music theory general knowledge exchange

 

In some ways of thinking, the actual key of a song becomes irrelevant.  Either because you may want to play it slightly higher or lower, or if you simply want to analyze the relationships between chords.  So, writing a chord progression in roman numberals makes it easier to discuss relationships.

 

An uppercase is major, a lowercase is minor.  If you're in the key of C playing a I - IV - V progression, the chords will be C, F, G.  If it's i - iv - VI - V, then it's Cm - Fm - A - G.  The numbers are based on degrees of the major scale, so even if you're in the key of Cm (which the minor 3rd is an Eb), a i-III-v progression would be Cm E G, not Cm Eb G.  If you wanted to represent Eb, you would represent it as bIII.  When me and a friend are writing riffs, we usually discuss it this way, i.e. "Should we go to the minor third before or after going to the flat 5th?"

 

Using the notes in a major key, the natural major/minor relationships are as follows: I IV and V are major, ii iii and vi are minor and vii is minor-diminished (1, b3, b5).

 

Louie Louie and TONS of other 50's and 60's rock and R&B songs, and standard 12-bar blues utilize some version of the I IV V progression.