4

Usually, a dominant will have two voices approaching the tonic's root. Most traditionally, the leading melody comes from a semitone below, while the other (generally the bass) simply jumps between the roots:

X:1
L:1/4
M:
K:Am
%%score (T1 T2) (B1 B2)
V:T1           clef=treble
V:T2           clef=treble
V:B1  middle=d clef=bass
V:B2  middle=d clef=bass
%            End of header, start of tune body:
% 1
[V:T1] "V⁷"">↑"^g,    "i"a,
[V:T2]       e,    e,
[V:B1]       d,    c,
[V:B2]    ">↑"e,,    a,,

The other voice may also approach the root from less far away than a fourth and from above, like

X:1
L:1/4
M:
K:Am
%%score (T1 T2) (B1 B2)
V:T1           clef=treble
V:T2           clef=treble
V:B1  middle=d clef=bass
V:B2  middle=d clef=bass
%            End of header, start of tune body:
% 1
[V:T1] "♯vii°⁷"">(↓)"b,   "i"a,
[V:T2]    f,    e,
[V:B1]       d,    c,
[V:B2]    ">↑"^g,,    a,,

but this whole step down has rather less impressive leading character than a half-step, as here in the diminished seventh chord both the bass leading upwards and the alto leading down to the tonic's fifth.

The tonic's third can also be approached from a semitone above

X:1
L:1/4
M:
K:A
%%score (T1 T2) (B1 B2)
V:T1           clef=treble
V:T2           clef=treble
V:B1  middle=d clef=bass
V:B2  middle=d clef=bass
%            End of header, start of tune body:
% 1
[V:T1] "V⁷"g,    "I"a,
[V:T2]       e,    e,
[V:B1]     ">↓"d,    c,
[V:B2]      e,,    a,,

But how about the root – can this only be approached either from a semitone below or somewhere more distant? There are of course the augmented sixth chords, but these always seem to have secondary dominant function, and don't directly establish a tonic.

X:1
L:1/4
M:
K:Am
%%score (T1 T2) (B1 B2)
V:T1           clef=treble
V:T2           clef=treble
V:B1  middle=d clef=bass
V:B2  middle=d clef=bass
%            End of header, start of tune body:
% 1
[V:T1] "viIt⁺⁶"a, "V"^g,    "i"a,
[V:T2]         ^d,     e,    e,
[V:B1]       a,,       b,,    c,
[V:B2]    ">↓"f,,      e,,    a,,
  • Neapolitan sixth could easily go to the tonic, with the tonic commonly in 2nd inversion before hitting the dominant. – thrig Sep 4 '16 at 15:53
  • @thrig: interesting, the Neapolitan seems indeed to work without properly going to the dominant first. Could you elaborate how the voices should be lead in that scenario? – leftaroundabout Sep 4 '16 at 16:07
  • @thrig When the Neapolitan goes to "tonic in 2nd inversion," that's not really a tonic chord, it's the dominant with a 6th and a 4th above it that needs to resolve to a 5th and a 3rd. Otherwise known as a "cadential 6/4." Most theorists just call it a dominant function chord, some occasionally call it pre- or subdominant, but it's never tonic function. – Pat Muchmore Sep 4 '16 at 22:43
  • And old question, but are you still interested in this? And are you looking for just chords that are based on the root or any chord that includes a resolution from the flat second scale degree to the tonic? Also, are you interested in minor keys or just major? I can think of quite a few examples in real music if you're interested still. – Some_Guy Aug 27 '18 at 21:52
  • @Some_Guy I'm looking for any ways to harmonise a ♭Ⅱ-Ⅰ movement in a melody, such that the Ⅰ note is given a sense of finality. – leftaroundabout Aug 27 '18 at 22:00
5

The classic example of a root being approached from a semitone above is when using the "tritone substitution" or "b5 substitution" for a dominant-function chord. In the example see how the F - B tritone is retained, giving Db7 its "dominant of C" quality, and how the parallel 5ths don't hurt the ear at all in this type of chromatic harmony. You're slipping a Db triad down to a C triad - revel in it!

The idea of b5 substitutions also opens a door to understanding how the Augmented 6th chord works. Look at it as a b5 substitution for ii7.

enter image description here

  • Ah, yeah, the Italian augmented sixth. But I just can't feel the C after that D♭⁶⁺ as having tonic character – it always seems to lead on to F-minor. Does it perhaps need a Jazz context with extra notes to avoid that secondary dominant feel? – leftaroundabout Sep 4 '16 at 16:22
  • s/Italian/German/ – leftaroundabout Sep 4 '16 at 16:29
  • 1
    @leftaroundabout I think if you establish a sense of C major, then shift to a bunch of I–ii–V7–I progressions and then suddenly replace the V with bII7 (the TT sub is usually written as a dominant 7th, I think Laurence wrote it as an +6 to emphasize the notes held in common between it and V7) it might work better. I–ii–bII7–I has a very convincing chromatic bass line and resolution of ^7 and ^4. Also, you might want to look into Phrygian and (to a lesser degree) Locrian for other contexts with a half-step downward resolution to the tonic. – Pat Muchmore Sep 4 '16 at 22:55

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