We've already looked at the major scale and the
minor scale. Now it's time to look at a different kind of scale, known as a mode.
Writing a tune in modes is both an ancient and a modern idea.
It was the most common form of scale
before the 17th century, and has been popular with composers once again, since around the end of the 19th century.
So what is a mode?
Let's look back to our C major scale.
Using just these same 7 notes - C D E F G A and B, it is possible to
create 7 new modal scales. It all depends where you start.
for example, let's start on the D instead of C:
We're still using only those same seven notes, but we're starting and ending
on the second note or supertonic of C major. That's a mode called the Dorian Mode.
And as you can see below, there's a mode starting on each of the other notes too:
Starting on the E (the third, or mediant of C major) we get the phrygian mode
Starting on the F (the fourth, or subdominant of C major) we get the lydian mode
Starting on the G (the fifth, or dominant of C major) we get the mixolydian mode
Starting on the A (the sixth, or submediant dominant of C major) we get the aeolian mode
Starting on the B (the seventh, or leading tone of C major) we get the locrian mode
That's six modes so far. The seventh is the one starting on the C itself. That's known as the ionian mode. But
as it's a mode that contains exactly the same notes as C major itself, it's an unusual way to describe a scale these days.
Let's say you are given a piece that uses just the white notes of the piano
- C D E F G A and B. How can you tell whether it is in C major, A minor, or if it's in a mode?
Let's look at the following melody as an example:
Several clues give away D as an important note in this melody, not least that it begins and ends with a D. Of these the
ending note is far more important - melodies do often (but by no means always) end on the key note. The other prominent note in
the piece is A which is the dominant (or 5th) of D - an important note to any kind of D scale.
There are no F sharps or C sharps, so that rules out D major as an option.
So that leaves either D minor, or D Dorian mode. However, D minor also has a sharp 7th note (leading note) - a C sharp. We've
already established that there are no C sharps, so that must mean it is in D Dorian.
Modes starting on other notes
The examples we've used here have all used the seven notes of the C major scale.
Don't forget the same modes can be built on all the other scales.
For example, if we take the notes of the scale D major:
D E F# G A B C# D
We could use a Dorian mode starting on E which would make: