There are three different minor scales: the natural
minor, the harmonic minor, and the melodic minor. All three
are used, and they differ by only a few notes. All minor
scales have the third degree lowered (as least as compared with
the corresponding major scale), but differ in their treatment
of the sixth and seventh notes.
The natural minor is identical to the Aeolian mode.
Thus, if you play a C major scale, but start on A, you've played
the A natural minor scale:
A B C D E F G A
\ / \ / \ / \ / \ / \ / \ /
w h w w h w w
(w = whole step, h = half step)
Note that this means that the natural minor modes will all match
major modes: To get the associated Major key you just shift
the starting point up a third in pitch.
To find the natural minor key, start with the major scale and
lower the third, sixth, and seventh notes. An easy way to figure
out the key signatures is to simply add three flats (or take away
three sharps, or some combination) to the major key signature.
Thus, if you start with C (no sharps or flats), C minor has three
flats. The key of A major (three sharps) becomes A minor (no
sharps), and D major (two sharps) becomes D minor (one flat). If
you have less than three sharps, cancel out the sharps with an
equal number of flats, and add any flats that are left over. Note
that three flats is also the key signature for E♭ major, and E♭
is the minor third of the C minor scale (and triad). Thus,
counting up a minor third from the root will give you the key
signature for the minor key of that root.
Perhaps the easiest way to visualize this is to think of the
Circle of Fifths. If you can find your key on the CoF, you simply
count three keys in the "flat" direction to find the key signature
for the corresponding minor key. It works the other way, too. If
you have a known key signature (for example, five flats, D♭), you
can count *back* three keys (i.e., go 3 in the sharp direction)
around the CoF and find the root for the relative minor (B♭ minor).
Because C minor and E♭ major have the same key signature,
C minor is known as the "relative minor" of E♭ major. Similarly,
F♯ minor is the relative minor of A major, A minor is the relative
minor of C major, G minor is the relative minor of B♭ major, and so
on. Try it! What is the relative minor for D major? What is the
minor key that has one sharp in the key signature? (Answers at the
end of the lesson.)
You can play the natural scale as shown below. I've put
fingerings for both melody and bass together, but you may find it
difficult to play both hands in the same area of the fingerboard. I
suggest taking the right hand up an octave (12 frets up, or up 7
frets and over a string). As always on the Stick(R), you can transfer
the pattern anywhere on the neck, to play a minor scale in any key.
The only problem with the natural minor scale is that it
omits the "leading tone." In common practice (Baroque and Classical
music), the leading tone is one of the most important notes of the
scale. It even has its own abbreviation: LT. The LT is always a
half step below the root (or octave) of the scale, and almost always
resolves to the root. In fact, it is the LT (as the major third of
the dominant V chord) that is responsible for the "dominant" sound
of the V chord. If the seventh tone is lowered (as it is in the
natural minor), you end up with a minor dominant V chord - almost
a contradiction in terms. It just doesn't provide the same feeling
of resolution (cadence) that a major V chord does. Try playing:
Am Dm Am Em Am |////|////|////|////|////|and then contrast it with
Am Dm Am E Am |////|////|////|////|////|
playing E major this time. (The Am-Dm-Am is just to get your ear set in the key of A minor.) Makes a difference, doesn't it? As long as the root (I) chord is minor, the whole key will tend to sound minor, whether the V is minor or not. However, making the V minor destroys some of the resolution feeling of the cadence, so common practice composers weren't entirely satisfied with it. So, they developed...
The harmonic minor scale has the same key signature as the
natural minor, but has the seventh note restored to its original
(major) position. Thus, the A harmonic minor scale is:
A B C D E F G♯ A
\ / \ / \ / \ / \ / \ / \ /
w h w w h w+ h
(w+ = augmented second)
This made many composers happy: it restored the LT, which
was important to their melodies, and it restored the major V (not to
mention the dom V7), which was important to their harmonies and
cadences. (Perhaps I should mention that an authentic cadence is
V-I in common practice, not to be confused with the IV-I "plagal
cadence" [think "Amen"] or the V-VI "deceptive cadence." OK, maybe
I *shouldn't* mention it.)
I should point out here that you can play the harmonic minor
scale starting on different notes to get the equivalent of modes,
just as in the major scale modes. Does anyone use them? Sure.
They're good for some of the altered jazz chords. Do they have
their own names (like Dorian)? I have no idea.
Notice the stretch from 6 to 7? The interval is an
augmented second. It is not considered a minor third, even
though both have 3 half steps, and are "enharmonically" the same.
If you play an augmented second and a minor third in isolation,
they'll sound identical (at least, they will on modern instruments,
or anything tuned in equal temperment). The common practice
composers considered augmented intervals too dissonant to use (it
does sound a little funny, doesn't it?), so they had *another*
problem. The harmonic minor provides all the right scale tones
for constructing the triads, but bollixed up the melodies with that
odd augmented interval. So, composers decided to keep the harmonic
minor for figuring out chord progressions, but for melodies they
would use...
Since composers were unwilling to lose their LT, and didn't
like the augmented leap from 6 to 7, there was only one thing to do:
raise the sixth back to where it is in the major scale. The key
signature stays the same: its just that now the sixth and seventh
notes have naturals (or sharps) where they have flats or naturals in
the natural minor. The third is *always* lowered. (If you raise the
third again, you end up with a major I triad, so you're completely
back to the major key.)
A B C D E F♯ G♯ A
\ / \ / \ / \ / \ / \ / \ /
w h w w w w h
This makes the sixth a major sixth. Unfortunately, this makes
the scale lose quite a bit of its minor character. Try playing it:
However, since you don't *really* need that leading tone when
you're going *down* the scale, there's no real reason to raise the
seventh when descending. And if you don't have to raise the
seventh, you don't have an augmented second between the sixth and
seventh, and don't have to raise the sixth either. But if you lower
the sixth and the seventh, you're right back to the natural minor.
The melodic minor scale has two different forms (at least in
classical music): one for going up, and a different one for going down.
The ascending melodic minor is the one immediately above, with the
raised sixth and seventh. The descending form is the same as the
natural minor at the top. Jazz sometimes (usually?) uses the ascending
form for both directions. Of course, it can be hard to tell, as one
often throws a few extra notes in the scale anyway. ;-)
And, of course, you can start the melodic minor scale on any
note, and play the corresponding modes.
Do all these different minor scales have different chords
associated with them? Yes. But that's for next time.
The relative minor of D major is B minor.
E minor has one sharp (corresponding to G major).
-- Grant D. Green