The response from Andrew Wasson , of Creative Guitar Studio, on: "How do I find the key center of a Chord Progression when it is just Power Chords?" Sent from ~ Mario
This video will explain how when using Power Chords it is important to pay close attention to the root notes of each powerchord. The roots will correspond to the major or minor scale of the home chord for the progression. Since powerchords are only an interval, they do not have a chord quality. So, to judge the key center one must view the movement of one powerchord to the next as a series of intervals, then match those intervals to a particular key center.