What does it mean when progression is resolved?

Question

I saw this text inside a very basic piano workbook in which I'm not sure what the author means by using "resolve".

Progression #1: C-F-G-F-C

NOTE: This 4 bar progression resolves back to C after the final time it's played on the play along CD.

Dictionary.com gives this definition for "resolve" as used in music:

Resolve: [Music] to progress from a dissonance to a consonance.

But the problem is that I don't here any dissonance on the above progression. C, F, and G totally sound harmonic and simply good!

Answer 1

Try playing a sequence C - F - G - F in a loop. Think of it as the basis of a song. This is probably what you'll hear on your play-along CD.

Now see what happens if you simply stop after the final F.

Most people would agree that it hasn't ended properly. It's hanging; the listener expects something else. It is unresolved.

Now try ending by adding that final C after the last F. Now it sounds as if it's finished.

Because the sequence starts with a C chord, and because all of the chords use notes from the C major scale, C feels like the "home" chord.

When you move away from the home chord, you introduce a tension - not a dissonance -- and when you return to the home chord, you resolve that tension.

Some pieces defy expectations by ending on an unresolved chord. But if your aim is to make the listener comfortable; to have that sense of closure; then resolving to the home chord is the conventional thing to do.

Answer 2

"Resolution" has a slightly broader definition than just "from dissonance to consonance." Before I get to that, though, I want to touch on why exactly that definition is used.

First, let's throw out the chord progression you supplied: it's very 60's doo-wop, and not a good example for common practice harmony. Let's replace it with |: C F C G :| C (I am using |: - :| to indicate repeats.)

We are playing in the key of C major. This is clear from the fact that we start and end on that chord, and all of the other chords contain notes within the key of C major. This means that our C chord is called the tonic chord. It functions as a "home base," if you will. In common practice harmony, a dominant chord is one that implies a following resolution to a tonic chord. There are many other names for different chord functions in a key, including mediant, sub-mediant, sub-dominant. I am only going to focus on dominant and tonic here, so you should know that we use I (Roman numeral one) to refer to the tonic chord built on the root note of the key (C), and V (Roman numeral five) to refer to the dominant chord built on the 5th note of the key (G).

Back to our progression. Let's change it once more, to |: C F C G7 :| C. With Roman numerals, we would use |: I IV I V7 :| I. This is where we get the dissonance that your original definition was talking about. The V7 chord is called a dominant 7th, because it contains a tritone that strongly implies a resolution to the tonic chord. (The dissonant tritone is caused by the 7th chord member, in this case, F.)

To exemplify this, play G7 as follows: G - F - B (from the bottom of the chord to the top). The F with the B above forms a dissonant interval of a tritone. It should sound odd and unstable. To resolve this chord to our consonant tonic chord of C, move the B up half a step, move the F down half a step, and move the G down a 5th to C. We are resolving the dissonant tritone outward by half-step to our consonant tonic chord.

So, that's essentially where your resolution definition is coming from. Now, let's bring it back to your original example step-by-step.

If we consider G - C in C major (V - I), we don't have a dominant 7th chord to fuel our resolution, but it really isn't necessary. If the entire piece has been in C major this whole time, the listener is going to expect the piece to end on the tonic I chord. We call this ending a cadence, essentially meaning a kind of chord-to-chord resolution. The V chord (G) still has dominant function in the key of C major, so we can say we are resolving to C, EVEN THOUGH the G chord IN ISOLATION sounds like it doesn't need to go anywhere. Context is incredibly important in music theory and analysis.

Now, back to our original example of |: C F G F :| C, or |: I IV V IV :| I. The cadence we are analyzing is IV - I, or F - C. We are still in the key of C major, so the ear is going to expect the piece to end on the I chord, C. We can call it a resolution from F to C because the ear expects this in context. The IV - I chord progression actually has a special name: the "Plagal cadence". It is easily remembered since it is commonly used to set the text "A-men" at the end of hymns.

As slim alluded to, a better definition for "resolution" might be a "release of musical tension". Dissonance causes musical tension, as does moving away from the tonic "home" chords. The tension is then released by resolving back to the tonic.