Lesson 23- Modes

A mode is a type of scale. You've already learned to write major and minor scales in previous lessons. Music based on major and minor scales came into common usage in the early 1600s, and of course we have been using them ever since. Before the 1600s, composers wrote in what were called modes. There was a resurgence of interest in modes toward the end of the 19th century, with composers like Debussy. Modal melodies can be very beautiful, and their study is certainly worthwhile! Such study of modes can get quite in-depth, and is a fascinating field. However, for our purposes here as a rudimentary music theory course, we shall only delve into their basic construction so that we can identify and write them.

The first and perhaps most important thing to remember about modes is: A mode is distinguished by the pattern of tones and semitones, not by the actual pitches used.

Take a look at this C-major scale, starting on a middle C and proceeding upward for one octave:

  

The tones and semitones have been indicated, and you can tell by that tone-semitone pattern that this is indeed a C-major scale.

What if you were to take this same C-major scale, but instead of starting on a 'C', started on a 'D' and proceeded upward for one octave. It would look like this:

  

It still has the pattern of tones and semitones that belong to C-major; it's just that the scale now starts and ends on a 'D' instead of a 'C'. We call this scale the dorian mode. We say that the note 'D' is the key note, or final, of the mode. A scale that runs from what appears to be the second degree (supertonic) up to the second degree an octave higher is said to be in the dorian mode.

We can start a scale on all the different notes of our C-major scale above. For example, if we write a scale from the mediant to the mediant, we get the phrygian mode:

  

(The tone-semitone pattern is still that of the C-major scale.)

Subdominant to subdominant gives us the lydian mode:

  

Dominant to dominant produces the mixolydian mode:

  

Submediant to submediant produces the aeolian mode:

  

And leading tone to leading tone makes the locrian mode:

  

Incidentally, when you write a major scale from the tonic note up to the tonic note, you are also forming a mode, called the ionian mode! So something in C-major could technically be said to be in C-ionian, though we more often than not simply call it 'C-major'.

What mode is this? We see a key signature of A-major (three sharps) where the scale runs from the mediant note to the mediant note one octave higher. That means it is the phrygian mode. Simple!

You remember in Lesson 16 that we determined keys by identifying the key signature. Now we need to expand that idea a little. Though key signature helps to determine key, we need to examine the melody closely and see its construction and direction. The following excerpt, on first glance, looks like it could be G-major, because there is a key signature of one sharp, and there are no leading tones (D#) to make E-minor (the relative minor) a possibility:

  

But, in fact, this is in the aeolian mode. Here is the procedure to arrive at that determination:

1- One sharp in the key signature makes it either:

• G-major
• E-minor
• One of the seven modes

2- It can't be E-minor, because that would require the presence of D# to create the leading tone that's necessary to emphasize E as a tonic.

3- It could be G-major, but look at the melodic shape: there is much that points to 'E' as a significant note, rather than 'G'. The opening interval of 'E' to 'B' (perfect 5th) solidifies 'E' as an important note. The first three notes of bar 3 are members of a triad built on E. The shape of the melody at the end "pulls the ear" toward 'E', and indeed 'E' is the final note. So even though we know it cannot be E-minor, there is much evidence that 'E' is some sort of "tonic". It is in such cases that we need to examine the possibility of the use of a mode. 'E' is the sixth note of the G-major scale, and the mode based on the sixth note is the aeolian mode. Therefore, this excerpt is in E-aeolian.

Explanations:
The first excerpt is in E-flat Lydian. This is because the key signature is that of B-flat major, but the note 'E-flat' seems to be very important:

• It starts and ends on E-flat.
• Each beat (except for the first beat of the last bar) starts with a note from an E-flat triad.
• E-flat is the 4th note of the B-flat scale; therefore, this is in the Lydian mode, which is the mode based on the 4th note of a major scale.

Each of the other examples are in their respective modes for similar reasons.

As stated before, this lesson is simply a rudimentary introduction to modes. The question of whether an excerpt is major, minor or modal can be very interesting and complicated, but in this lesson we are focusing on modes in their "purest" state.

Review Lesson 12c for another way to construct modes.