[felixdcat]

This might be a stupid question, but I haven't found an answer.

When is a key of a song minor? Because, I know the major keys and the formula:

I, ii, iii, IV, V, vi, vi


If a key is minor, so it means it comes from a minor scale? Is there a way to "reach" it from the major scale, because I read you only need to know that the major scale.

Thanks!

[allthumbs]

I can tell you how it works in chords in a key. In the Key of C, the minors are the ii,iii and vi or D,E and A. Since the vi is the relative minor of the root,C, that makes the key A minor. I always found it interesting that minor keys don't have a Key signature in standard. In the above example the key sig would be for the mother key C even though the tune is being played in minor.

[Fretsource]

A song's in a minor key when it uses notes of the minor scale, rather than the major scale.

There are two ways to get the minor from the major.

1. - to get the tonic minor from the major (That's the minor that starts on the same note as the major. e.g., A major and A minor)
Flat the 3rd, 6th and 7th notes of the major, (especially the 3rd. but not always the 6th and 7th)
A maj = A B C# D E F# G#
A min = A B C D E F G

2. - to get the relative minor from the major (that's the minor that begins on the 6th note of the major scale, e.g., C major (CDEFGAB) and A minor (ABCDEFG). Both use the same notes but starting in different places - so they have the same set chords but A minor starts the set from A:
Am Bdim C maj D min E min F maj G maj

Minors are more complicated than majors because there are also 2 other slightly different forms of the minor scale that produce a couple of extra chords.

[AX7221]

Upper case roman numerals means a major traid, lower case means a minor triad, a superscrip o (like a degree symbol) means diminished triad, and + means augmented triad.

So, natural minor (the one thats the same as major but different starting point is): i, iio, III, iv, v, VI, VII, i

The way I remember the pattern is for major the 4 and 5 are major like the root, then for minor the 4 and 5 are minor like the root. Then if i keep in mind the 2 for minor and 7 for major are diminished then the rest are minor (for major chord prog) and the rest are major (for minor chord prog).

the other two, harmonic minor is: i, iio, III+, iv, V, VI, viio, i
the melodic minor is: i, ii, III+, IV, V, vio, viio, i

("o"s are suppose to be superscript)

On thing I'm unsure of (maybe somone else can fill me in), is the augmented roman numberals are uppercase, and the diminished ones are lower case, is that because augmented triads have 2 major 3rds and major chords start with a major third, then diminished are lower case because they're 3 minor thirds and minor chords start with a minor third?

[Fretsource]

Originally Posted by AX7221

On thing I'm unsure of (maybe somone else can fill me in), is the augmented roman numberals are uppercase, and the diminished ones are lower case, is that because augmented triads have 2 major 3rds and major chords start with a major third, then diminished are lower case because they're 3 minor thirds and minor chords start with a minor third?

Yes - that's right.

A couple of corrections, though, if you don't mind...
Diminished triads, such as ii° or vii° have only two minor thirds, not three.

Also, you should call the minor scale or key that starts on the 6th degree of the major scale, the relative minor, rather than the natural minor as natural minors can start anywhere, not only on the 6th degree.