Tonality

I order to play a major scale one has to use the major formula. If say I want to play a D Ionian instead of the "original" mode Dorian, all I have to do is change the notes of that scale in order to produce the same intervals between notes, keeping in mind that the first note is not to be changed, otherwise you'll be changing the name of said scale.

A D scale is "originally" D E F G A B C D, or 1 2 b3 4 5 6 b7 8, also 1+1/2+1+1+1+1/2+1.

The Ionian major scale as a formula like so 1+1+1/2+1+1+1+1/2 or 1 2 3 4 5 6 7 8.

So all I have to do is think of 1 2 b3 4 5 6 b7 8 and see were the half tones are.

So...between the second and third degrees and between the sixth and the seventh degrees.

This means will have to raise by half step the third and the seventh, cause if we compare the two formulas side by side, that's were the difference will be - 1 2 3 4 5 6 7 8

1 2 b3 4 5 6 b7 8

So D Ionian will be D E F# G A B C# D, we have raised the third and the seventh.

The same process will have to be performed to change any scale to another, or the inverse process of bringing notes down depending and what's the objective, going form major to minor or minor to major.

If I want to change say, a G mixolydian for example, to a G lydian, again I must compare the two formulas side by side - 1 2 3 4 5 6 b7 8

1 2 3 #4 5 6 7 8

This time the fourth has to be raised by a half step and also the seven. We had originally 1+1+1/2+1+1+1/2+1 and became 1+1+1+1/2+1+1+1/2, the scale itself will look like this:

G A B C# D E F# G - G lydian scale

If you have a song that's played in G major you'll probably see the key signature at the beginning of the piece with a F sharp for the whole song, for all the tonalities you can use, either major or minor you have two possible frames one can use, one for flats and one for sharps. For the flats you'll have B E A D G C F, and for the sharps F C G D A E B. You don't put them all, just the one's needed for the tonality in question.

For the flats if I want for example a song in A flat I'll put all the flats from B to A plus one more, so we'll have B E A D, you can think that the tonality of the song is the flat before the last one. And so the scale for Ab Ionian will be Ab Bb C Db Eb F G Ab, and at the beginning of the piece one will have B E A D flats on the lines of the staff.

The sharps just think of the tonality you want the last of the sharps should be the 7th, so half a tone below the root of the scale. For example, if I want a E Ionian scale tonality just think that the 7th of that scale has to be half a tone below that E, so D#. Now you know you'll have to spell the key signature for sharps until you reach the D#, so F C G D. And the scale will be E F# G# A B C# D# E and you'll get F C G D sharps at the beginning of the piece. When looking for the tonality of a song with sharps in the key signature the last sharp is the 7th of that tonality.