Relative Key Substitution

I’m in the midst of completing this section in the Harmony masterclass and am hoping for a tiny bit more context on the below excerpt.

“The verse section of Beat It by Michael Jackson utilises power-chords, but if we add the diatonic thirds to each chord that would give us the chords E♭m, D♭, and C♭. This progression outlines the common “Aeolian Progression” that we learned about in E♭ minor.”

  1. How is “adding diatonic thirds” applied in the above? (such as are we lowering a certain note by a minor third or a major third or something else to achieve this) – I assume I’m missing something fundamental here

  2. When you refer to outlining progressions is this loosely speaking? Such as in the “Aeolian progression” is i – bVII – bVI- bVII then you could do bVI – bVII – i – bVII and it still applies to this category?

Hey @sdavisjr ,

#1 – Let me clarify your question. Am I correct in rephrasing to: how do we add diatonic thirds to these chords? Similarly, how do we know if they’re major or minor thirds? If that’s correct, then the answer requires you to understand essential diatonic harmony, which should have been covered in the first two groups of lessons in Harmony Basics (Diatonic Harmony & RNA)? In the instance of Beat It, I have established that the key is E♭m. Thus, i = minor, ♭VII = major, ♭VI = major. You can see this by stacking diatonic thirds (from E♭m scale) from the respective scale degrees (R, ♭7, ♭6). For example, a 3rd above ♭7 degree is the 2nd degree, plus another 3rd is the 4th degree. ♭7 + 2 + 4 = ♭VII (major triad), because the distance between ♭7 and 2 is a major 3rd (indicating major tonality).

#2 – You are correct. As you progress through the class you will discover this moreover. You may have already seen in the Axis Progressionthat the progression doesn’t always cycle from the I chord. Some progressions are fairly firm, and others can be manipulated but still considered a variation of their progression name.

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