#1
Hello,
I have a question:
I use the major scale to find out if a chord fits my key. Lets say I want to know if D fits in the key of C major. So I build the major scale for both root notes. Now if the third, the fifth and the root of D are in the key of C, it's all good. In this case they don't, so I have to lower the third by half a step and it becomes Dmin. That process is clear to me.
My question is: if I want to do the same thing in a minor key, do I have to use the natural minor scale like I used the major scale in the example above?
Thanks
#2
Yes...except when building a chord on the fifth scale degree you use the natural minor scale with a major seventh.

So if you are using the Cm scale then you would have these notes:

C D Eb F G Ab Bb C
So the chord built off that G would be G Bb D (Gm) however when the chord built on the fifth scale degree (the dominant) moves to the tonic chord (in this case Cm) the resolution is stronger and more satisfying if the dominant chord is major. Thus you would use G major to resolve back to Cm.

Thus for all the chords you would use C D Eb F G Ab Bb C (the C natural minor scale) except the fifth scale degree which you would use the C harmonic minor = C D Eb F G Ab B C.

Melodies built over that dominant to tonic movement ( G major to C minor ) would use the melodic minor scale because a scale run from G to Ab to B to C is pretty ugly with a semitone then three semitones then a semitone. We need the fifth scale degree, we need the tonic, and we need the major seventh scale degree so to resolve the ugly melodic run we raise the minor sixth to a major sixth to smooth things out. C D Eb F G A B C = Melodic minor.

Apart from when harmonizing a dominant to tonic root movement (chord built off the fifth scale degree moving to a chord built of the tonic) then you would harmonize the notes of the minor scale with the natural minor scale.

To do this you can just start on each note of the scale and counting that note count up in thirds. (Basically you start on a note and skip a note then use the next note then skip a note and use the next note.

So C natural minor is
C D Eb F G Ab Bb C

If you wanted to know what kind of D chord would be diatonic to Cm you would start on D and skip Eb and use F then skip G and use Ab. You would have D F Ab - this is a diminished triad. Ddim.
If you wanted to know what kind of Eb you would use you would start on Eb and skip F use G skip Ab use Bb. This gives you Eb G Bb = Eb major.

You do this for all of them except the fifth as explained above you would make it a major chord by raising that Bb to a B.

Of course you don't ONLY have to use chords or notes from the scale. But it's definitely useful to know what chords go with what scales.
Si
#4
You have several options when working with minor keys. Three of the most popular minor scales are...



        There are many more, but these three will give you plenty to work with for now.

        The tones of the natural minor / aeolian mode are (using C as the tonic):
        C D Eb F G Ab Bb C
        These are the same tones comprising the Eb major scale, with which C minor shares the key signature of three flats.

        The tones of the harmonic minor are:
        C D Eb F G Ab B C

        The melodic minor has an ascending form and a descending form.
        Ascending: C D Eb F G A B C
        Descending: C Bb Ab G F Eb D C (this is the same as the natural minor)

        Have fun!
        All things are difficult before they are easy.
        - Dr. Thomas Fuller (British physician, 1654-1734)
        Quote by Freepower
        For everything you need to know - gpb0216.
        #6
        Quote by Jayerrr
        Why would I choose one minor scale over another?

        That would be a question for you to answer for yourself after getting the sounds of these scales in your ears, but a quick answer might be "for the sake of variety".
        All things are difficult before they are easy.
        - Dr. Thomas Fuller (British physician, 1654-1734)
        Quote by Freepower
        For everything you need to know - gpb0216.
        #7
        The original reason is as I described above.
        But then it became a trend (particularly in the metal genre) to harmonize the harmonic minor and melodic minor scales as independent scales on their own.

        The thing is, in a given key you aren't restricted to a particular scale.

        If you are in a minor key for instance, you can borrow chords from the parallel major key - it is done all the time.

        For example if you're in Cm and you play F major instead of the diatonic F minor then it would usually be considered borrowed from the parallel major (C Major). But it could have been arrived at by harmonizing the melodic minor scale (C D Eb F G A B C). Either way it's a Major IV chord in a minor context.

        For this reason I personally didn't see any point learning to harmonize the harmonic and melodic minor scales. (once I'd learned to harmonize the natural minor and major scales then I didn't have to learn how to harmonize other scales. I just used whatever chord I wanted and knew what notes were adjusted to get that chord and so what would work melodically).

        However, the answer to your question is this:

        If you're in the key of Cm then your diatonic chords will be those built off the natural minor scale with the exception of the Major V chord (G major).

        If you're in the key of Cm then harmonizing the Melodic and harmonic minor scales will result in some chords that are not diatonic to the key of Cm. Those chords can still be used effectively in the key of Cm.

        If you're looking for chords diatonic to the key of Cm then you wouldn't be harmonizing those scales.

        Having said that, the use of non diatonic chords can provide some interesting and desirable sounds.
        Si
        #8
        Quote by 20Tigers
        If you're in the key of Cm then your diatonic chords will be those built off the natural minor scale with the exception of the Major V chord (G major).

        Converting the V to a major chord is, in fact, the primary function of the harmonic minor scale.
        All things are difficult before they are easy.
        - Dr. Thomas Fuller (British physician, 1654-1734)
        Quote by Freepower
        For everything you need to know - gpb0216.