29: Diatonic Function Analysis
Lesson 29: Diatonic Function AnalysisYou learned the diatonic chord functions—tonic, subdominant, and dominant—in Lesson 27: Tonic Function and Lesson 28: Subdominant & Dominant. Now, to help you use them, you should study them in real songs. This is called diatonic function analysis.
Let's do an example. Here's a short chord progression in the key of C major (it's actually a simplified phrase from Bob Dylan's Like A Rolling Stone):
First, add Roman numeral symbols (from Lesson 26: Using Diatonics):
Next, we'll add diatonic function symbols. We'll use these symbols:
Here's the example with the diatonic functions added:
The diatonic functions have different tension levels, which means how at rest, or not at rest, that function feels. The tension levels range from the no-tension level, tonic (T), which sounds at rest, to the highest tension level, dominant (D), which "really wants to" return to the tonic. The way a chord progression moves between different tension levels creates that progression's tension story. Here's our example again, displayed as a tension-level graph so you can see the tension story's shape:
Following the Roman symbols above from left to right, we can see that this example's basic tension story is:
This particular story/shape is very, very common, but there are lots of variations and alternatives. To develop a feel for the effects of different tension stories, you should add diatonic function analysis to your Things to Practice list (Lesson 2: Teaching Yourself); make tension-level graphs for lots of different songs, make up tension stories from the graphs, and decide for yourself what you think the musical effects of different tension stories are.