4 for IV, Part II: IV Chords & Tonal Ambiguity/Modulation

In Part I of this series, I examined the secondary plagal progression, which is a unique way in which rock/pop composers have extended the established sound of a IV-I plagal progression. Another common technique that demonstrates the evolution of the IV chord is the incorporation of tonal instability through its presence in a harmonic progression. Generally, rock/pop music is not lacking for a tonal/modal center. However, some songs use the comforting and predictable sound of a plagal progression to introduce either tonal ambiguity or a full-fledged modulation.   Green Day, “Warning”   Despite its lack of overdriven electric guitars, “Warning” is very much a prototypical Green Day song because it only uses three different chords the whole way through. Yet these three chords (one of which is a secondary plagal chord) present an unexpected analytical challenge that lends a subtle sense of ambiguity to the song’s tonality.   Except for the song’s bridge and start of its third verse (which both simply vamp an A chord), the entire song uses the following progression. For those not familiar with my notation, vertical lines indicate barlines, diagonal slashes between chords indicate multiple chords in the same measure, and lead-sheet symbols and Roman more »


4 for IV, Part I: Secondary Plagal Progressions

Before beginning my analysis for this project, I didn’t really know much about The Go-Go’s. I knew they were an all female band from the 80’s that had some cheesy hits, but that was about the extent of it.   Knowledge and perspective can be funny things. I’m not ready to anoint them as successors to The Beatles or anything, but knowing what I do now, I certainly have a much greater respect for their musicianship.   As the introduction to this series discussed, the IV chord has a crucial role in rock/pop music harmonic progressions, particularly in relation to how the harmony is used in concert music. Songwriters have grown to love the chord so much that they have pioneered ways of using it that have given its function fresh vitality and have helped to further distinguish this genre from others.   Understanding Secondary Plagal Function   Perhaps the most common of these unique applications of the IV chord (and, specifically, its plagal function) is the use of secondary plagal progressions. A plagal progression results from a chord built on the fourth degree of the scale resolving directly to the tonic chord, with the root of the former being more »