The minor 7th is certainly a real and useful musical interval. In music theory, an interval refers to the distance between two pitches. The minor 7th interval specifically consists of 10 semitones. This interval appears in many different contexts and helps provide color and interest to melodies and harmonies.
What is a minor 7th interval?
Let’s break this down step-by-step:
- An interval is the distance between two musical pitches.
- “Minor” refers to the quality of the interval. Minor intervals sound tense or ominous.
- “7th” indicates that the interval spans seven letter names (e.g. C to B).
So a minor 7th interval occurs between two notes that are 10 semitones apart, spanning seven letter names, and has a tense, ominous sound.
Interval size
The minor 7th interval contains 10 semitones. For example, from C to B is a minor 7th interval because there are 10 semitones between them (C, C#, D, D#, E, F, F#, G, G#, A, B). This is what gives the minor 7th its distinctive sound.
Letter names
A minor 7th interval spans seven letter names. For example, C up to B spans C, D, E, F, G, A, B. The wide gap of seven letter names contributes to the unsettled character of the interval.
Minor quality
Minor intervals sound tense or ominous compared to the more stable major intervals. This comes from the specific ratio of frequencies between the notes. The minor quality is what gives the minor 7th its dark, edgy sound.
Where does the minor 7th interval occur?
The minor 7th interval shows up in many contexts in music. Here are some of the most common places you can find the minor 7th:
Dominant 7th chords
Dominant 7th chords are major triads with an added minor 7th. For example, C7 is C-E-G-Bb. The Bb creates a minor 7th above the root C. These chords create tension that wants to resolve to a major chord a fifth below the root. For instance, C7 pulls strongly to F major.
Minor key harmony
In minor keys, the 7th scale degree is naturally lowered a semitone. This forms a minor 7th interval above the tonic. So in C minor, the Bb in the key signature creates a minor 7th interval above C. This interval is part of the harmonic fabric of minor keys.
Melodic embellishment
Composers often decorate melodies using non-chord tones like the minor 7th. For example, a melody in C major could embellish by momentarily landing on a Bb before resolving back to A. This adds color and interest.
Modal mixture
Borrowing chords from parallel minor keys interjects more minor 7th intervals. For instance, a piece in C major briefly using an Fm chord adds in a C to Bb minor 7th relationship.
Blues music
Blues music makes extensive use of minor 7th intervals, especially in its characteristic dominant 7th chords. The tension and instability of the minor 7th contributes to the dark, soulful blues sound.
What does the minor 7th interval sound like?
The minor 7th interval has a distinctive tense, edgy sound that gives it a lot of utility in music. Here are some key qualities of its sound:
- Dissonant and unstable
- Creates tension that wants to resolve
- Ominous, dark character
- Gritty and soulful
- Bluesy and melancholic
Sing or play a minor 7th interval like C up to Bb and pay attention to its unique sound. The wide gap combined with the minor quality gives this interval its unsettled vibe. It’s very different from the stable, consonant sound of major intervals like the octave or perfect fifth.
Listen to examples
Here are some musical excerpts with prominent minor 7th intervals to listen to:
- The C7 chord starting each bar in a 12-bar blues progression
- The Bb-A melody in the chorus of Billie Holiday’s “Gloomy Sunday”
- The Eb-D bassline at the start of The White Stripes’ “Seven Nation Army”
- The clash between the C bass and Bb melody during the Jaws theme song
How is the minor 7th interval used in music?
Musicians use the minor 7th in a variety of ways to create tension, instability, interest, and color. Here are some of the most common musical uses of the minor 7th interval:
Resolving in dominant chords
Dominant 7th chords contain a minor 7th above the root. This interval wants to resolve downward by semitone to the third of the following chord. Resolving this tension is one of the minor 7th’s most common functions.
Creating unease
The unsettled sound of the minor 7th can evoke unease, dread, sadness, or longing in music. Composers use this to create an ominous mood, like in the Jaws theme song.
Adding interest to melodies
Melodic embellishments and non-chord tones featuring the minor 7th add color and tension. Composers interject this interval to break from boring stepwise motion in melodies.
