Last time I wrote about fitting chords to a melody. In this blog we’ll revise inversions and talk about figured bass.
You can invert a melody by reversing the direction of the pitches and whilst this is a useful composition tool the inversion I’m going to explain here is where you change the order of the notes within a chord. With a triad there are two possible inversions you can use to make chordal accompaniments more interesting or easier to get to. This gives you three ways of playing a chord!
In each of the examples I will show you the note positions and the different ways you can show the inversion using numbers, roman numerals, and chord symbols. You wouldn’t normally have Roman numerals & Figured Bass or indeed chords. It would be one or the other.
One very important thing to remember...when dealing with inversions of triads you are only changing the order of the notes - you are not changing the pitches!
This is where the ROOT note, ie the name of the chord, is at the bottom of the triad. The order of the notes from bottom to top is 1-3-5. I’ve put the figured bass in this example, though you wouldn’t normally get it here. Sometimes you may see 5/3 - this indicates a root position triad. It means the top note is five away from the root and the middle note is three.
The root jumps up an octave leaving two notes close together at the bottom. The order of the notes from bottom to top is 3-5-1. In figured bass it would just be a number 6. When you see 6/3 after a chord that tells you it's a first inversion. It means the top note is six away from the low note and the middle one is a third.
Note 3 jumps up the octave leaving note 5 at the bottom with 3-1 on the top. The order of the notes from bottom to top is 5-1-3. In figured bass it would also be written as it is here. Sometimes you may see 6/4 after a chord which is yet another way of telling you you're in second inversion. It means the top note is six away from the bottom one and the middle note is four from the bottom.
You can only have a third inversion when there is a fourth note. In this instance the seventh note stays on the bottom and the 1-3-5 are in order above it. The order of the notes from bottom to top is 7-1-3-5
What Do Those Numbers Mean?
The numbers refer to a thing called Figured Bass. This was largely used in Baroque music in the Basso Continuo (continuous bass part), but it does appear in some classical music too. The continuo will be played by more than one instrument (Double Bass, Cello, Harpsichord, Organ, Harp, Lute, Bassoon) but it is essential that at least one of the instruments can play chords and I’ll explain why in the next paragraph. The usual combination for basso continuo is harpsichord and cello, but it certainly isn’t limited to this.
Continuo parts are written with just the bass notes on the stave. Under the notes there would sometimes be numbers and these numbers would tell the player what chords they needed to play. Then, based on the numbers the player (who can play chords) would improvise an accompaniment using the notes of the chords given. Non-chord playing instruments would simply play the basso continuo line. This improvisation was called a realization.
If, in figured bass, there is no number then the chords will be played in ROOT POSITION. That is to say 1-3-5. The 6 means that the bass note is the 3 of the triad and the root (1) is a sixth above that 3 (the low note). This is first inversion. The 4 (under the 6) tells you that the chord is in second inversion. The low note is the 5 of the triad and the root (1) is a fourth above that and the 3 is a sixth above 5. A 7 under a note means play the chord in ROOT POSITION and add the 7th note.
As with all notes you can also add sharps or flats to figured bass. If you have a sharp sign next to a number, you raise that note by a semitone. This instruction can also be shown with a plus sign (+) or a slash going through the number (6) (though it’s often down with a slight downward slope). A flat symbol next to the number will tell you to lower that note by a semitone and a natural tells you to use the natural of that note regardless of its position in the key signature. If you see a symbol on its own with no number it is referring to the 3 every time.
Moving Between Chords
I hinted at this in my description of what inversions are. When you’re playing chords one after another they want to sound smooth. You don’t want any massive jumps from chord to chord - unless it’s for dramatic effect! If you play a keyboard instrument, or guitar, you may know about the importance of being able to move to and from each chord with ease. Knowing how inversions work can really help with this.
The best way to do this is to look for the common notes between each chord. In this example say you want to go from C to G. Just jumping down from one triad to the next is going to sound clunky. But if you look at the common note(s) you can see that both chords use G. If you keep the G where it is and just drop the other two notes to what is needed for the new triad, the move is a lot smoother and the music will flow better.
A Final Thought
This has been a huge topic and in the next blog I’ll write about the different ways you can execute the playing of your chords. Take your time to absorb everything that you’ve read over this blog and the previous two.
Sometimes you may need to work out what a chord is either from a group of melody notes, or a triad in one of its inversions. This is where what we covered in Chords 1 will come in very useful because you’ll be able to look at the key and identify each individual note and use that information to identify the root portion chord.
If you can remember line-line-line or space-space-space (ie the notes are all a third apart) that’ll give you your root position so you can then identify the chord.