Intervals: The Building Blocks of Music
Learn about intervals - the distances between notes that form the foundation of scales, chords, and melodies.
What are Intervals?
An interval is the distance between two notes. Understanding intervals is fundamental to music theory because they form the building blocks of scales, chords, and melodies. Intervals are measured in two ways: by the number of letter names they span (generic interval) and by the number of semitones/half steps (specific interval).
Why Intervals Matter
- Scale Construction: Scales are built from specific interval patterns
- Chord Building: Chords are constructed by stacking intervals (usually thirds)
- Melodic Recognition: Recognizing intervals by ear helps with transcribing and playing by ear
- Harmony: Intervals determine whether harmony sounds consonant (stable) or dissonant (tense)
- Composition: Understanding intervals helps you write better melodies and harmonies
Measuring Intervals
Intervals have two components: the generic interval (the number of letter names) and the quality (perfect, major, minor, augmented, or diminished).
Generic Intervals
The number of letter names an interval spans:
- 2nd: C to D (2 letter names)
- 3rd: C to E (3 letter names)
- 4th: C to F (4 letter names)
- 5th: C to G (5 letter names)
- 6th: C to A (6 letter names)
- 7th: C to B (7 letter names)
- 8th (Octave): C to C (8 letter names)
Interval Quality
The quality describes the exact size of the interval:
- Perfect: Unison, 4th, 5th, Octave (very stable)
- Major: 2nd, 3rd, 6th, 7th (larger version)
- Minor: 2nd, 3rd, 6th, 7th (smaller version, one semitone less)
- Augmented: Any interval raised by a semitone
- Diminished: Any interval lowered by a semitone
All Intervals from C
Here are all intervals starting from C, showing their size in semitones, quality, and characteristics:
Unison (Perfect Prime)
0 semitones
Example: C to C
Sound: Same note, no distance
Use: Used for emphasis and unison passages
Minor Second
1 semitones
Example: C to C♯ or E to F
Sound: Very close, tense, dissonant
Use: Creates tension, used in chromatic passages
Major Second
2 semitones
Example: C to D
Sound: Stepwise, consonant
Use: Most common melodic interval, scale steps
Minor Third
3 semitones
Example: C to E♭ or A to C
Sound: Sad, melancholic
Use: Defines minor chords and scales
Major Third
4 semitones
Example: C to E
Sound: Happy, bright
Use: Defines major chords and scales
Perfect Fourth
5 semitones
Example: C to F
Sound: Stable, open
Use: Common in bass lines and power chords
Tritone (Augmented Fourth/Diminished Fifth)
6 semitones
Example: C to F♯ or C to G♭
Sound: Very tense, unstable, "devil's interval"
Use: Creates maximum tension, needs resolution
Perfect Fifth
7 semitones
Example: C to G
Sound: Very stable, consonant, powerful
Use: Foundation of chords, power chords
Minor Sixth
8 semitones
Example: C to A♭ or E to C
Sound: Melancholic, expressive
Use: Common in melodies, creates emotion
Major Sixth
9 semitones
Example: C to A
Sound: Warm, consonant
Use: Common in melodies, adds color
Minor Seventh
10 semitones
Example: C to B♭
Sound: Jazzy, smooth
Use: Defines dominant 7th and minor 7th chords
Major Seventh
11 semitones
Example: C to B
Sound: Tense, needs resolution
Use: Defines major 7th chords, creates tension
Octave (Perfect Eighth)
12 semitones
Example: C to C (next octave)
Sound: Same note, different octave, very stable
Use: Doubling, octave leaps, register changes
Interval Types and Qualities
Understanding the different types of intervals and their qualities helps you identify and use them effectively:
Perfect Intervals
Examples: Unison, Fourth, Fifth, Octave
Very stable and consonant. Cannot be major or minor.
Can be augmented (raised) or diminished (lowered)
Major/Minor Intervals
Examples: Second, Third, Sixth, Seventh
Can be major (larger) or minor (smaller). Major intervals are one semitone larger than minor.
Can be augmented or diminished beyond major/minor
Augmented Intervals
Examples: Any interval raised by a semitone
Larger than major or perfect intervals. Creates tension.
Perfect intervals become augmented, major intervals become augmented
Diminished Intervals
Examples: Any interval lowered by a semitone
Smaller than minor or perfect intervals. Creates tension.
