Major Scale

The Major Scale, represent by the intervals 1 2 3 4 5 6 7, is the basis of western music.  It is the one scale where everything in the theory of western music starts.

Musical notation has standard key signatures only for major keys (also for their relative minor keys, but there are no standard key signatures written for harmonic or melodic minor scales.  It is safe to assume that any given western song is either in a major key or one of the other six modes of the major scale.

If a musician masters the major scale and all of its modes, that musician will be able to perform music with ease.  Here are the twelve keys in 12-EDO standard tuning:

Learning the circle of fifths and the standard keys will get anyone very far,  The circle of fifths is how you can add sharps, one sharp at a time, by counting up five intervals at a time.  For example, in the key of C, five intervals is 1=C, 2=D, 3=E, 4=F, 5=G.  So G is the fifth.  The sharp to add is the fourth.  So, add one sharp for the key of G.  That one sharp is F#.  To go from there, count five intervals from G: 1=G, 2=A, 3=B, 4=C, 5=D.  So there are two sharp in the key of D, and those are F# (the old sharp) and C# (the fourth) from G.  Keep adding a new sharp on every fourth for the key of every fifth.

Flats can be added, too, by working backwards.  Count backwards five to get the key with one more flat.  This time, the second interval counting back is the note that is flat.  So from C: 1=C, 2=B, 3=A, 4=G, 5=F.  So in the key of F, B is flat.

Each mode has it's own distinct character.  The most common modes are the Ionian (Major) and Aeolian (Minor).

The Ionian major scale has a happy, proud, or even triumphant tone.  It should be the first thing that comes to mind to use when you want to convey such emotions.

The Aeolian minor or "natural minor" scale is a sad sounding scale.  It sounds sadder than other minor scales, to me, and also to most musicians, from what I understand.  If you wish to convey a tone of melancholy or deep sadness, this is the scale for you.

Dorian mode offers a breezier, jazzy tone.  It is often used in jazz and blues, but can also be found in much renaissance period music, particularly that of Germany and England.

The Phrygian mode offers a more fiery tone that sounds more reminiscent of Iberian music.  It can also be used to convey an angrier tone than the Aeolian and Dorian modes.

Lydian mode is like Ionian mode, but has a little weirdness.  If you are familiar with the theme songs from cartoons such as "The Jetsons," or "The Simpsons," then you are familiar with the way the Lydian mode sounds.

Mixolydian is a very popular mode, which is very common in folk, bluegrass, blues, and funk music.  The similarity to Ionian mode offers a happier tone, but the dominant seventh offers a little "snap," which gives a little energy to the melody.

Locrian mode is the most difficult to wield.  There are stories that this mode was forbidden by the church, as the imperfect fifth made many people think of evil.  To this day, the mode sounds evil to many people's ears.  It is the only mode that does not have a perfect fifth.  This mode can be used to convey anger or a feeling of impending doom.

C: No sharps nor flats: Notes C D E F G A B

Modes: (All tonalities with key signature all natural)

    C Ionian (Major)

    D Dorian (English)

    E Phrygian (Spanish)

    F Lydian (Cartoonish)

    G Mixolydian (Dominant)

    A Aeolian (Natural Minor)

    B Locrian (Evil)

Notice the two bottom keys, F# and Gb, are enharmonic equivalents in 12-EDO standard western tuning, but they are not necessarily the same in other tuning systems.  It is possible to continue with keys like C# and Cb, but in 12-EDO, these are enharmonically equivalent to Db and B, which were already described.  I've heard many musicians, typically piano players, argue that there is no such thing as the key of C#, because Db is enharmonically equivalent and simpler; however, just as there are some contexts where it makes more sense to say one note rather than its enharmonic equivalnet, there could be instances where a key change could start from or end up in C#.  For example, if a song has a key change that takes the key up a major third (which is a fairly common key change), and started in the key of A, it would transition to the key of C#.  I would not say that it transitions to the key of Db, because Db is the diminished fourth of A.

In fact, this is really where 19-EDO can get modern musicians into trouble.  In any particular musical key, tonality works essentially the same way and the music sounds very similar, but when a key change occurs, nuances like described above begin to matter significantly, as a key change to C# and a key change to Db sound quite different in 19-EDO.

Tonalities for the major scale are:

I The tonic is major.  Use the major third, perfect fifth, You can also safely add the major seventh, major ninth, major sixth etc.

ii The supertonic is minor.  Use the minor third and perfect fifth.  You can also add some color with the minor seventh.

iii The mediant is minor.

IV The subdominant is major.

V7 The dominant is dominant.  This means that you use the major third and perfect fifth with the dominant seventh.  In standard tuning, the dominant seventh is the same as the minor seventh.

vi The submediant is minor.

vii°/2 The subtonic is half diminished.  This means that you use the minor third with the diminished fifth and possibly the minor seventh.  (A full diminished tonality is different by having a diminished seventh a half step lower than the minor seventh)

Also, it should be noted that every major key has a relative minor key.  If you hear someone say "relative minor," try to think of the Aeolian mode off of the Ionian major.