Alright, starts out simple enough. It's a cute little riff in E Major. I understand how the modes work, and I get that the first riff works out, because even as the apparent 'root' changes, all of the notes are still relative to one another in the same diatonic scale. But then at 0:14, he literally plays the exact same riff, only in G major instead of E major. I am scratching my head was to why this form of modulation works. G is not found anywhere in the E major scale. G major and E major are not relative scales at all, and in fact, G major and E minor are. Is there some kind of rule that states what number of semi-tones a pattern can shift, in order to sound mildly disjointed but still appropriate for a song? I know there are supposed to be a few tricks for modulating from whatever key/mode to whatever other key/mode you want, but I don't really know what they are, and I suspect they are much trickier than this.
It's in the tricks. Rhythmic and melodic tricks to change scales using a two-note overlap in the scales, and using the rhythm to emphasize the change which was already in progress.
I'll use this tab for reference: http://tabs.ultimate-guitar.com/p/paul_ ... up_tab.htm
The transition from the first part to the second is a descending run in E major grouped into three groups of three notes on the first line. Nine notes there, plus the first note of the next line, which needs to be considered. Look at how these ten notes fit the scales:
-The first nine are E major, while the last one is firmly in the new key. The timing separates them too, so the first note that isn't in E major is the start of a new line.
-The last three are G major. He plays through the seven notes of E major, then once the octave repeats, there are two notes that overlap between EM and GM, while the last one the first that doesn't fit EM, there is a three note run at the end that fits GM
-The last note falls on the first beat of the next measure/line, which reinforces the key change. It is the third note in the key of GM. That's a three-note pattern, and the last measure ended with three patterns of three notes each. Two notes overlapped, and the final one fell on the first note of the next measure/line, a rhythmic trick to emphasize a key change that has already been in progress for a few shared notes.
Two tricks used here that make this key change work:
-Find notes that overlap between the two keys you're changing between and use those to make the transition. Set up the transition before you change key, so you're already into the shared notes with the new key.
-Use timing and percussion to support the change. If the first note of a new key comes on the first beat of a measure, it feels right, better than doing it a few notes into the measure.
-Extra note: When the rhythm pattern is the same in both parts, the transition feels less abrupt. Changing one of melody/rhythm at a time can help make both smoother transitions and interesting variations on parts.