Triads Tertian

Introduction to Triads and Seventh Chords

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  Tertian: built of 3rds chords
  
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  Triad: fundamental tertian,
  
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    Three-note chord
    
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    Consisting of a 5^th divided into two superimposed 3rds
    
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    4 possible ways
    
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      Augmented: +5(M3+M3),
      
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      Major: P5(M3+m3),
      
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      Minor: P5(m3+M3)
      
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      Diminished: °5(m3+m3)
      
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    Root, third, fifth
    

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  Four-note chord
  
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  Extend a tertian triad by adding another 3^rd on top of the 5^th of the triad
  
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  Interval between the root and the added note is some kind of 7^th (major, minor, diminished)
  
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    Major seventh (M7) : major triad + major 7^th
    
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    Major-minor seventh (Mn7) : major triad + minor 7^th
    
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    Minor seventh (mm7) : minor triad + minor 7^th
    
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    Half-diminished 7^th (ᶲ7): diminished triad + minor 7^th
    
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    Diminished seventh (°7): diminished triad + diminished 7th
    

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  Root position
  
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  Any part of a chord might appear as the lowest tone
  
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  Root position, first inversion ( or just 6), second inversion ( )
  

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  Root position
  
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  Root position (7), first inversion ( ) , second inversion ( ), third inversion ( )
  

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  Analyzing music using numbers derived from the Baroque (1600-1750) system called figured bass or thoroughbass
  
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  Keyboard player in an ensemble read from a part consisting only of a bass line and some symbols indicating the chord to be played above each bass note
  
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  The symbols consisted basically of numbers representing intervals above the bass
  
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  Notes could actually be played in any octave above the bass
  
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  Baroque keyboardist reading the figured bass followed the key signature
  
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  Root position triad might be major, minor or diminished
  
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  Accidental next to an arabic numeral in the figured bass could be used to raise or lower a note (e.g. 7b, #)
  
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  Horizontal line mean to keep the same note of chord (e.g. means to use the same bass note for a root position triad followed by one in first inversion)
  
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  Bass-position symbols (e.g. I or V )
  

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  Sometimes called pop symbols
  
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  Developed for use in jazz and 20^th and 21^st centuries popular music
  
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  Facilitated the notation process and served to provide sufficient information to allow the performer to improvise within certain bounds
  
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  Lead-sheet symbols appear along with a melody
  
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  Indicate the chords that are to be constructed below
  
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  C6 means a C triad with an added M6 above the root
  
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  Slash chord notation: C/G mean C major triad over a Gin the bass (second inversion)
  
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  Frequently differ from one edition to the next
  
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  F#m7(b 5)/C means F# minor seventh chord over a C in the bass line with a lower fifth of the chord (C#-C♮)