Page:Harmony - its theory and practice.djvu/19

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Chap, I.]
Its Theory and Practice.
17

satisfactory effect, i.e., which does not necessarily require to be followed by some other combination. For example, if the student will strike on the piano any of the following pairs of notes, pausing between each,


\relative c' {
  \omit Staff.TimeSignature
  <c g'>1 |
  <c c'> |
  <c e> |
  <e g> |
  <c a'> |
  <e c'> | \bar "|."
}

he will find that each is more or less satisfactory. A consonant chord is a chord of which all the notes make consonant intervals with one another.


\new PianoStaff {
  <<
    \new Staff {
      \omit Staff.TimeSignature
      \clef "treble"
      \relative c' {
        <e g c>1 | \bar "||"
        <c f a> | \bar "||"
        <a' fis'> | \bar "||"
        <g d'> | \bar "||"
        <d g bes> | \bar "||"
        <gis e'> | \bar "||"
        <e a cis> | \bar "||"
        <f aes des> | \bar "|."
      }
    }
    \new Staff {
      \omit Staff.TimeSignature
      \clef "bass"
      \relative c {
        c1 | \bar "||"
        f | \bar "||"
        <d d'> | \bar "||"
        <g b> | \bar "||"
        g | \bar "||"
        <e b'> | \bar "||"
        a | \bar "||"
        des, | \bar "|."
      }
    }
  >>
}

Let the student play each of these chords separately on the piano—they are not intended to be connected—and he will find that each by itself produces a satisfactory effect. When he has learned, later in this chapter, which are the consonant intervals, he will see that no others have been used in these chords.

17. A dissonant interval, or Dissonance, is a combination of two notes which by itself produces an impression of incompleteness, so that the mind urgently feels the need of something else to follow. Let the student strike on the piano the following pairs of notes, pausing, as before, after each.


\relative c' {
  \omit Staff.TimeSignature
  <f b>1^"1" | \bar "||"
  <g f'>^"2" | \bar "||"
  <b f'>^"3" | \bar "||"
  <b c,>^"4" | \bar "||"
  <b c>^"5" | \bar "||"
  <c d>^"6" | \bar "||"
  <e, f'>^"7" | \bar "||"
}

Everyone will feel the incomplete effect of these combinations, and that they require to be followed by something else to be satisfactory. Let us try. We will put after each of these dissonances a consonance, and it will be at once felt that the completeness which was before wanting has now been obtained.


\new Staff {
  \clef "treble"
  \omit Staff.TimeSignature
  \time 4/2
  \relative c' {
    <f b>1^"1" <e c'>  \bar "||"
    <g f'>^"2" <c, e'> | \bar "||"
    <b' f'>^"3" <c e> | \bar "||"
    <b c,>^"4" <f a> | \bar "||"
    <b c>^"5" <a c> | \bar "||"
    <c d>^"6" <b d> | \bar "||"
    <e, f'>^"7" <e e'> | \bar "||"
  }
}

The consonance which follows the dissonance is called the Resolution of the dissonance. The laws according to which dissonances are resolved will be learned later.

18. A dissonant chord, or Discord, [1] is a chord which contains at least one dissonance among the intervals made between the various notes. Like a dissonant interval, a dissonant chord

  1. The term "Discord" is also sometimes applied merely to the dissonant note itself.