C7 - Ab maj resolution

Question

I came across this resolution while listening to Ambiguity by Rainie Yang (starting at 0:47). The chord progression here is in Eb major. This is what I hear:

Eb - Bb - Bbm - C7 - Ab - Eb - Fm - Bbsus4 - Eb

The second thru fifth chord is where I'm getting confused. The Bb - Bbm - C7 seems to tonicize F, and C7 as a secondary dominant in F I would expect to resolve to some flavor of F or D(b). As a big stretch, I can read it as a version of V - vi in the key of B, where the V is substituted for its tritone dominant and the vi is substituted for its parallel major, but this feels like the kind of reading Occam's razor would shave away. On the other hand, I could just call it "chromatic mediant" and move on, but that seems like a cop out.

The resolution sounds natural and, while I can't think of any examples right now, I feel like it's not uncommon, which leads me to believe that there's probably some name for what's happening. Does anybody know what it is, and possibly some other examples of this kind of resolution?

Answer 1

First, look at the bass line. Before listening to the song I anticipated this would be it, and I was right! A descending scale, down to a dom7 type chord, then another descending scale to a standard ii - V - I cadence. Scalic bass lines are strong. Imitation is strong.

Then there's the slightly unexpected resolution of C7. Yes, Fm would be the obvious choice. But it goes to the relative major of Fm instead. That's about as unremarkable as a 'substitution' can get, made even less remarkable by A♭ being a primary chord in the prevailing key.

All very standard, made interesting by two slight deviations from the obvious - the Fm - A♭ substitution and the B♭sus (or is it actually A♭/B♭) penultimate chord.

You want a name for this? Well, it's not 'borrowing' or 'modal mixture' because A♭ is about as diatonic as you can get in the key of E♭ major! 'Substitution' is the technique used. But really just 'composer's choice', unless we're going to label anything but a simple 'cycle of 5ths' progression as remarkable!

Answer 2

First, one of the things that makes this progression work so nicely (although it’s not necessarily relevant to answering this question) is the inversions of the chords, which you didn’t include:

Eb Bb/D Bbm/Db C7 Ab Eb/G Fm Bbsus Eb

The progression is in Eb and the C7 is a V/ii. Instead of a ii (Fm) it goes to a IV (Ab) and two chords later gets to the ii chord. IV and ii chords both have a subdominant quality and share two of 3 notes. I think of this as either a delayed resolution to the ii chord or a deceptive cadence of sorts since ii and IV have a similar function.

I know I’ve heard this chord relationship in the past, I just can’t think of any examples off the top of my head. If I do I will add them in an edit.

Answer 3

There's nothing special about going to Ab instead of Fm. Maybe there's a name for it, but I'm not good with names, it's easier to think of progressions in terms of what they do and what chords they consist of.

I see three things about the chords you ask about

• During the first four chords, there's a descending chromatic motion Eb - D - Db - C. You could emphasize that by making the chords Bb/D and Bbm/Db, with D and Db in the bass: Eb - Bb/D - Bbm/Db - C7. (Edit. Ok, seeing John Belzaguy's answer, that's what the song actually does)
• The Bbm - C7 chords make you think it's going to do a secondary dominant motion to Fm. When you're in Eb or Cm, the chords Bbm - C7 (or Bbm6 - C7 or Gm7-5 - C7) are commonly used as a two-phase secondary dominant springboard to Fm. You could use just C7, but preceding it with Bbm (or Gm7-5) is an additional booster.
• If you prepare a dominant-tonic motion to a minor tonic, you can instead opt to go to the relative major tonic instead, and then it will just sound like "ah it went to the relative major instead". Here's an example in Fm or Ab that seems like it's going to Fm, but it goes to Ab instead.

You can do that, and it sounds like what it sounds like.

In the example progression you listed (I didn't listen to the song), the things are combined - a secondary dominant motion to a minor, but going to its relative major instead. It seems like going to Fm, but unexpectedly it goes to Ab. And it does this so that Eb feels like the real tonic. How unexpected this really was, it depends on what you expect. Maybe by the time you get to the C7 you're like "OMG it's not going to do this cheezy grandpa music jump!!? I have to press stop quickly before my friends hear this, because it's going to be soooooo embarrassing if it goes to Fm." And then you're relieved to get the Ab instead, retaining at least some level of credibility among your social group.

There are so many different ways to combine chords, if you wanted to assign a special name to every useful trick, you'd need to learn a lot of special names to know what you're talking about. Instead you can list the chords.