This is more detailed lesson on chords, so before you read ahead, make sure you understand how chords are made and understand why intervals are important. If you need a refresher, just click the links!
All caught up with them? Great! Lets get stuck in!
Up to now we have been looking at triadic chords which are made up of 3 notes. In our case, the chords are usually Major and Minor Chords, which have the intervallic pattern of Root - Major/Minor 3rd - and a Perfect 5th. An extended chord adds another interval on the end of that, making it a tetrad, but this name isn't commonly used, as extended chords are usually called by their extension. It is implied that the Root, Major/Minor 3rd, and Perfect 5th are being played too.
We'll look at the most common extended chord: the 7th. This note is used a lot in Blues, Rock, Jazz, Pop, Soul, and many other genres. It adds another flavour to the sound, making it stand out and more exciting than triadic chords. There are 3 different types of 7th chords you can play.
Major 7th (Root - Major 3rd - Perfect 5th - Major 7th): This has a happy sound to it and is used a lot in Soul and Jazz. You can see from it's intervals that it is a Major chord with a Major 7th on the end. This is the magic note that gives it that soulful sound!
[insert sound clip of the chord]
Minor 7th (Root - Minor 3rd - Perfect 5th - Minor 7th): Compared to the Major 7th, this has a darker sound, but has a cool feel to it. We have actually heard this sound in a lot of Rock and Pop tracks which is why most of us usually think of it as having a cool sound!
[Insert sound clip of the chord]
Dominant 7th (Root - Major 3rd - Perfect 5th - Minor 7th): This is a special chord, as it doesn't sound happy or dark, it just sounds... confused. Because of the Major 3rd and the Minor 7th, there is a bit of tension in the chord an it wants to resolve.
[Insert sound clip of the chord]
There are other extensions and the follow very similar rules to the 7th. The other extensions are usually an octave above the intervals we have already, so if we take a Major 2nd interval and bump it up an octave (12 semi-tones) then this will take us to a Major 9th. This is usually used on the 2nd, 4th, and 6th. If we didn't add the octave on there, then the sound would be quite dissonant and wouldn't sound as good and as spacious as it could do.
Major/Minor 9th - 2nd + octave
Major/Minor 11th - 4th + octave
Major/Minor 13th - 6th + octave
It's also important to know that if you play an extended chord, it's chord will include the last extension also. So if we look at a Major 11th Chord, it will have the Major 7th and the Major 9th before it (unless the chord says otherwise). So a Major 11th would be Root - Major 3rd - Perfect 5th - Major 7th - Major 9th, Major 11th
These can also be major or minor. We would do the same thing we did with the major and minor 7th chords; change the 3rd to match the same as the 9th. So if we have a Major 9th chord, then we would have Root - Major 3rd - Perfect 5th - Major 7th - Major 9th. If it was Minor we would have Root - Minor 3rd - Perfect 5th - Minor 7th - Minor 9th.
And if that wasn't confusing enough, we can ALSO have mixed extended chords like MinorMajor9 where the Triad would be Minor and the extensions would be Major. The first tonality is for the triad, and the second part of for the extensions. In this case, it would be Root - Minor 3rd - Perfect 5th - Major 7th - Major 9th.