Originally Posted by: snojones

Chris,

I am confused.... Isn't D minor the iv if A minor?

I'll (try) to answer the question you asked Chris; you're correct that it is part of A minor. Because of that, it's a modulation or a shift of it being within A major to A minor.

In create a song or a melody, you want to evoke a mood. If you were to playing only major chords, you'd never have the melancholy vibe Chris has mentioned. So as you structure stuff, your shifts may not follow strict major/minor path but you modulate the melody in order to create that tension you need to create that mood. I'm guessing you're not thinking that it is an either major or minor deal but when you look at the rules, music creation isn't going to always play Team Major or Team Minor so you hve to account for those thngs in modulation shifts etc.