Perfect intervals become diminished, minor intervals become diminished
Consonant vs. Dissonant Intervals
Intervals are classified as either consonant (stable, pleasant) or dissonant (tense, needing resolution):
Consonant Intervals
Stable, pleasant-sounding intervals that don't need resolution:
- Perfect Consonances: Unison, Perfect 4th, Perfect 5th, Octave
- Imperfect Consonances: Major 3rd, Minor 3rd, Major 6th, Minor 6th
- These intervals sound stable and can be held without creating tension
- Form the foundation of chords and stable harmony
Dissonant Intervals
Tense intervals that create a need for resolution:
- Very Dissonant: Minor 2nd, Major 7th, Tritone
- Moderately Dissonant: Minor 7th, Major 2nd
- These intervals create tension and typically resolve to consonant intervals
- Essential for creating musical interest and forward motion
Historical Context
What is considered consonant or dissonant has changed over time. In medieval music, even thirds were considered dissonant! In modern music, we have a broader acceptance of dissonance, especially in jazz and contemporary classical music. However, the basic principles remain: perfect intervals and major/minor thirds and sixths are generally consonant, while seconds, sevenths, and tritones are generally dissonant.
Compound Intervals
Compound intervals are intervals larger than an octave. They are named by adding 7 to the simple interval name:
Simple Intervals:
- 2nd → Compound 9th (octave + 2nd)
- 3rd → Compound 10th (octave + 3rd)
- 4th → Compound 11th (octave + 4th)
- 5th → Compound 12th (octave + 5th)
Examples:
- C to D (2nd) → C to D (9th) - same quality
- C to E (3rd) → C to E (10th) - same quality
- Compound intervals have the same quality as their simple counterparts
- Used in extended chords (9ths, 11ths, 13ths)
Inverting Intervals
Interval inversion occurs when you flip an interval so the lower note becomes the higher note (or vice versa). Inverting an interval changes both its size and quality in predictable ways:
Inversion Rules
Size Changes:
- 2nd ↔ 7th (2 + 7 = 9)
- 3rd ↔ 6th (3 + 6 = 9)
- 4th ↔ 5th (4 + 5 = 9)
- Unison ↔ Octave (0 + 8 = 8, special case)
Quality Changes:
- Major ↔ Minor
- Perfect ↔ Perfect
- Augmented ↔ Diminished
- Example: Major 3rd (C-E) inverts to Minor 6th (E-C)
Recognizing Intervals by Ear
Developing the ability to recognize intervals by ear is a crucial skill for musicians. Here are some famous songs that use specific intervals to help you remember them:
Interval Recognition Songs
- Minor 2nd: "Jaws" theme, "Für Elise" opening
- Major 2nd: "Happy Birthday" (first two notes), "Do-Re-Mi"
- Minor 3rd: "Greensleeves", "So Long, Farewell"
- Major 3rd: "Oh When the Saints", "Kumbaya"
- Perfect 4th: "Here Comes the Bride", "Amazing Grace"
- Tritone: "The Simpsons" theme, "Maria" (West Side Story)
- Perfect 5th: "Twinkle Twinkle Little Star", "Star Wars" theme
- Minor 6th: "The Entertainer", "Love Story" theme
- Major 6th: "My Bonnie Lies Over the Ocean", "NBC" chimes
- Minor 7th: "Somewhere" (West Side Story), "Watermelon Man"
- Major 7th: "Take On Me" (chorus), "Bali Hai"
- Octave: "Somewhere Over the Rainbow", "Willow Weep for Me"
Interactive Practice
How many semitones are in a perfect fifth?
What interval quality can a perfect 5th become when raised by a semitone?
Practical Applications
Understanding intervals has many practical applications in music:
Building Scales
Scales are built from specific interval patterns. For example, the major scale uses: W-W-H-W-W-W-H (where W = whole step = major 2nd, H = half step = minor 2nd).
Building Chords
Chords are constructed by stacking intervals. A major triad uses: root + major 3rd + perfect 5th. Understanding intervals helps you build any chord.
Melodic Writing
Different intervals create different melodic effects. Stepwise motion (2nds) is smooth, while leaps (3rds, 4ths, 5ths+) create more dramatic melodies.
Ear Training
Recognizing intervals by ear helps with transcribing music, playing by ear, and understanding harmony. Practice identifying intervals in songs you know.
Daily Practice
Practice these exercises to master intervals:
Basic Exercises
- Play and identify all intervals from C on your instrument
- Practice singing intervals using familiar songs as references
- Identify intervals in sheet music you're reading
- Build scales using interval patterns
Advanced Exercises
- Identify intervals by ear without reference notes
- Practice interval inversions
- Build chords by stacking intervals
- Transcribe melodies by identifying intervals
- Practice compound intervals
Key Takeaways
- Intervals are the distances between notes, measured in semitones and letter names
- Intervals have qualities: perfect, major, minor, augmented, or diminished
- Perfect intervals (unison, 4th, 5th, octave) are very stable and consonant
- Major/minor intervals (2nd, 3rd, 6th, 7th) can be either major (larger) or minor (smaller)
- Consonant intervals sound stable; dissonant intervals create tension and need resolution
- Compound intervals are larger than an octave and are named by adding 7 to the simple interval
- Interval inversion flips the interval, changing size and quality in predictable ways
- Recognizing intervals by ear is essential for ear training and playing by ear
- Intervals form the foundation of scales, chords, and melodies
- Practice with familiar songs helps memorize interval sounds