We have looked at how chords are made by ‘stacking thirds’ but we have only done it for 3 notes; what if we add another third on top?
That’s when we get 7th chords. These chords have a Jazzy, Soulful sound to them and sound a little more exciting than your normal triadic chords. This is because that extra note makes the chord a little more complex and sounds great.
There are 3 types of 7th chords and each of them has a unique sound.
The first is the major 7th chord. This has quite a wholesome sound that is sweet and relaxing. Here is a set of major 7th chords played together so you can hear the sound:
[insert sound of major 7th chord progressions]
The relaxing chord is made with the intervals R - M3 - P5 - M7. The commonly used shapes look like this:
[insert major 7th shapes]
The second one is the minor 7th chord, now this one has a sadder sound but is also quite cool. This chord was and is still used a lot in Rhythm and Blues, Blues, Rock, and Pop music. The minor 7th interval doesn’t feel like it has to resolve so it gives us a sound that has a bit of tension, but not enough to make the chord sound bad.
[insert sound of a minor 7th chord progression]
The minor 7th chord structure is R - m3 P5 - m7. The common shapes look like this:
[insert minor 7th chord shapes]
Lastly, we have the dominant 7th chords. These are special chords as there are only a few chords that give a satisfying sound when these resolve, and this is one of them. A dominant 7th chord has a major 3rd and a minor 7th together. Because the major and minor are together, it creates a to of tension and feels like it has to resolve soon otherwise it’s going to blow up! Here is the sound of a dominant 7th chord:
[insert sound of a dominant 7th chord]
As you can see, it sounds like it desperately wants to resolve to another chord. We can use this tension to build suspense and relieve the listener so they enjoy it a little more, like so:
[insert sound clip of dominant 7th chords not resolving then resolving on the final one]
The structure of the dominant 7th chord is R - M3 - P5 - m7 and the chord shapes look like this: