Extended

Extended chords are 5 tone chords that are extended past the 7th

• ex. 9th, 11th, 13th

They are called compound because they are greater than one octave

Compound chords are played with the 7th.

• this is the principal difference between an add2 (aka add9) chord and a 9th chord

Recall that added dissonance results when a note is added to a chord that is a semitone away from an existing chord tone. For this reason, we will notice that major 9 chords are less dissonant than major 13 chords, since the 9 chord contains a 1-2-3-5-7, while the 13 chord contains 1-3-4-5-7 (the 4 is a semitone away from the 3, resulting in the dissonance in the later).

Variants:

• dominant (ie. standard) extended chords
  • major triad + dom7 + extension note
  • ex. C11
• major extended
  • minor triad + dom7 + extension note
  • ex. Cmin11
• minor extended
  • major triad + maj7 + extension note
  • ex. Cmaj11
• augmented extended
  • ex. C9♯11 (major triad, dom7, regular 9, sharp 11)
  • ex. Cmaj9♯11 (major triad, maj7, regular 9, sharp 11)

Eleventh (11th)

In dominant 11th chords (ie. standard 11th chords), typically the 9th is omitted

• this is not the case for maj11 chords or m11 chords, since the dissonant interval is not created
  • recall that maj11 means a major 7th is used, whereas m11 means minor 3rd is used

A perfect eleventh creates a highly dissonant minor ninth interval with the major third of major and dominant chords. To reduce this dissonance the third is often omitted

• a dominant eleventh chord can be heard 52 seconds into the song "Sun King", turning the chord into a suspended ninth chord (e.g. C9sus4, C–G–B♭–D–F), which can be also notated as Gm7/C.
• Another solution to tTypically, 11th chords omit the 9th and 13thhis dissonance is altering the third or eleventh factor of the chord to turn the problematic minor ninth interval within the chord into a major ninth.

Creating the chord on piano

To create an 11th chord (with 3rd omitted), simply:

• with left hand, play root octaves or 1-5
• with right hand, play major triad that is a whole tone down from the root

For example, C11 is formed by playing C in the bass and a Bb major triad on top

• Bb because Bb is a whole tone down from C

Thirteenth (13th)

Typically, 13th chords omit the 9th AND the 11th

Most commonly, 13th chords serve a dominant function (V13), whether they have the exact intervals of a dominant thirteenth or not.

• Typically, a dominant chord anticipating a major resolution will feature a natural 13, while a dominant chord anticipating a minor resolution will feature a flat 13

A thirteenth chord does not imply the quality of the ninth or eleventh scale degrees. In general, what gives a thirteenth chord its characteristic sound is the dissonance between the flat seventh and the thirteenth, an interval of a major seventh (ie. octave minus 1 semitone).

Creating the chord on piano

To create a 13th chord, simply:

• play the root and 3rd in the left hand
• add in the 7th and one semitone less than an octave of that 7th

For example, C13 is formed by play C and E in the left hand, and in the right, play Bb (the 7th) and A (the 13th)

• note: the Bb and the A are octave minus 1 semitone apart. This makes it easy to visualize the interval between the 7th and the 13th.