Learning figured bass may seem complex at first, but once you grasp its concepts it can help you understand chord progressions on a keyboard or when analyzing music.
Chords containing a root note in the bass have four potential inversions; numbers stacked together indicate which inversion it’s currently in as well as its quality.
First Inversion
Figured bass numbers serve to denote which intervals should be played above a chord’s bass note. For instance, if your chord contains three thirds as its bass note, and the third note has been assigned the number 3, then figured bass numbers indicate you should play two second notes above it and four fourth notes above that.
Roman numerals are used to identify particular chord types; however, figured bass numbers simply provide information regarding intervals which should be played above any particular bass note. They do not show whether the chord is major, minor, perfect or diminished as this will depend on its key signature and other accidentals.
Learning figured bass may seem challenging at first, but with time and practice you will develop the skills to recognize chord inversions based on its number – this allows you to quickly identify bass notes for chord progressions and play them without writing out all of their upper voices separately.
Second Inversion
The second inversion of a seventh chord features identical intervals to its initial form, yet with lower numbers. For example, a C major seventh chord in second inversion would feature 6/5 (meaning that “1” lies a sixth above “3” in bass position while “7” sits one fifth above it).
Be familiar with the inversion numbers associated with triads and sevenths; any variation that doesn’t align with them indicates non-chord tones present.
When this occurs, you can still realize the chord by realizing the closed position B-D-F-G of the second inversion and inverting that to get figures 3/5/6; similar to how one might realize a seventh chord inversion for its closed position. Please be aware there may be exceptions but they won’t require your attention at this time.
Third Inversion
A third inversion of a seventh chord involves adding intervals that span second, fourth, and sixth above its bass note – usually denoted by 6/4/2 or sometimes just 4/2 in bass numbers.
Underneath bass notes, numbers represent intervals above them that should be played. So if the bass note is C and 7/5/3 is written below it, that means there should be one note a fifth above it which would be G.
Realization is the process of turning a figured bass into a chord, whether by adding notes above it to complete it (such as A, F# or C#) and turning that bass into an actual chord. Chords can be realized from any source – including chord symbols and triads. To create seventh chords such as Gm7s you need to start by realizing their root position chord then invert it. To realize a Gm7 chord this means adding A F and C# above its bass in addition to add all three notes above its base – for example Gm7 = Gm7 + inverted root position chord + inverted root position = Gm7 + inversion = Gm7 chord
Fourth Inversion
Seventh chords can span more than one octave, so it is crucial that one can identify inversions using their numbering system. For example, Cmaj7 chord in bass would be written with symbol 43 indicating its first inversion since its root starts from third rather than first position.
At first, it may be challenging to recognize inversions by ear; with practice you’ll quickly develop your ability to interpret them quickly. The key is familiarizing yourself with figured bass numbers for triads and practice recognizing their intervals. Also if a combination does not appear similar to what was listed above it usually indicates non-chord tones present – something we will cover more in depth later. For now focus on identifying the root of each chord as this will enable you to figure out the Roman numeral and subsequent notes that follow it.