Figure Bass, Slash Chords and Roman Numerals

Goal

Understand figure bass and roman numerals, how they are labeled and why. This is a bare bones introduction to figure bass just for the understanding of how to write inversion with roman numerals.

Harmonic Analysis

We have a system for giving the position of a chord in a scale however we haven't explicitly gone over it. We cover the details of this system and will extend it to cover inversions as well. Such a system can be used to analyze music and come up with theories on why it sounds the way it does.

First we use roman numerals, we do this because we can use upper and lower case. Upper case for major chords and lower case for minor chords. For diminished chords we use the lower case along with a °. For augmented chords we use a uppercase with a +.

This covered the basic triads in root position but it says nothing about the Inversion, this is where we introduce figure bass.

Roman Numerals

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Figure Bass

Figure Bass is a system based on the bass note. Traditionally it was a system meant for improvisation, but we use chord symbols now. Instead it has found a home in harmonic analysis.

The way it works is simple, say we have the following triad:

Roman Numerals

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Here the C is the bass note. We then count up the interval number to the next note in the chord. We see it is a 3. We also count from the bass note to the next note which is 5. This is obvious because 3 and 5 make the root position triad. Assuming this is a 1 chord we would write the figure bass as:

Roman Numerals

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This says we are playing the 1 chord, it's major because it has an uppercase roman numerals and we need to include the 3rd above the note and the 5th above the note. We know it must be a major third and a perfect 5th because it is a major chord.

In this way we can analyze music. What this way of anaylizing does is it gets rid of the specific notes and instead focuses on the relationship between notes which is much more telling on why music sounds the way it does.

Since all root chords will have a 3 and a 5 we do not write this, instead it is assumed, otherwise we would have 3 and 5's all over the place not really telling us anything not already apparent, therefore we could simply write:

Roman Numerals

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For example a 2 chord of C major would be analyzed as:

Roman Numerals

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First Inversion

Consider a chord in the first inversion.

Roman Numerals

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Here we see there is now a different size space. Looking at the chord we have E, G, and C. If we count from E (the bass note) to G (the 5th) we count 3. Counting from the bass note E to the root note C we count 6. Therefore the figure bass would have:

Roman Numerals

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Recall however that 3 is considered trivial because it is assumed due to how common it is. Therefore we only write the 6. This leads us to this result:

Roman Numerals

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Hence whenever a 6 means we know the chord is in first inversion.

Second Inversion

Consider now a C major second inversion triad:

Roman Numerals

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In this case we have a G, E and a C. Counting from G to E we have a 4 and from G to C we have 6. So the analysis would be:

Roman Numerals

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In this case no trivial intervals are used so the 4 and 6 are required.

That’s all we need for figure bass for triads! It can go much further but for our purposes this will be enough. Now we can specify root position, first inversion, second inversion, and alterations.

Not done! More is on the way

Chromatic Analysis

In some cases chromatic analysis will be required. Often there are multiple ways to do this and it is a bit of an art picking one that explains it the most elegantly.

You can write sharp or flat next to the figure bass to show any chromatic deviation.

Practice

Reveal Answer

Slash Chords

Chord symbols by themselves do not state what note is in the bass. For this reason slash chords exist. For example:

Chord symbols by themselves do not state what note is in the bass. For this reason slash chords exist. For example:

Slash Chords

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Here is C/E, meaning a C major chord with an E in the bass. It is the same thing as a I6 only it specifies the notes. When using chord symbols this is how we specify inversions.

Example 2

Slash Chords

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Here is a Gm/Bb meaning a G minor triad with a Bb in the bass.

Practice

Reveal Answer

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