Changes

'''Modes''' are basically repurposed uses of existing scales by altering which note is used as the tonic. The most common mode is the Aeolian, which uses the 6th note of the major scale as its root. As we've already studied, this ''is'' the natural minor scale.

Historically in music, the term mode ('''modus''' in Latin) was used to refer to various common practices in music, such as common rhythms, etc. See [http://en.wikipedia.org/wiki/Mode_(music) wikipedia] for more information. We are only focused on the repurposed scales. Historically, there have been 3 separate times and locations where this has occurred. One is the Greeks, and one is the medieval churches in the West. We are not concerned with these, as their basic foundation of music theory and scales tend to differ from the ones we have learned. That leaves us with the "Modern" conception/usage of modes.

Ionian and Aeolian are the major and minor scales, respectively. We should be quite familiar with their sound and impact on us musically by now. 4 of the other 5 modes differ from either Ionian or Aeolian by only one note and can be considered '''synthetic scales''' that retain most of the core impact of those scales but provide a slightly different color. They are often termed as "moody". These can easily substitute for the major or minor scale for the given key, provided that the current harmony does not cause their use to become too dissonant. The other mode, Locrian, shares most notes with the minor scale. It additionally has a m2 like Phrygian, but the biggest difference from all the other modes is that it has a diminished 5th. This can give it a very unsettling feel and can be substituted for minor , when a Phrygian isn't enough.

'''Pitch Axis ''' is a method of composition that tends to retain a common root note across a chord progression, simply changing the quality and embellishments of the chord. A sample sequence could be A, Am, A{{dim}}, A+. No single scale contains all these chords. Instead, one could use the A Ionian, Lydian, or Mixolydian over A. Then A Dorian, Phrygian, or Aeolian over Am. Then A Lydian or Locrian over A{{dim}}. And finally A Harmonic Major, Augmented, or Whole Tone over A+ (those are technically not modes based on the major scale, but still scales with a tonic note of A).