D, C, B, A.
The relative minor of D Major is B minor, as B is the sixth note of the D Major scale (D, E, F#, G, A, B, C#, D). The B natural minor scale is B, C#, D, E, F#, G, A, B. The B harmonic minor sharpens the 7th (A becomes A#): B, C#, D, E, F#, G, A#, B. The B melodic minor ascending sharpens the 6th and 7th (G becomes G#, A becomes A#): B, C#, D, E, F#, G#, A#, B. The B melodic minor descending is the same as B natural minor: B, A, G, F#, E, D, C#, B.
Chords: Notes Played Together
A chord is a group of notes that are played simultaneously. The mood or emotion associated with a chord depends on its type. There are four main types of three-note chords (triads) commonly found in Western music: major, minor, augmented, and diminished.
- Major chords are often associated with positive or happy moods.
- Minor chords tend to be darker and melancholic.
- Augmented chords can sound unsettling.
- Diminished chords often sound dissonant or “evil”.
These chords are constructed using formulas based on intervals from a starting note, often referencing the notes of the corresponding major scale. Let’s use the C Major scale (C, D, E, F, G, A, B) and its notes numbered 1 through 7 to build these chords starting from C:
- Major Chord Formula: 1 – 3 – 5
- C Major: C (1st note of C Major scale), E (3rd), G (5th) = C E G.
- Minor Chord Formula: 1 – 3♭ – 5
- To make a minor chord, you take the major chord formula and flatten the 3rd note (lower it by one semitone).
- C Minor: C (1), E♭ (flattened 3rd), G (5) = C E♭ G.
- Augmented Chord Formula: 1 – 3 – 5#
- To make an augmented chord, you take the major chord formula and sharpen the 5th note (raise it by one semitone).
- C Augmented: C (1), E (3), G# (sharpened 5th) = C E G#.
- Diminished Chord Formula: 1 – 3♭ – 5♭
- To make a diminished chord, you take the major chord formula and flatten both the 3rd and the 5th notes.
- C Diminished: C (1), E♭ (flattened 3rd), G♭ (flattened 5th) = C E♭ G♭.
The difference in the sound of these chords is directly related to the intervals between the root note (the starting note) and the other notes. For instance, a C Major chord contains a major third (C to E) and a perfect fifth (C to G). A C Minor chord contains a minor third (C to E♭) and a perfect fifth (C to G).
Chords Within Scales
You can also derive chords directly from the notes of a scale. By taking alternate notes starting from each note of the major scale (1-3-5), you can build seven unique three-note chords.
Using the C Major scale (C D E F G A B C):
- Starting on C (1st note): C E G = C Major
- Starting on D (2nd note): D F A = D minor
- Starting on E (3rd note): E G B = E minor
- Starting on F (4th note): F A C = F Major
- Starting on G (5th note): G B D = G Major
- Starting on A (6th note): A C E = A minor
- Starting on B (7th note): B D F = B diminished
- Starting on the next C (Octave): C E G = C Major
The quality of the chord built on each degree of a major scale is consistent regardless of the starting key:
- 1st, 4th, and 5th degrees yield Major chords. These are often called primary chords and are frequently used in songs written in that key.
- 2nd, 3rd, and 6th degrees yield minor chords.
- 7th degree yields a diminished chord.
You can apply this derivation method to any major scale.
Similarly, you can derive chords from a minor scale. Using the harmonic minor scale (which has a unique set of intervals making it suitable for chord derivation) and taking alternate notes (1-3-5) from each degree gives a different set of chord qualities.
Using the A Harmonic Minor scale (A B C D E F G# A):
- Starting on A (1st note): A C E = A minor
- Starting on B (2nd note): B D F = B diminished
- Starting on C (3rd note): C E G# = C augmented
- Starting on D (4th note): D F A = D minor
- Starting on E (5th note): E G# B = E Major
- Starting on F (6th note): F A C = F Major
- Starting on G# (7th note): G# B D = G# diminished
These are the chord qualities you will find when deriving chords from a harmonic minor scale.
Seventh Chords: Adding a Fourth Note
While major, minor, augmented, and diminished chords are three-note chords, seventh chords add a fourth note. These add richness or “spice” to the harmony. You derive a seventh chord by taking the first, third, fifth, and seventh notes from a scale.
Two common types of seventh chords are the dominant 7th and the diminished 7th. They have specific formulas:
- Dominant 7th Formula: 1 – 3 – 5 – 7♭
- For a C dominant 7th chord, you take C, E, G (the 1, 3, 5 from C Major) and add the flattened 7th note of the C Major scale (B♭). The notes are C E G B♭.
- Diminished 7th Formula: 1 – 3♭ – 5♭ – 7 double flat
- A double flat (♭♭) means lowering the note’s value by two semitones.
- For a C diminished 7th chord, you take C, E♭, G♭ (1, 3♭, 5♭ from C Diminished) and add the double-flattened 7th note of the C Major scale (B♭♭). A B♭♭ is enharmonically equivalent to A. The notes are C E♭ G♭ B♭♭.
These seventh chords are not just theoretical constructs; they are inherently found within scales.
- In a major scale, the fifth note creates a dominant seventh chord when stacking the 1st, 3rd, 5th, and 7th scale degrees from that fifth note. For example, in C Major, the 5th note is G. Stacking alternate notes up to the 7th from G (G, B, D, F) gives you a G dominant 7th chord.
- In a harmonic minor scale, the seventh note creates a diminished seventh chord when stacking the 1st, 3rd, 5th, and 7th scale degrees from that seventh note. For example, in A Harmonic Minor, the 7th note is G#. Stacking alternate notes up to the 7th from G# (G#, B, D, F) gives you a G# diminished 7th chord.
Conclusion
Understanding these fundamental concepts – notes, intervals, scales, and chords – is essential because music theory isn’t just abstract information; it is the foundation behind every note and chord you play and hear. By grasping these basics, you gain a deeper understanding of how music works, opening up possibilities for playing, composing, and improvising.
