Quick Music Theory Question

[InsigTurtle]

I was just wondering.
I noticed that while iii6-I sort of works, but it doesn't sound as "final" as V-I. I suppose that changing iii6 is pretty much V13 without an F, but whatever. So other than the standard stuff like bII7, vii^o7, and V7, what else could you use that has a dominant function? Why doesn't the chord G-B-Db resolve as nicely to C?

[Altissimo]

Two that I know of that work okay for dominant functions are #Idim (ex. CEG -> C#EG -> CEG) and iv-I.

[InsigTurtle]

Hmm, yeah, IV-I and iv-I are nice.
I've been experimenting around a bit, I'm a bit surprised that the Petrushka chord doesn't really work too well for a dominant chord, in my opinion.

[Pianist Da Sootopolis]

The Petrushka chord doesn't resolve well because, as Stravinsky likely intended, it's quite dissonant.
As for your specific chords, a iii6 in a major key is the same as the tonic major seventh. For instance, in C, the iii is e minor, and adding a sixth onto that creates a chord that is spelt E-G-B-C; harmonically the same as a C major seventh.
IV-I/iv-i works, especially in religious music (hence the plagal cadence's nickname the "Amen cadence").
@Alti Wouldn't that progression just be to C- Csus4? C, E#/F, and G form a sus 4...
I don't have any of my own, in all fairness, but the issue with adding in random notes is they either become harsh dissonances or they just become inversions of other chords. At least, that's what I've found.

[InsigTurtle]

Oh, I meant iii6 as in iii first inversion, so G B E. The way I learned it uses 6 short for 6/3, not as an added tone. I'd've spelled it as I6/5 if I meant E G B C.

I don't really see a problem with harsh dissonance if it's used effectively and in the right context. But I digress. I don't add random tones, but rather, replace or alter them. So stuff like V7b5 and V7#5 works (and sounds quite nice, relatively speaking).

[Bespinben]

I quite like iv6 > I. It makes a good "bittersweet" cadence. Think Bubbles Shining Over the Sea.

[FireArrow]

For major keys iv diminished works really well.

Why doesn't the chord G-B-Db resolve as nicely to C?

It resolves nicely to C minor.

[Altissimo]

@Alti Wouldn't that progression just be to C- Csus4? C, E#/F, and G form a sus 4...

Wrong notes - C#, E, and G, not C, E#, and G.

I quite like iv6 > I. It makes a good "bittersweet" cadence. Think Bubbles Shining Over the Sea.

And the end of the SM64 credits, except that's root position (and SPELLED WRONG IN THE SHEET ON SITE, I THOUGHT THAT WAS SUPPOSED TO BE FIXED)!