kitty Brazelton writing music NYU, History of Music Humanities, Columbia hit the books


  • major
  • minor
  • modulation
  • tonic
  • dominant
  • subdominant
  • DIATONIC SCALES:

    MAJOR & MINOR MODES; MODULATION


    DIATONIC SCALE IN MAJOR MODE & DEFINITION OF TONIC:

    There are 7 scale-steps in any diatonic scale. A diatonic scale is perceived as major when the scale-steps have the following template of intervallic relationships:

    major scale:  1   2   3   4   5   6   7    (1) etc.
    1 2 3 4 5 6 7 1
    tones between scale-steps: 1 1 1/2 1 1 1 1/2
    Because of the asymmetrical distances
    between steps in the scale,
    all steps are not equal.
    Each step has a different identity
    and harmonic role when heard in a melody.
    In the hierarchy, 1 is most important, then 5, etc.
      7 =the leading tone=1/2-step lower than 1
        5 =the dominant
        4 =the subdominant=5 steps below 1 (use octave displacement)
     3 =the mediant=fills the triad between 1 and 5
        1 =the tonic (note)
        I =the tonic (chord= 5-3-1 in any vertical combination)
        I =the tonic (key area=use of the above scale-steps only)
    [Please note: the second two "one's" are designated as Roman numeral I.]

    DIATONIC SCALE IN MINOR MODE:

    Every major diatonic scale, like the one diagrammed above, has a minor diatonic scale which shares its "key signature" or configuration of 1/2-steps and whole steps but starts two steps earlier, shifting the intervallic template to a new minor identity. This scale is called the relative minor. And the converse is true: if you start with a minor scale, a scale starting on 3 of the minor will be the relative major scale.

     

    minor scale:  6   7   1   2   3   4   5   
    becomes 1 1 1 2 3 4 5 5
    minor scale:  1   2   3   4   5   6   7  and the roles of the scale-steps shift to accommodate
    tones between scale-steps: 1 1/2 1 1 1/2 1 1
      Please note: if the tonic (key area) is minor,
    and 6=1, and the relative major starts on 3.

    MODULATION: TONIC TO DOMINANT

    The most common modulation of the major diatonic scale is to the dominant major diatonic scale. This means that the same order of intervallic relationships found in the original scale are shifted so that the order of half-steps and whole-steps begins at 5 instead of 1.

    This is more easily accomplished than it sounds. If you simply raise the scale-step 4 by a half-step (or #), the new relationships will be in place as you can see below:

     

    major scale modulated into the dominant key:  5   6   7   1   2   3   4#    (5) etc.
    1 1 1 1 2 3 4 5
    tones between scale-steps: 1 1 1/2 1 1 1 1/2
      4  must be raised a 1/2-step or sharped (#) to become a leading tone and maintain the order and relationship of 1/2-steps and whole-steps in a major diatonic scale = new 7
        2 =the dominant= new  5 
        1 =the subdominant= new  4 
     7 =the mediant=new  3 
        5 =the dominant (note) is now the tonic (note)= 1 
        V =the dominant (chord= 2-7-5 in any vertical combination)
        V =the dominant (key area=use of the above scale-steps only)
    [Please note: the second two are designated as Roman numeral V.]

    modulation from I to V (tonic to dominant key areas) occurs when 4 is sharped (#) and becomes a new leading tone. Then and only then, 4=7 and 5=1, etc.:

    NEW major scale:  1   2   3   4   5   6   7    (1) etc.

    MODULATION: TONIC TO SUBDOMINANT

    Almost as common is the modulation of the major diatonic scale is to the subdominant major diatonic scale. This means that the same order of intervallic relationships found in the original scale are shifted so that the order of half-steps and whole-steps begins at 4 instead of 1.

    One of the reasons this is the second most common modulation is because it can be accomplished so easily. If you simply lower the scale-step 7 by a half-step (or b), the new relationships will be in place as you can see below:

     

    major scale modulated into the subdominant key:  4   5   6   7b   1   2   3    (4) etc.
    1 1 1 1 2 3 4 5
    tones between scale-steps: 1 1 1/2 1 1 1 1/2
      3  becomes the new leading tone = new  7 
        1 =the dominant= new  5 
      7 must be lowered a 1/2-step or flatted (b) to become a new subdominant and maintain the order and relationship of 1/2-steps and whole-steps=the subdominant= new  4 
     6 =the mediant=new  3 
        4 =the dominant (note) is now the tonic (note)= 1 
        IV =the dominant (chord= 2-7-5 in any vertical combination)
        IV =the dominant (key area=use of the above scale-steps only)
    [Please note: the second two are designated as Roman numeral IV.]

    modulation from I to IV (tonic to subdominant key areas) occurs when 7 is flatted (b) and becomes a new subdominant. Then and only then, 7=4 and 4=1, etc.:

    NEW major scale:  1   2   3   4   5   6   7    (1) etc.

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