I'm still always behind... but you have also not completed your exercises so I don't feel too guilty
. And I hope when I do get around to writing lessons, that they are informative and quality.
THE NEAPOLITAN CHORD
As Brandon had pointed out on the fugue thread a long time ago, the NEAPOLitan chord refers to Naples, because it was very popular among a group of composers based there including Alessandro Scarlatti, I think.
Please open up the attachment "Neapolitan - Voice Leading."
Once again I will begin with a short discussion of the Neapolitan chord's melodic properties. Whether in an inner voice, merely adding color, or an outer voice, central to the melody, you should be aware of the sound of the lowered 2nd degree note.
Just to review (I think you already know the theory involved), the Neapolitan chord is a major chord on the flattened second degree of the minor scale. In major the Neapolitan chord is a sort of mode mixture and would have two altered notes. During the Baroque period, however, N was confined to minor and was far from common. More on its history later.
Example one in e-minor shows how the 2b (flattened second degree) might be approached in an actual melody. The 2b wants to move downwards towards the leading tone (and thus dominant harmony). In this example, however, it first passes through the tonic note (whether as a passing tone or in an I64).
Notice that two consecutive minor seconds result, between the 2b and the tonic and between the tonic and the leading tone. Their sound is very distinctive and you should get to know it well so that you can purposely choose the effect in your music. And in your music, all chromaticism should be purposeful. Rather than just deciding to throw in a few chromatic chords here or there, as composers we must carefully attempt the affects we want using all the resources we have. Given the melodic nature of the Baroque period, it is wiser to write a nice melody, perhaps incorporating that 2b, perhaps not, and only afterwards look back to see if a N chord sounds appropriate to the melody's character. Less wise would be to contrive some awkward melody with the sole purpose of using this or that chromatic harmony.
Example two shows the 2b leaping directly to the leading tone. This diminished 3rd is an interesting effect.
Example three harmonizes the melody of example one. Notice the the fourth degree is usually in the bass, that is, N is usually in first inversion, N6. N6 often passes through I64 before reaching V. N has a harmonic character startlingly different from its melodic character. The harmony can be quite noble. Example four harmonizes the melody of example two.
If you consider the normal circle of fifths in minor:
I - iv - VII - III - VI -(dim)- ii* - V - i,
you see that one of the "fifths" is actually a diminshed fifth; there is a diminished fifth between the roots of VI and ii*. This often goes unnoticed in sequences, and explains why VI ii6 is more common than VI ii (the bass would leap by a diminished fifth). The N chord simply corrects this fifth and moves it to between N and I:
I - iv - VII - III - VI - N -(dim)- V - i.
Since in minor V is more common than v, we get two major chords a tritone apart - a significant departure from the tonal system and thus very colorful. Examples five and six illustrate circles of fifths, first with ii* and then with N, so you can compare.
Example seven illustrates how easily parallel fifths result when moving from N to I64. The good voice leading almost requires that the sixth degree and the 2b both move downwards. Most composers place the 2b above the sixth degree so that you get parallel fourths instead. Some authors say these parallel fifths are acceptable. Either way, the listener won't be able to tell or even care!