The dominant 7th chord is really important for blues and country guitar music. The chord is a four note chord. This means that it is a tetra chord. It is treated more like a minor, but the base line is treated more like a major.
Dominant 7th chord is used a lot in country music. It is not as uplifting as the major chord (except for the major 7th). In the blues however, it is used as a substitute for minor chords. It gives a harder sound compared to the minors, which makes it more fitting for the blues.
This type of chord is a perfect choice for blues. There are lots of chords, like the G7, which would be great for the blues. A variety of sevenths may be added to a variety of triads, resulting in many different types of seventh chords. They are formally named according to the type of triad or the type of seventh. For example: a major triad or a minor seventh is referred to as major/minor seventh.
The dominant 7th chord is the most common type of of 7th chord you will encounter in music. There are also other 7th chords with the same characteristics of the dominant 7th chord, like the knife and the knife augmented. Practice these chords (Gmin7, G7, Gmaj7, Cmin7, F7) with any strumming pattern you feel comfortable with. In time, you’ll be a master of the dominant 7th chord.
The Dominant 7th Chord:
Watch the video on the dominant 7th chord on you tube