7th chords allow you to add a new dimension to your harmony in your songwriting. In addition, they also create a function: Dominant movement in music.
What’s a Dominant Chord mean?
Well, the dominant note in a kay is the Fifth (5th) scale degree. So for example, if I’m in the key of C, then my dominant chord is G. The thing is, that a dominant chord has a seventh note of the scale in it. So the fifth of C would actually be played as a G7 chord = The harmony in this chord is ‘G-B-D-F’.
Seventh Chords have a Flattened seventh in them. Understand that, and notice how the F in the G7 chord is F natural – NOT F#
To learn more about Seventh Chords check out my Seventh Chord ‘FAQ’s’.