Figured Bass Symbols

Figured bass is a notation convention used to specify chord inversion, in which Arabic numerals (numbers) are written (placed vertically, in descending numerical order) below the bass note of each chord in a harmonic progression, expressing the intervals resulting from the voices above it.

For example, in the root-position triad above C-E-G written for 4 parts, the intervals above bass note C are a 3rd (E) and a 5^th (G), giving the figures 5-3.

If this triad were inverted (e.g., E-G-C), the figures 6-3 would apply, due to the intervals of third (G) and sixth (C) appearing above bass note E. This triad would be in 1^st inversion since the 3^rd of the chord is in the bass.

Certain arbitrary conventions of abbreviation (and sometimes non-abbreviation) exist in the use of figured bass. In chords whose bass notes appear without symbols, 5-3 position or root position is understood by default. So when there are no numbers associated with a Roman numeral, root position is assumed.

First-inversion triads ( 6-3 ) are customarily abbreviated as just 6, i.e., presence of the 3rd is understood. Second-inversion triads ( 6-4 ) are not abbreviated. So the 6 and 4 must be present.

Figured bass numerals express distinct intervals in a chord only as they relate to the bass voice. They make no reference to the key of the progression. They do not express intervals between pairs of upper voices themselves (for example, in a C-E-G triad, figured bass is unconcerned with the interval relationship E-G). However, the figures are often used on their own (without the bass) in music theory simply to specify a chord's inversion. This is the basis for the terms given above such as " chord"; similarly, in harmonic analysis, the term I⁶ refers to a tonic triad in first inversion.

Inversion numbers are used in conjunction with the Roman numerals so a chord can be analyzed as to its inversion as well as to which note the chord is built upon, i.e. in the key of C major a CEG chord with the 3^rd in the bass would be analyzed as a I6 chord. The chord is built on the 1^st scale degree of C major and the 3^rd of the chord is in the bass note.

Below are some examples of root position, 1^st inversion and 2^nd inversion triads with their Roman numeral and inversion number analysis.

In the activity below, determine each figured bass symbol as being either: 1) Root Position, 2) 1^st Inversion or 3) 2nd Inversion

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