In the world of music theory, understanding chord inversions and figured bass is absolutely essential, especially if you’re preparing for the AP Music Theory exam. These concepts are the building blocks of harmonic analysis and composition. In this post, we’ll walk you through everything you need to know: from the basics to deeper insights — with plenty of examples.
What are Chord Inversions?
A chord inversion occurs when the notes of a chord are rearranged so that a note other than the root is in the bass (lowest) position.
- Root position: The root of the chord is in the bass.
- First inversion: The third of the chord is in the bass.
- Second inversion: The fifth of the chord is in the bass.
- (For seventh chords:)
- Third inversion: The seventh is in the bass.
Why Learn Inversions?
- They create smoother voice leading.
- They add harmonic variety.
- They are crucial for harmonic analysis, cadences, and progressions.
| Chord Type | Bass Note | Inversion |
|---|---|---|
| C-E-G (C Major) | C | Root position |
| C-E-G | E | 1st inversion |
| C-E-G | G | 2nd inversion |
Introduction to Figured Bass
Figured bass (also called thoroughbass) is a musical notation system from the Baroque era. It indicates intervals above a written bass note, allowing performers to improvise chords.
Instead of writing full chords, composers would write a single bass line with small numbers (figures) underneath it. These numbers tell the player what intervals to add above the bass note to create a full harmony.
Example:
- A bass note with a “6” under it means you should add a note a sixth above, along with a third above — making a first-inversion triad.
Common Figured Bass Symbols for Triads
| Figured Bass | Meaning | Inversion |
|---|---|---|
| No numbers or “5/3” | Root position triad | Root position |
| 6 or 6/3 | First inversion triad | First inversion |
| 6/4 | Second inversion triad | Second inversion |
Common Figured Bass Symbols for Seventh Chords
| Figured Bass | Meaning | Inversion |
|---|---|---|
| 7 | Root position seventh chord | Root position |
| 6/5 | First inversion seventh chord | First inversion |
| 4/3 | Second inversion seventh chord | Second inversion |
| 4/2 (or 2) | Third inversion seventh chord | Third inversion |
How to Read Figured Bass
- Look at the bass note.
- Read the numbers to know what intervals to add.
- Fill in the notes above the bass according to the indicated intervals.
- Understand that the numbers are often shorthand — for instance, “6” implies a 6 and a 3 above the bass.
Example:
If you see an “E” in the bass with a “6” figure:
- E is the bass note.
- Add a third above (G) and a sixth above (C).
- The resulting chord is C major in first inversion (C-E-G).
Key Tips for AP Music Theory Students
- Memorize inversion patterns for triads and seventh chords.
- Practice realizing figured bass both harmonically (chord voicing) and melodically (voice leading).
- Watch for cadential 6/4 chords (they are special second-inversion chords).
- Understand how inversions affect Roman numeral analysis.
Why Chord Inversions and Figured Bass Matter
In the AP Music Theory exam, you’ll be tested on your ability to:
- Identify inversions by ear and sight.
- Write and realize figured bass.
- Understand their use in harmonic progressions and cadences.
A strong grasp of these concepts will not only boost your exam score but also make you a much more skilled musician, composer, or arranger.
Conclusion
Mastering chord inversions and figured bass is not just about passing the AP Music Theory exam — it’s about understanding the language of music itself. Take time to practice different inversions, realize figured bass progressions, and apply them in your compositions. With dedication, you’ll soon be thinking and hearing music on a much deeper level.
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