Music Theory for the 21st-Century Classroom

Although we will discuss mode mixture and the Mixolydian mode later, the ubiquity of the subtonic chord (♭$\text{VII}$) in rock and popular music makes it important to discuss here.

The ♭$\text{VII}$ chord can precede tonic, dominant, and pre-dominant chords, which means it can substitute for any function except tonic.

Notice also that movement from $\text{IV}$–$\text{I}$ (from the plagal cadence) is common in the following examples from popular music.

Here are examples ending with ♭$\text{VII}$–$\text{IV}$–$\text{I}$, where $\text{IV}$ progresses to $\text{I}$ (a plagal cadence) and is preceded by ♭$\text{VII}$.

Consider the following questions: When a phrase ends on the $\text{IV}$ chord, does it have dominant function (i.e, is it a half cadence)? Does $\text{IV}$ have dominant function in popular music when it progresses to $\text{I}$? If so, does ♭$\text{VII}$ have pre-dominant function in the above progression?

Notice that ♭$\text{VII}$ begins the phrase in the following example, and proceeds to a $\text{IV}$–$\text{I}$ conclusion.

The following example has ♭$\text{VII}$ preceding and following the $\text{IV}$ chord. Does the ♭$\text{VII}$ chord have tonic prolongation as labeled, or is it “pre pre-dominant” in function?

Here is an example with ♭$\text{VII}$ cadencing to the $\text{I}$ chord in the first four bars then progressing to the $\text{vi}$ chord in a deceptive cadence in the second four bars.