Modes - The Theory (lesson)

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In the previous modes lesson we described what modes are, and a practical way of diving into them. However, modes are a complex subject, and the theoretical underpinnings are fascinating. Once you thoroughly understand the previous lesson, spending some time here can really help you with concepts all across music. So now we know what modes are, lets see what they mean in theory terms and how they were generated in the first place.

How Do We Generate Modes?

We're going to start out by listing all of the modes of the Major scale, along with their formulae - look closely, there may be questions ...


I have also included a column called "scale degree" - this will become clear soon.

The first thing I hope you spotted was that the Ionian mode has an identical formula to the Major scale. (See, I told you you were already using modes!). Yes, that's right, the Ionian mode is another name for the Major scale.

Next, although we haven't had a lesson on minor scales yet, you may have spotted that the Aeolian mode has the same formula as the Natural minor scale ... yes, that's right, you already know the Aeolian mode because it is identical to the Natural minor scale! So we've learnt 2 modes already without trying.

Interesting though that is, the real lesson here is that there is a pattern in each of the successive modes (I have listed them in this order deliberately). With a little more examination you will see that for each successive mode's formula, we take off the first letter, move the rest of the letters along and put the first letter on the end.

This gives us a practical way to generate the modes of a scale, based on a techniques of moving through the notes of a scale. The rule is this:

Pick a major scale. To generate each mode, you move through the notes of the scale, up to the degree listed above for that mode, then play through the scale, starting on that note, but playing notes from the original scale. What this does is two things. First, it shifts the root note from the Major scale root note, to the note that is the degree of the scale to which we have moved. Secondly, since we are starting some of the way through the scale it also shifts the spacing of tones and semi-tones (T & S) into a different relationship, as reflected by the formulae for each mode that I gave you above.

That's a bit of a mouthful, so lets look at an example - the modes of the C Major scale. Notes in C major are C,D,E,F,G,A,B,C - here is one of the CAGED shapes for C Major:


Our first mode is the Ionian, which is the Major scale itself, lets ignore that for now, no explanations should be necessary. Instead, lets look at the Dorian mode. The Dorian mode is mode 2, so we generate the unique formula for Dorian by moving up a degree to D, and playing the notes out of the C Major scale, which would be D,E,F,G,A,B,C,D - it would look like this:


Since we started on D, we would call this "D Dorian", and you'll notice that although we are using the scale of C Major to select our notes, we have ended up with a scale with a root note of D, which you should take into account when writing songs around this mode.

If you want to turn this around and for instance find the notes in a specific key such as "C Dorian" you need to work backwards. What scale has the note C as its second degree? The answer is Bb, here:


So to figure out a C Dorian scale you would look at the notes in the key of Bb, which are Bb,C,D,Eb,F,G,A,Bb. Applying our rule and starting on the second degree ( C ) we get our C Dorian scale as C,D,Eb,F,G,A,Bb,C


When doing it this way around, you must also take account of the fact that different modes have different characteristic chords that fit with them. So for instance, Dorian mode has a Minor 7th feel to it - if you move from C Major to C Dorian, you are also moving from Major to Minor. Modes are characterised ad Major or Minor based on the interval between the 1st and 3rd notes. Not surprisingly, if the interval is a minor 3rd, the mode is characterised as minor, if its a major 3rd, it is characterised as major.

So you see we can work it both ways, going from a scale to a mode, or from a mode to a scale, and of course with practice you won't need to figure the notes out at all, you will just think "Dorian" and your fingers will play it - but that's a LOT of practice by the way!

You can use the same principle above to figure out the notes for any of the modes listed. Its also important to point out that for every mode, we are using the notes out of a major scale, just with a displaced root note, so learning modes is simply a case of re-using the major scale shapes you already know, and altering where you place the root note of that scale in the pattern. This means that you from the CAGED system you have 5 options for playing each of the modes.

Again, What exactly is a Mode?

So when all is said and done, is a Mode a specific pattern of notes, or just a scale played up a few notes?

People disagree on this - my answer to that question is that they are both. The essence of what a mode is, is the Tone/Semi-tone formula you use to construct it - Dorian is Dorian no matter what key it is played in, its the relationship of the notes that counts. But the selection and structuring of modes is done by an orderly progression through the scale you are generating the modes from. You'll notice that we have picked only 7 of the possible combinations of tones and semi-tones - others are possible, but that moves us into the realms of new scales. Modes of scales are strictly generated in the way I have described using movement through the degrees of the scale to generate the formulae for each.

Is That All There is to Modes?

Well we have really just scratched the surface of modes here, but by the time we have covered all of the modes listed above in more detail you will have learnt pretty much everything that most people mean when they talk about modes.

To be accurate, what we have discussed here are the Major Modes, meaning the modes generated from a Major scale. It is actually possible to generate modes from any scale at all though. So for instance, there are modes of the Pentatonic scale, Harmonic Minor scale, Melodic Minor scale and so on. Notice I didn't mention the Natural Minor scale here - although we use it a lot and call it a scale, a more accurate way of looking at the natural minor scale is as a mode of the Major scale (the Aeolian).

If you want to look at other modes (and there are some pretty obscure ones!) I suggest you buy a reference book such as The Guitar Grimoire: A compendium of Formulas for Guitar Scales and Modes. The techniques for mode construction remain the same no matter what scale you use, but sometimes its easier to look them up than to figure them out yourself.

That's it for this lesson. In the following lessons we are going to take a tour through the modes, look at example scales and discus chord voicings.

If you have any questions you know where I am!

Once again, thanks to Tank for proofreading!