Could someone elaborate on chord progressions and roman numerals?

Question

I've learned everything I know on guitar from sitting around trying to play it by ear so now I have to go back and learn the fundamentals.

I often see people talk about chord progressions and use I, IV and so on. Could someone summarize what is meant by this?

I understand theres probably alot behind it I just to have a vague idea.

Answer 1

Ok, very simply: chords are built using the notes of a particular scale.  Lets say we use the key of C as an example.  Then the major scale (do re mi fa sol la ti do) in the key of C is:  C D E F G A B C

If we start on the first note of the scale (C), skip a note (D), use the next note (E), skip a note (F) and use the next note (G) we get the following chord:  C E G.   This is known as a C major chord and is represented by the roman numeral I (Its the "1" chord because the root or starting note of the chord is the first note of the scale and its capitalized because its major.)

If we start on the second note of the scale (D), skip a note (E) use the next note (F) skip the next note (G) and use the next note (A) we get the following chord: D F A, which is a D minor chord and is represented by the roman numeral ii Its the 2 chord because its root is the second note of the scale and we use lower case because its a minor chord.

And so on.  The chord built on the third note of the scale (E) will be E G B or E minor, which is represented by the roman numeral iii.

The chord built on the fourth note of the scale (F) is F A C, which is an F major chord, represented by the roman numeral IV.

The chord built on the fifth note of the scale (G) is G B D, which is a G major chord, represented by the roman numeral V.

The chord built on the sixth note of the scale (A) is A C E, which is an A minor chord, represented by the roman numeral vi.

The chord built on the seventh note of the scale (B) is B D F, which is a B diminished, represented by the roman numeral vii (with a little circle next to it).

The basic rule to remember is that the 1, 4 and 5 chords in any given key are always major (I, IV and V), while the 2, 3 and 6 chords in any given key are always minor (ii, iii, and vi), and the 7 chord is always diminished.

So, in the key of G, the scale is: G A B C D E F# G, and the chords are:

I = G major

ii = A minor

iii = B minor

IV = C major

V = D major

vi = E minor

vii = F# diminished.

In the key of F, for example, the scale is: F G A Bb C D E F

and the chords are:

I= F major

ii= G minor

iii = A minor

IV = Bb major

V = C major

vi = D minor

vii = E diminished

Knowing the basic rule, you should be able to figure out what the chords are for any given key if you know the notes of the major scale.

Answer 2

Ok without getting complicated and into the actual notes of a scale.

There are 8 notes that are called Do Re Mi Fa So La Ti and Do in every scale.

for every chord, you skip one note. So, starting with the "I" chord it would be Do Mi So

II - Re Fa La

III - Mi So Ti and so on

there's also the fact that some of these scales are major and some are minor.

Since you learned guitar by ear, it shouldn't be too hard to just listen and pick these out, but for reference it's

I - Major

II - Minor

III - Minor

IV - Major

V - Major

VI - Minor

VII - Diminished

VIII - Major (same chord as I)

Answer 3

Actually there isn't a lot behind it.  The roman numarals stand for the chord number in the scale, (i.e. I=1, II=2, so on and so forth).

So, say you were playing a C major scale. I would be your 1 chord or C major (C,E,G), IV would be the 4th chord F major (F,A,C).

So, you could have a progression reading; I-VI-III-VII-III-V, and in C major that would be; CM, Am, Em, Bm, Em, GM.  To pretty much boil it down, the roman numeral is the root of the chord in the scale.