This little blog is about the chord sequences derived from the Major Scale.
These blogs will help: Major Scale Formulaand Major Scale Chord Formula.
If you are not familiar with those concepts just follow along and see what makes sense.
Three Major chords, three minor chords and a diminished chord at the end.
The diminished chord is represented by either "˚" or "dim".
The convention is to reference these chords numerically using Roman Numerals.
Get used to both conventions.
Using the C Major Scale, if I was to play C, F, G then I would be playing a I, IV, V formula.
Why not just say C, F, G then?
An example highlighting the benefit of numerically naming the chords comes when changing key.
What chords would I play if I was to change key to G?
Using the formula I would simply play the 1st, 4th, and then 5th chord of the scale.
If your singer was Celine Dion and she decided to leave the band (much to everyone's joy), you would get a new singer in. Say it turns out to be Randy Blythe from Lamb of God?
Different types of singers I hope you would agree.
The change in voice could/should/would warrant a key change to match the singers range.
First, convert the song's chords in to Roman Numerals, then deduce the chords by applying the Roman Numerals to scale you want to use.
In the key of G a I-IV-V sequence would be G, C, D.
So it turns out we like the sound of certain chord formulas.
Generally speaking we find certain chord formulas pleasing.
In the 1950's they couldn't get enough of I, vi, IV, V. It was very popular back then.
In the 1980's there were a lot of I, V, vi, IV songs but really, there are still a lot of I, V, vi, IV songs.
Jazz guys and gals would be left walking around like zombies if we took ii, V, I sequences away from them.
There is a great sketch by Axis of Awesome called 4 Four Chord Songwhich highlights the I, V, vi, IV chord sequence, medleying all the songs the could manage in to a few minutes - there is a serious amount of cheese factor in there - you've been warned.
Play around, create cool formulas, see where you can play them, what key sounds best, which key is easiest for that formula?