If you are skipping the 7th chords because they confuse you then you are missing the opportunities of creating the most pleasing sounds that you can make on a guitar or any other instrument.
One of the main reasons the 7th chords are confusing is that there are several different versions of a seventh chord and all have different notes. But if you take a break and seek out the meaning of the notes, then everything will make sense and it won’t be confusing anymore.
So, In this lesson I will help in making you familiar with the most commonly used seventh variations and for that I will be using the key of C.
The Major 7 ( C Maj 7 ) On Guitar
This is the simplest position of the 7th chord and it is in the key of C. The formula behind playing a seventh chord is to play a major chord and add the 7th note of the major scale to it. For example, the C Major chord formula is C, E, and G. So, when we add the 7th note of C Major scale i.e, B to the C major chord, it becomes a C Maj 7 chord. So, the C Maj 7 formula becomes C, E, G, and B.
Dominant 7 ( C 7 on Guitar )
This is the most popularly used 7th chord which is used in genres like blues and pop-rock. The process of creating a dominant seventh chord is quite simple. Simply take the major 7th chord and flatten down the 7th note by a half step. For example, our C major 7th formula is C, E, G, and B, so now the dominant 7th ( C7 ) chord becomes C, E, G, and Bb.
Minor 7 ( C m 7 in Guitar )
If you are thinking that only Major chords have sevenths then you need to think a little more because the minor has it too. The formula is the same as the major 7th. Like we add the 7th note in a major chord to make it Major 7 similarly by adding the 7th note of a minor scale to a minor chord it becomes Minor 7.
For example, the C minor 7 chord formula is C, Eb, G, and B. By adding the seventh note of its minor scale which is Bb, it becomes C minor 7. Here Eb is the minor third of C.
Diminished 7 ( C dim 7 )
It is super easy to make the diminished 7 chords. All we have to do is put the minor thirds on the top of each other. So, the minor third above C is Eb, the minor third above Eb is Gb, and the minor third above Gb is A. So, in the key of C the diminished 7 chord formula will look like C, Eb, Gb, and A.
Minor 7 flat 5 or half-diminished ( C m7b5 )
To create this chord we can start by taking a minor 7th chord and then lowering ( flattening ) the 5th note by half step. For example, the C m 7 formula is C, Eb, G, and Bb. By flattening the fifth note which is G by half step, it becomes Gb. So, the C minor 7 flat 5 chord formula will look like C, Eb, Gb, Bb.
I hope I did justice in making you understand the principle behind seventh chords and how actually they are build. I got inspired by few articles on the internet to write this. Now that you have it, you can start implementing in your playing and I guarantee that it will be exciting.