Modes are very cool. They can seem a little confusing, but are more intuitive than they might first appear. Most importantly they give lots of traditional music its unique sound, so they're worth getting to grips with. I've broken this section down into three parts to make it a little easier to assimilate. Feel free to skip Part 1 and head straight to Part 2 for a quick-fire explanation.
Part 1 - Scales recap
Let's begin by establishing what we mean when we refer to playing 'in' a particular mode. Take a tune such as Cluck Old Hen, and compare it to Cherokee Shuffle. They both belong to the Key of A, and yet you can hear that Cluck Old Hen has a slightly different sound, that could simply be described as 'modal'. In order to understand a little better what this means, let's recap on scales briefly.
Take any major scale. Each note in the scale is separated by either one fret (half steps), or two frets (whole steps):
WHOLE - WHOLE - HALF - WHOLE - WHOLE - WHOLE - HALF
So a C major scale can be represented like this:
As outlined in the scale lesson we can change the 'character' of scale by making changes to this pattern of whole and half steps. Our natural minor scale flattens the third, sixth and seventh note of a scale, which means the pattern of whole steps and half steps also changes to look like this:
WHOLE - HALF (flattened) - WHOLE - WHOLE - HALF (flattened) - WHOLE (flattened) - WHOLE
So our C Natural Minor scale looks like this:
We can change the key signature to indicate the three flats so that we don't have to do so on the stave:
Without having to think about it these two scales already mean we're playing in two different modes. The Major Scale of any key is referred to as the IONIAN mode, and the Natural Minor of any key is the AEOLIAN mode. As they are so common we would more often than just refer to them as being Major or Minor though, without reference to their modal names. The important point to note is that playing in different modes just means changing the pattern of whole and half steps between notes in a scale, which then changes the feel of the key you're playing in.
Part 2 - Putting it into practise
Explanations of modes often begin with the following outline of their various names and forms. We can take solace in the fact that our standard major and minor patterns are nestled amongst a bunch of others that all have different and similarly strange names:
Ionian (major): Whole - Whole - Half - Whole - Whole - Whole - Half
Dorian: Whole - Half - Whole - Whole - Whole - Half - Whole
Phrygian: Half - Whole - Whole - Whole - Half - Whole - Whole
Lydian: Whole - Whole - Whole - Half - Whole - Whole - Half
Mixolydian: Whole - Whole - Half - Whole - Whole - Half - Whole
Aeolian (minor): Whole - Half - Whole - Whole - Half - Whole - Whole
Locrian: Half - Whole - Whole - Half - Whole - Whole - Whole
For the moment let's ignore most of this, but simply note again that playing in different modes means playing different patterns of steps between notes. A history of modes and their Greek origins can be found elsewhere, but here we're primarily interested in how to make use of them in our playing.
Along with our major (Ionian) and minor (Aeolian) patterns there are two more modes that it's useful to become familiar with; these are Mixolydian and Dorian. The reason these are important is that they feature more often in popular and traditional music, and have a much more familiar sound than some of the other modes. Let's quickly look at each.
The Mixolydian Mode:
For an example of a Mixolydian tune, take a listen to Red Haired Boy, Goodybye Girls I'm Going To Boston or June Apple. These are all in A Mixolydian, which means they use an A scale, but due to their modal nature have a slight alteration that makes them a little less 'major' sounding. Let's stick with A for the moment and take a look at our standard major scale:
If we change this scale so it is in the Mixolydian mode, all we do is flatten the seventh step so it's a G natural rather than a G sharp. Here's the scale again with the note changed:
Now because we're playing 'within' this mode we don't want to have to think about the seventh step being flattened all the time. So instead we change the key signature to represent that these notes are always G naturals. This is the cool bit. Notice how our key signature is now the same as the key of D (take a look at my scales lesson for more info on key signatures):
This is essentially the simplest way of thinking about modes. Take a key, and when you play up the scale from the starting root note of that key, use the scale pattern from a different key. So the key of A Mixolydian starts on an A but uses all of the notes of a D scale. So if you were to play the same scale but start on a D note you would be playing...well...in D.
The Dorian Mode:
Dorian tunes have a slightly darker feel than those in Mixolydian or Ionian modes; Cluck Old Hen and Elzic's Farewell are good examples. Exactly the same principle applies to the Dorian mode, except in this instance the scale pattern we're using flattens both the third and seventh scale steps. So our A scale looks like this:
Now let's do the same as before and change the key signature to account for this. You might have already noticed that the A Dorian scale is the same as the G scale (starting on the A though). So let's change our key signature to reflect this:
Part 3 - Conclusion
So that's modes in a nutshell, as it relates to Western folk/traditional/fiddle music at least. You can find a handy mode calculator at music-theory-practice.com if you want to delve a little deeper. A little cheat sheet for the various scales used by different modes could look something like this:
Key of G:
G Mixolydian: start on G, use a C scale.
G Dorian: start on G, use an F scale.
Key of D:
D Mixolydian: start on D, use a G scale.
D Dorian: start on D, use a C scale.
Key of A:
A Mixolydian: start on A, use a D scale.
A Dorian: start on A, use a G scale.
Key of E:
E Mixolydian: start on E, use an A scale.
E Dorian: start on E, use a D scale.
Key of F:
F Mixolydian: start on F, use an B scale.
F Dorian: start on F, use an E scale.
Key of C:
C Mixolydian: start on C, use a F scale.
C Dorian: start on C, use a B scale.
If you'd like more info on modes, with some more tune examples and technical exercises, then drop me a message to arrange a lesson.