What is a Neapolitan 6th?

Question

In studying music theory I have heard the term Neapolitan 6th quite a few times, but I'm not quite sure what it is. What is a Neapolitan 6th and how is it used in a composition?

Answer 1

In the key of C major the second degree of the scale (D) gets lowered a half step to D-flat. Then just build a major triad... D flat, F , A flat. ... The Neapolitan 6th chord is an expressive alternative to the ii6 chord, and most often found in the minor key, although there are plenty of examples of it in major. Its genesis is very simple. Take the progression iiº6 - V7 - i in a minor key, and use the lowered second degree of the scale for the supertonic triad.

Answer 2

In technical terms, it's a bII in first inversion. Also known as a bII6, the 6th designating that it's in 1st inversion. The n6 is used to get to the dominant of a chord and then to tonic. N6 - V (or V7) - I. For example, in C major, it would be a Db major triad with F (the 3rd of the chord) in the bass. So this Db major triad built on its 3rd, F, will resolve to a G major triad (or a G major dominant 7th) which is the dominant (V or V7) in C major. The F in the bass would reslove up to a G, the Db would resolve down to a B natural (this looks awkard but it's the most common resolution of this chord), and the Ab would resolve to a G as well. Add a D in there and you now you've resloved a Db major triad into a G major triad. From here, you can resolve the dominant G major chord to the Tonic C major chord. The N6 always resolves to a V (or V7), never directly to a I. This chord is very useful for bringing the harmony back from far-off keys to the original tonic. It became commonplace during the time of mozart and haydn.

Answer 3

A Neapolitan Sixth chord (N6) is an alternative, non-diatonic chord that can be used in a similar way to a secondary dominant (V/V - V - I). It is classified as a major chord built on a lowered second scale degree in first inversion (hence the 6). You generally find it in minor keys where the ii chord would be diminished if built from the diatonic scale. This would change the chord progression from ii° - V(7) - i to N6 - V(7) - i. There is no "right" or "wrong" use of it, it all depends on what color you are looking to create in a composition.

I hope that made sense and answered the question you were looking to get answered. If you still have questions about it, feel free to reach out!

Garrett

Answer 4

A Neapolitan 6th chord belongs to the pre-dominant family, and is therefore used to approach the dominant chord in a key. More specifically a Neapolitan 6th chord is a major chord built on the lowered 2nd scale degree, and placed in first inversion.

For example, in the key of C major the 2nd scale degree is D, so a Neapolitan 6th would be a D-flat major chord (as D-flat would be the 2nd scale degree lowered by a half-step) in first inversion, so spelled from the bass up: F-A-Db (though, to be perfectly clear as long as the F is in the bass it doesn't really matter what order the other two pitches are in, as long as they are there. F-Db-A would be just as good).

Voice-leading would then usually have the flatted 2nd scale degree go to the leading tone (NOT tonic yet), while the F would move to the dominant. The dominant harmony would then be resolved as usual with the leading tone moving up to tonic and the 5th scale degree leaping down to tonic in contrary motion. Other resolutions do exist, however, depending if a cadential 6/4 is used.