Music is mostly made up of chords. Chords are the most basic aspect of harmony and one of the most fundamental parts of music in general! To find out more about what harmony is, make sure to click here. There are many different types of chord such as the major chord, minor chord, seventh and more. But in this post we will talk specifically about a special kind of chord called the altered chord. So let’s look at what altered chords are!
What are Altered chords?
Altered chords are simply diatonic triads or seventh chords where one of the pitches are raised or lowered by a semitone (half step). A diatonic triad simply means a triad that contains notes that are within a given scale/key. Altered chords therefore are simply chords where one or more of the notes in the chord have been chromatically altered.
Let’s take a look at Chord V in C major. Remember we label chords using Roman numerals, to find out more make sure to check our our guide to labelling chords.
This chord has the notes G, B, D. Remember the root of this chord will be G because G is the 5th note of C major and that is what makes this chord chord V.
If we alter the B to Bb, so we have the chord G, Bb, D. Or if we alter the D to D# so we have the chord G, B, D# we have now created two altered chords! In its broadest definition, if the note you alter is not in the diatonic key, then the chord can be considered altered!
Remember a diatonic key is simply a scale from the circle of fifths that has not been altered in anyway. To learn more about our diatonic scales then make sure to click here to read more about the circle of fifths.
Why do we use altered chords?
Altered chords can add a lot more color to your pieces but they can also be used as leading tones to emphasize the diatonic neighbors. By doing these chromatic alterations to the notes you can create a pull to certain notes. Remember, music is always trying to find it’s home key or root note (this simply means chord I in any given key!).
One of the most common altered chords in music is the augmented chord. An augmented chord is simply when the fifth of the major triad is raised or ‘augmented’ by a half step (semitone). We call this chord the augmented fifth. By augmenting the 5th we end up with a triad that has two major thirds.
What are the most common notes to alter?
The most common notes to alter in an altered chord are the 5th and 9th degrees. This is especially true in the case of a dominant seventh chord which is a major triad with a flattened (minor) seventh above. If you need to know what this means, head over to our guide to seventh chords. For example, the dominant seventh chord of C major has the notes G, B, D, F. The reason this chord starts on a G is because G is the dominant note (fifth note) of C major.
Notice how the G – F (the root of the triad to the seventh of the triad) is a minor seventh. i.e. a flattened seventh. You would label this chord as G7 to indicate that it will be a minor seventh (flattened seventh)above the root.
So if we have C7 the notes will be C E G Bb. C-Bb is the interval of a minor seventh (flattened seventh).
If we add the 9th we will then have the notes C E G Bb D.
The altered version of this chord would simply mean we raise (sharpen) or lower (flatten) the 5th or 9th degrees. Our options for this chord would then become:
C7b5 – C E Gb Bb D
C7#5 – C E G# Bb D
C7b9 – C E G Bb Db
C7#9 – C E G Bb D#
These chords are often called and labelled as Alt chords.
Alt chords are used in jazz music theory. Instead of using the notations we saw above, the dominant chord will simply be labelled C7alt. This means that the player can decide what configuration to play!
An Alt chord will have the following notes:
- Major 3rd
- b5 or #5
- Minor seventh
- b9 or #9
You can then also have a raised 15th but this is only used when the 9th of the chord is a natural. This is because the 15th functions as a minor 9th creating a major 7th interval with the natural 9th assuming that the chord is in root position.
In jazz harmony, chromatic alteration is either the addition of notes not in the scale or expansion of a progression by adding extra non diatonic chords.
common altered chords
As we have seen, an altered chord contains one or more altered (changed) tones. If we use a seventh chord, we will have four possibilities because there are four notes. Let’s have a quick look at the different possibilities when we use a seventh chord:
V+7 (Augmented 5th with added 7th)
We saw this chord earlier in the post. This simply means an augmented fifth chord, meaning that the 5th of the chord is raised. The seventh simply tells us to add the flattened 7th above.
V7b5 (Dominant 7th chord will flattened 5th)
This chord is not used as often as the V+7. Notice that the b5 of chord five is the same as b9 of the key, so this tone will have a very strong pull to the root.
If we were in C major, this chord would be G B Db F
9 notes up from C is D, and a b9 will be Db (same as the b5 in this chord!)
Vm (Minor Dominant chord)
This chord is extremely common and simply involves altering the third. It involves changing the major third into a minor third. It can give quite an unexpected sound. Although this on the face of it seems very basic, the simple move from a major 3rd to a minor 3rd is an alteration and therefore an altered chord!
A very noticeable place to see this is in Coldplay’s Clocks intro.
Minor Dominant seventh chord with flattened 5th
This chord has an interesting sound and can be used in place of the V7 but it can also sound a bit like the chord II in a II-V-I progression in a minor key.
If we look at this in the key of C major we will have the notes:
G Bb Db F
Dominant 7th chord with suspended 4th
To learn more about suspended chords make sure to click here, but this essentially means that we are raising the 3rd of the chord to the 4th degree.
In the key of C major this would be the notes:
G C D F (the normally V7 chord in C major would be G B D F)
Dominant 7th chord with major 7th
This chord involves altering the 7th. A normal V7 chord has a flattened (minor) seventh and so in a Vmaj7 we are raising this 7th by a semitone.
The notes in this would be G B D F#
Diminished 7th chord from an altered root note
In this chord you are altering the root. By altering the root of the chord you are creating a very strong pull to the sixth note of the scale.
In C major the notes would be:
G# B D F
Remember the small circle next to the V simply means that the chord includes a diminished 5th interval and G#-D is a diminished 5th!
The G# is only a half step (semitone) move away from the 6th note of C major which is an A.
These alterations can then continue up into the chord extensions, meaning that you can alter the 9th, 11th, 13th, 15th and beyond!
Other examples of altered chords
The two most common chord types that have non diatonic notes (altered!) are
- the borrowed chord
- secondary dominant chord
A borrowed chord is simply a chord in a specific key that borrows notes from either the parallel major or minor keys.
So for example, if we are in the key of C major, the parallel minor key will be C natural minor. If a diatonic chord from C major was now to borrow a note from the parallel minor key, we will now have a borrowed chord.
The diatonic chords in C major are as follows:
Now if we write out the chords in C natural minor we will create a completely different set of chords.
If you borrow one of these chords from the C minor selection you have now used a borrowed chord. Remember you will only use a borrowed chord as a passing chord otherwise you are in danger of changing the entire key of a piece!
Secondary Dominant Chord
A secondary dominant chord is a dominant chord (a 7th chord with a major third and a minor seventh) that resolves to any note besides the tonic. To make it simpler, a secondary dominant is a chord that has a dominant function but is not the dominant chord of the tonic key.
So for example, in C major, the dominant chord would be G7. If whilst in this key we decide to use a different dominant chord such as A7 this would be called a secondary dominant chord. A7 wants to resolve to a D major chord and not the tonic of C major.
In conclusion, the term altered chord simply means to raise or lower one or more notes in a chord. Rather than just using notes stated in a particular key, an altered chord will use extra notes not within that diatonic key.
Altered chords should be used in isolation and not throughout an entire chord progression. Altered chords are particularly useful at adding extra color when writing music. The most common chord altered chords are the altered dominant chord and the altered seventh chord, although technically by it’s definition any chord that has notes that are chromatically raised can be considered an altered chord.