Defining modes

Modes... A very controversial topic that seems to confuse the hell out of many people... Opinions vary from "Modes are completely useless - the major and minor scales are all you need" all the way to "The next best thing since sliced bread!" In fact, many people fail to make the distinction between a number of fundamentally different concepts such as "modes", “scales”, "modal music versus tonal music" and others. I'll try my best to be as concise and accurate as possible, and yet remain simple! In this topic, we will simply define modes (even that is often controversial!), leaving their practical usage for later topics. Theory We define a mode as follows: a musical mode is an ordered series of interval with respect to a starting note (whose absolute pitch is not specified). In other words, a mode simply defines a series of relative pitches; for example: 1 2 b3 4 5 6 b7 8 What this example mode definition says, is the following: given the (unspecified) starting note (1),the second note is a major second away from it (2), the third note is a minor third away from it (b3), the fourth note is a perfect fourth away from it (4), etc. An equivalent way of defining a mode consists in enumerating the sequence of intervals between the various relative pitches (as opposed to their definition with respect to a starting note); for the example mode above that would be: W H W W W H W The example above happens to be a seven note mode, and it just so happens that Western music deals primarily with those, but of course you can define an infinite number of modes using an arbitrary number of constituent notes. Many traditional Indian and Chinese modes use 5 notes, for example. A mode is different from a scale! The mode is completely abstract, since it does not impose a starting pitch. If you specify the starting note by its absolute pitch, and apply the definition of the mode, you obtain a scale. The scale can be thought of as the melody of the mode once you indicate the starting note. For example, starting with the note C, the mode above becomes: C D Eb F G A Bb (C)If you start with A, you get: A B C D E F# G (A) The mode is the same, but the scales are clearly different. Modes have been dominant in Western music until the late Middle-Ages. Pope Gregorius is known for his complete and sophisticated theorisation of the musical systems to be used by the church, and still known today as Gregorian Chant or Plain Chant. In that system, the definition of the various modes consisted as much in the specification of the relative pitches (as we did) as in the rigorous definition of the melodic organization and prescribed cadences (that we don’t need to worry about for now). The Gregorian modal system is heavily based on the Pythagorean system, and the names of the various modes come from the ancient Greek names (although Gregorius had them all mixed up!). We still use these names today (see below), but our names are again different from what they used to be in the Middle-Ages.