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Wednesday, December 31, 2014

Pentatonic Scales

                The prefix “penta” means five, so a pentatonic scale is a scale composed of five pitches.  These scales are used heavily in Eastern music, folk music and many forms of improvisation.  Technically, any five pitches can be combined to form a pentatonic scale.  Eastern music contains many types of pentatonic scales.
                The music of Western Europe developed separately from that of other nations throughout history.  The music theory and structure that we study in my courses (and in most North American and West European schools) comes from this Western European history.  Western tonal music is based off of 7 pitches within a given diatonic key.  Our key system can be based on either a major or minor tonality. 
                The Middle East, Eastern Europe, Asia, Africa, Australia and even Native Americans all have their own musical history and structure that differs in many ways from Western Music.  Some of these areas (particularly the Middle East and Asia) developed a formal music theory which we classify as Eastern music.  This difference creates a split in music theory when referring to either Eastern or Western music. 
                There are two main types of pentatonic scales: hemitonic and anhemitonic.  Hemitonic scales contain one or more semitones.  Anhemitonic scales contain no semitones.  Anhemitonic scales are the type of pentatonic scales that occur in Western music, since they relate best to our diatonic keys.  They will be the focus of the rest of our discussion.
                 The two main types of anhemitonic pentatonic scales that we identify in Western music are major and minor pentatonic.  The major pentatonic scale is composed of the 1st, 2nd, 3rd, 5th and 6th scale degrees of a major diatonic scale.  This scale is useful for the implementation of simple improvisation techniques because it does not contain the 7th scale degree.  This makes it a good scale for use improvising over both major 7th and dominant 7th chords.  In addition, the scale does not contain the 4th scale degree which is considered an "avoid" tone in jazz improvisation. 

                The minor pentatonic scale is composed of the 1st, 3rd, 4th, 5th and 7th scale degrees of the natural minor diatonic scale.  This scale is useful for the implementation of simple improvisation techniques because it contains all the pitches of the minor 7th chord along with one additional passing tone.  Also, the five pitches of a given minor pentatonic scale are the same five pitches of the relative major pentatonic scale from a different starting point.  Essentially, the one scale can be used when improvising over both a major 7th chord and its relative minor 7th chord.


                Since there are five pitches in a pentatonic scale, the anhemitonic pentatonic scales can actually be arranged in 5 different orders (from 5 different starting points).  In Western music, we label one of these as the major pentatonic and another as the minor pentatonic.  The other three are seen as inversions of the major or minor pentatonic scales.  We use this perspective to best relate the pentatonic scales to our major and minor diatonic scales.

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