How to make a minor four chord:
Identify what key your song is in
Follow the major scale up from the root to the fourth degree
Build a minor chord with the fourth degree as the root note
Where to use a minor four chord:
This chord works well when placed preceding your tonic chord (the chord that is at the key center of your song—if your song is in E major, then E major is your tonic chord). The minor four chord works well in this position because it draws the listener back to your key center.
To explain this with music theory, the minor four falls under the category of functional chord substitutions, meaning that it stands in for another chord that has the same function. In this case, the minor four has the same function as a dominant V chord, which means it generally leads the listener back to tonic.
But remember, there are no rules—try it out and see where your ears take you!
2. The flat seven (bVII)
The flat seven is another familiar sound in pop music. From top 40 to punk rock, it has its place as one of the most common chromatic chords used by songwriters. The flat seven takes some of the sound of the Mixolydian mode and brings it to the common major scale. It can be hard to describe the sound of a flat seven in words, but it certainly changes up the feel.
Let’s give it a listen! Here’s a flat seven in “The Less I Know The Better” by Tame Impala. The flat seven can be heard clearly as the third chord in the song’s B-section (the first flat seven appears at exactly 1:11). This contrasts the feel of the previous section that uses only diatonic chords.