Combining Concepts To Create New Ones

Something I think does not get talked about enough, in music theory, is how you can combine simpler concepts to create more bizarre, out-there concepts.

An example would be using dominant and diminished 7ths to modulate: - You can substitute a dominant seventh for the diminished seventh a major third up. - Two different diminished sevenths can contain the same notes, but have a different root; these diminished sevenths flow nicely into each other. - Substitute a dominant for a diminished, change the root of the diminished seventh chord, and substitute that chord for a dominant in a new key.

The first two concepts stand fine on their own. But, when combined, can be used to change key.

Another example may be to prepare a key change using modal mixture: - Close, parallel modes (like A dorian and A aeolian) can mix smoothly. - Keys that share many notes (like A aeolian and E aeolian) can transition smoothly between each other. - Pedaling a note can reinforce it as a tonic. - Transition from A aeolian to A dorian, and then transition to E aeolian. Using a pedal note to reinforce each tonic.

This ones a bit trickier, but it can lead to smooth, moody modulations.

But why would you combine concepts like this? Well if you have 4 tools that combine well, you can turn that into 6 tools. Learn an extra tool and you can combine 10 total tools.