Lead-Sheet Symbols, Bass Position Symbols, and Roman Numerals
Lead-sheet symbols are a type of short-hand notation that tells the musician the root and type of chord. This system is not completely standardized in textbooks and published music, which means there are sometimes two or more accepted symbols that can represent a given chord. Lead-sheet symbols can be used to harmonize a melody. The usual custom is to place the lead-sheet symbol directly above the measures in a melody.
Lead-sheet symbols are a valuable tool in understanding and analyzing music. We will use the following lead-sheet symbols as the standard for our class.
Bass Position Symbols (Figured Bass Symbols)
Chords can appear in root position or in inversion. The lowest written note of a triad or seventh chord in root position or inversion is referred to as the bass. Root position chords feature the root as the lowest note. First inversion chords feature the third of the chord as the lowest note. Second inversion chords have the fifth of the chord as the lowest note. Seventh chords allow for a third inversion in which the seventh of the chord is the lowest or bass note.
Inversions are indicated using bass position symbols. During the Baroque period, Arabic numerals were added to bass lines to show the accompanying harmonies. Keyboard players in an ensemble would read from these “figured bass” parts and fill in the harmonies. This system of figured bass symbols is now used in music theory in a simplified form. These numbers indicate intervals above the lowest note in the texture, even if it is in treble clef. For the purposes of this chapter, we will normally assume these are simple intervals. In part-writing and analysis, however, these numbers often refer to compound intervals.
Various symbols may be combined with these bass position symbols to raise or lower a pitch. For example, a ♯ or + next to a numeral or a slash through a numeral indicates that you should raise that note by a half step. A ♭ symbol next to a number indicates that you should lower that note by a half step. The ♮ symbol can be used to raise or lower a pitch, depending on the key signature. An accidental floating by itself beneath the staff belongs to the note a third above the bass and can be used to raise or lower that note. If there are no modifying symbols next to a bass position symbol, you should use the notes found in the diatonic scale which are the accidentals found within the key signature.
The following examples show these concepts in practice.
Roman numerals have been used in the analysis of Western music for over two centuries. Roman numerals include a lot of information about chords, including root, bass position, type, and function. They are a valuable tool in understanding the harmonic element of music.
Roman Numerals in Music Theory:
- Uppercase Roman numeral = major Triad.
- Lowercase Roman numeral = minor triad.
- Uppercase Roman numeral with a “+” = augmented triad.
- Lowercase Roman numeral with a “o” = diminished triad.
- Uppercase Roman numeral with a “M7” = major seventh chord
- Uppercase Roman numeral with a “7” = major minor (dominant) seventh chord.
- Lowercase Roman numeral with a “7” = minor seventh chord.
- Lowercase Roman numeral with a “Ø7” = half-diminished seventh chord.
- Lowercase Roman numeral with a “o7” = diminished seventh chord.
Diatonic triads built on each scale degree in major mode. This example is in the key of C major.
Diatonic seventh chords built on each scale degree in major mode. This example is in the key of C major.
Because of the existence of harmonic and melodic minor scales, the situation in minor keys is more complicated. In minor keys, all the common triads and seventh chords are constructed using the natural minor form of the scale EXCEPT the V, V7, viio, and viio7. These utilize the leading tone or raised seventh scale degree found in the harmonic and melodic minor scales. The purpose of the harmonic minor scale is to allow the creation of the V and viio chords in minor. The third of a root position V or V7 chord will be the leading tone in the key. The leading tone will be the lowest note of a root position viio or viio7 chord.
Diatonic triads built on each scale degree in minor mode. This example is in the key of a minor. An asterisk (*) indicates the most used triads in minor keys.
Diatonic seventh chords built on each scale degree in minor mode. This example is in the key of a minor. An asterisk (*) indicates the most used seventh chords in minor keys.