During much of the Common Practice Period (1600-1900), nonharmonic tones (PT, NT, app, sus) appear as momentary 9^ths, 11^ths, and 13^ths. Since the duration of these nonharmonic tones is only a fraction of the chord’s duration, they are considered embellishments rather than actual members of the harmony.

During the nineteenth century, composers increased the length and emphasis of these nonharmonic tones. So instead of a seventh chord, the listener hears a 9^th, 11^th, or 13^th chord for almost the full duration of the harmony. By the end of the nineteenth century, these extensions were fully accepted as members of the chords.

The 9^ths, 11^ths, and 13^ths often occur in the soprano, creating new melodic possibilities. The chords most commonly occur in root position, since the inversion of a five or six note chord may obscure the function of the original chord. In functional harmony, the 9^ths, 11^ths, and 13^ths shadow the seventh of the chord and resolve down by step.

The most frequent usage includes adding a 9^th or 13^th to a dominant seventh (V⁷)chord, the 9^th or 11^th to the subdominant seventh (ii⁷) chord, and the M9 or a M6 and M9 (6/9) added to the tonic (I) chord. (The 6/9 chord is a triad with an added M6 and M9, and does not include a 7^th.) Observe the Arabic number guides next to the tall chords below, indicating the intervallic structure.

Voice Leading

1. Ninth Chords

The 9^th as a suspension that becomes a functional part of the dominant ninth chord.

The 9^th as an appoggiatura that becomes a functional part of the dominant ninth chord.

The flat 9^th as a chromatic neighbor tone that becomes a functional part of the dominant flat ninth chord.

The le passing tone from example 1g becomes the flat 9^th of the dominant seventh chord in example 1h. Additionally, the tonic triad is enhanced by the added M6.

2. Thirteenth Chords

The 13^th as a suspension and an appoggiatura, either of which becomes a functional part of the dominant thirteenth chord.

In example 2d, the tonic is enhanced by the added M6, the ii⁷ chord has an added M9, and the V⁹ chord has an added M13. Note that in the dominant thirteenth chord the 13^th replaces the 5^th of the chord. In example 2e, the colorful use of the appoggiatura flat 13^th (me) becomes part of the G7 chord resolving to a tonic triad.

3. Eleventh Chords

The 11^th as part of a 4-3 suspension that becomes a functional part of the dominant eleventh chord.

The suspension resolving into a dominant ninth chord and then becoming a functional part of the dominant eleventh chord.

A ii⁷ chord with a double appoggiatura becoming integrated into the ii¹¹ chord.

Examples from the Literature

The examples below show the various stages of integration of 9^ths, 11^ths, and 13^ths into traditional triads and seventh chords.

Dominant Chords

In the Chopin example, the repetition of the nonharmonic B’s (as NT and PT) make the B a functional part of the V⁹ chord.

The length and accent of the high A appoggiatura in the Mendelssohn example produces a V⁹ chord over a C pedal.

The Schumann example has a m9 added to the G7 chord.

Strauss elaborates the dominant seventh with chromatic passing tones leading to an arpeggiated V⁹ chord.

Here Strauss uses the 9^th and 9^th as passing tones:

*9 spelled enharmonically

The Chopin example below introduces the secondary dominant ninth chord and includes an accented neighbor tone 11.

In the Saint-Saens ii – V – I cadence, the 9^th of the Dm9 chord is suspended to become the 13^th of the G13 chord.

Inversions of the dominant ninth chord with typical accompaniment patterns (such as do – so, – re – so,) are found in the waltz and march. In the Strauss example below, note the similarity between the G^o7/B (m.2) and E⁹/B (m.6) chords. The final tonic chord has an added sixth.

Subdominant Chords

The Mendelssohn example shows the subdominant ii⁹ implied by the long G appoggiatura and dominant V⁹ chord by the repeated C notes.

In the Grieg example, the Em9 resolves to the dominant A11. The melodic motive in measure 3 includes both the 9th and 11th of the dominant chord.

A beautiful use of a subdominant ii¹¹ chord:

Tonic Chords

The examples below show the Impressionist technique of adding a 6^th and/or 9^th to the tonic chord. (See chapter on 20^th Century Compositional Techniques.)

The continuous use of the M6 with the G major triad creates a I^add6.

The continuous use of the M6 and M9 with the E major triad creates a I^add6/9.

The dominant 9^th leading to the tonic triad with the added M6, then to a tonic M9, and then back to the added M6. In the Amaj9 chord, both the 7^th and 9^th resolve down by step.