The Heart Of Dominant Function
 
Dominant function drives chord progressions forward, but what drives dominant function? Well, at its heart, the answer lies in two specific notes that combine to form the most powerful directional sound in Western music: the tritone. The tritone's instability creates a powerful need to resolve, and its flexibility allows for all kinds of weird and wonderful dominant function chords. It's the most important sound in functional harmony, and it's the basis of a lot of music theory. So how is it used, and what does it let us do? Well, lots of ways and lots of things, respectively!