Making harmonies richer
Weaving the minor 7th into chord progressions and harmonies adds complexity beyond basic triads. Jazz and blues especially rely on the richness of 7th chords.
Giving a bluesy feel
From soulful vocals to blues guitar solos, the minor 7th communicates the dark, gritty vibe of this genre. It defines the signature blue notes in blues music.
Adding modal mixture
Borrowing chords from a parallel minor key interjects more instances of the minor 7th in a major key context. This modal mixture adds more diverse colors.
Why is the minor 7th important in music theory?
Though it spans just 10 semitones, the minor 7th interval punches far above its weight. Here are some reasons why the minor 7th is so important in music theory:
- It’s featured heavily in dominant 7th chords
- It’s a defining characteristic of minor key harmony
- It provides a dissonant non-chord tone to play with
- It gives a signature bluesy, soulful color
- It allows modal mixture between major and minor keys
- It enables rich-sounding 7th chords
- It provides tension that creates interest and forward motion when resolved
Without the minor 7th as a musical tool, compositions would lose a lot of their tension, moodiness, soul, and color. While it may seem like a humble interval, music would be less interesting without those 10 semitones.
How to remember the minor 7th interval
Here are some tips to help remember the characteristics and sound of the minor 7th interval:
- Visualize the piano keys – Picture an octave on piano keys and count 10 semitones up from C to Bb.
- Think dominant 7th chords – Associate the minor 7th with the C7, F7, etc. used in pop and blues music.
- Listen to examples – Play or listen to music with prominent minor 7ths to get used to the sound.
- Sing it – Audiate and sing a minor 7th melody to experience the interval in action.
- Play it on your instrument – Practicing the fingerings will solidify the sound in your muscle memory.
- Write songs using it – Compose melodies and chord progressions featuring the minor 7th to internalize its sound and function.
With time and active practice, your ears will learn to instantly recognize the ominous, soulful sound whenever a minor 7th interval appears.
Common questions about the minor 7th interval
Here are answers to some frequent questions about the minor 7th interval in music theory:
What are the notes in a minor 7th interval?
The notes of a minor 7th depend on the starting note. But in general, it spans 10 semitones and 7 letter names. For example: C up to Bb, G up to F, D up to C#.
Is it minor 7th or dominant 7th?
A dominant 7th chord contains a minor 7th interval above the root (e.g. G7 has an F, which forms a minor 7th above G). “Minor 7th” and “dominant 7th” refer to the same interval, but in different contexts.
Is the minor 7th stable or unstable?
The minor 7th is considered unstable and dissonant. It creates tension that wants to resolve down by semitone to a more stable note.
What are some songs with a minor 7th?
Songs with prominent minor 7ths include:
- “Hit the Road Jack” – Ray Charles
- “Careless Whisper” – George Michael
- “Creep” – Radiohead
- “I’m Waiting for the Man” – Velvet Underground
- “Jolene” – Dolly Parton
What chord has a minor 7th?
The most common chord with a minor 7th is a dominant 7th chord, like D7 in the key of G major (D-F#-A-C). The C forms a minor 7th above the root D. Minor 7th chords like Cm7 (C-Eb-G-Bb) also contain the interval.
Minor 7th Interval Cheat Sheet
Here is a quick cheat sheet summarizing the minor 7th interval:
| Definition | An interval spanning 10 semitones and 7 letter names, with a tense, ominous sound. |
|---|---|
| Size | 10 semitones |
| Sound | Dissonant, unstable, dark, bluesy |
| Examples |
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| Usage |
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Conclusion
In summary, the minor 7th is a versatile and important interval in music theory. It spans 10 semitones, has an ominous sound, and shows up in dominant chords, minor keys, melodic lines, and blues music. Composers use the minor 7th to create tension and interest. Without this humble interval, music would have far less harmonic richness, melodic color, and emotional expressiveness.
So next time you hear a bluesy dominant 7th chord or a tense melody, listen closely for the minor 7th at work! Understanding its sound and usage is key for mastering intervals and music composition.