Building off of this to talk about functional harmony (I recommend a book called modeology) Look up roman numeral notation for this next bit. A V-I is called

Building off of this to talk about functional harmony (I recommend a book called modeology) Look up roman numeral notation for this next bit. A V-I is called a perfect cadence in the major scale, and pretty much any other mode in which those chords naturally occur. The most important tones are the major 7th, which is one semitone away from the root and has a strong desire to resolve up, and the perfect 5th, which is a very stable sound that wants to fall up a fourth or down a fifth to the root. As such, the third can be major, minor, omitted, or replaced and the function of the chord remains pretty much unchanged. This is called modal interchange, since we are borrowing from a different mode for the root, in this case any mode other than Ionian (major). Mode changes the strong and weak cadences, however, so be mindful your alteration doesn't make a progression fall apart. My favorite is ii7, iio7, and Imaj7. Another topic thats fun is tritone substitution, but that would make this a borderline blog post. o in this context is a diminished chord, which also means that 7 is double flat (bb) because theory. It can get crazier, there's tons of YouTube videos that explain it better. But