Understanding Intervals
A Comprehensive Lesson
Intervals are the building blocks of music, defining the distance between two pitches. In harmony, intervals occur when notes are played simultaneously, creating consonance or dissonance. This lesson explores intervals, their types, emotional effects, formulas, and practical applications.
1. What Are Intervals?
An interval measures the distance between two notes, determined by:
- Quantity: The number of letter names (e.g., C to E is a third).
- Quality: Refines the interval using terms like major, minor, perfect, augmented, or diminished.
2. Types of Intervals
By Quality
default:
Piano.Keyboard:
children: C,F,G
first: C0
last: B0
activeColor: [null, orange, burlywood]
- Perfect (P): Unisons, 4ths, 5ths, and octaves (stable, consonant).
default:
Piano.Keyboard:
showKeyName: true
children: C,D,E,A,B
first: C0
last: B0
activeColor: [null, orange, burlywood, blanchedalmond, salmon, beige]
-
Major (M)/Minor (m): 2nds, 3rds, 6ths, 7ths (major = bright; minor = sad).
-
Augmented (A)/Diminished (d): Expanded or contracted intervals (tense, dissonant).
By Semitones
| Interval | Semitones | Example (C as root) | Emotional Effect |
|---|---|---|---|
| Perfect Unison | 0 | C-C | Stability, emphasis |
| Minor Second (m2) | 1 | C-C#/D♭ | Dissonant, suspenseful |
| Major Second (M2) | 2 | C-D | Neutral, marching |
| Minor Third (m3) | 3 | C-D#/E♭ | Sad, melancholy |
| Major Third (M3) | 4 | C-E | Happy, bright |
| Perfect Fourth (P4) | 5 | C-F | Open, uplifting |
| Tritone (A4/d5) | 6 | C-F♯/G♭ | Unsettling, tense |
| Perfect Fifth (P5) | 7 | C-G | Strong, powerful |
| Minor Sixth (m6) | 8 | C-G#/A♭ | Mysterious, jazzy |
| Major Sixth (M6) | 9 | C-A | Warm, soothing |
| Minor Seventh (m7) | 10 | C-A#/B♭ | Bluesy, unresolved |
| Major Seventh (M7) | 11 | C-B | Tense, yearning |
| Perfect Octave | 12 | C-C | Complete, resonant |
3. Sound Effects & Emotional Impact
- Consonant Intervals: P1, P4, P5, M3, m3 (stable, restful).
Example: A perfect fifth (C-G) evokes power (e.g., rock power chords). - Dissonant Intervals: m2, Tritone, M7 (tense, needing resolution).
Example: A tritone (C-F♯) creates unease (used in horror soundtracks).
4. Interval Formulas & Inversions
- Inversion Rule: Flip the interval (e.g., C-E↑ becomes E-C↓).
- Quantity:
9 - Original = Inverted(e.g., M3 inverts to m6). - Quality: Major ↔ Minor, Perfect ↔ Perfect, Augmented ↔ Diminished.
- Quantity:
- Chord Construction:
- Major Triad = Root + M3 + P5 (C-E-G).
- Minor Triad = Root + m3 + P5 (C-E♭-G).
5. Cheatsheet: Quick Reference
| Concept | Key Points |
|---|---|
| Qualities | Perfect, Major, Minor, Augmented, Diminished |
| Semitone Guide | Use the table above for interval distances. |
| Emotional Use | Happy: M3, M6; Sad: m3, m6; Tense: m2, Tritone |
| Inversions | Add to 12 semitones (e.g., P4 inverts to P5). |
6. Practical Tips
- Ear Training: Use reference songs (e.g., "Here Comes the Bride" = P4).
- Composing: Use consonant intervals for choruses, dissonance for drama.
- Avoid Pitfalls: Remember 4ths/5ths are perfect, not major/minor.
7. Applications in Music
- Pop: Major thirds for uplifting choruses.
- Jazz: Minor sevenths for bluesy progressions.
- Film Scores: Tritones for suspense (e.g., The Simpsons theme).
Mastering intervals unlocks harmonic creativity. Practice identifying them by ear and experiment in compositions! 🎵
