So I've been learning about the scales (major, minor etc) and how all the scale degrees are related to the major scale.
So in a minor scale, if you saw m3 it would mean a flattened 3rd degree in relation to the major scale defined semitones.
For example...
That all seems fine, but I noticed that there's a degree notation using roman numerals and even with the major scale it suggests that some of the degrees are actually minor?
See https://en.wikipedia.org/wiki/Roman_numeral_analysis#Major
So in this ^^ example (in the key of A), instead of playing all major chords, I would play a mixture of major and minor chords:
- A major
- B minor
- C# minor
- D major
- E major
- F# minor
- G# diminished
Why is this?
Update
I left the following comment on the top response so far:
so to recap: a chord is typically built from thirds of the scale. The quality of the chord associated with a melodic degree is determined by these thirds. So I counted the semitones between the thirds and found the quality (minor/major) matched the harmonic degrees indicated by the roman numerals. But what I don't understand is why the 7th is 'diminished' and not minor? As the semitones between the 7th degree and the degree a 3rd way from it (which would be a 2nd/9th) is 3 semitones; suggesting a minor third.
By looking back at the full list of interval qualities (e.g. P1, m2, M2...all the way up to...P8) I can see that 6 semitones would be an augmented/diminished quality A4/d5
, but I can't see how that distance in semitones get's applied by counting semitone distances based on 3rds
Ps, what's the correct terminology to use above where I've labelled it 'QUALITY' and 'ROMAN QUALITY'?