# Why do these progressions sound good?

I have always wondered why these progressions sound so exiting. I don't really know how the I-IV-things work, so I'll just write the chords. An explanation of what's really going on would be much appreciated. Why have they been used together? Can you in some way show (an possible explanation of) why exactly C comes after Bb in the first progression and so on?

1. Bb - C - A - Dm As seen in Karazhan (0:29)

2. Am - C - D - F As seen in House of the Rising Sun

• "Good" and "exciting" are really subjective, and I'm not sure this doesn't stray too far into psychology. – user28 May 31 '12 at 18:56
• @MatthewRead I've tried to clarify now (see edit) – Johannes Lund May 31 '12 at 19:10
• Ah I see. The "why was this composition choice made" angle is better. Perhaps it's speculative but it probably has an interesting answer. – user28 May 31 '12 at 19:13

Well, the I-IV thing is in a sense problem-complete of the question. It shows the relationship of the chords to the tonal center (the key). So we have to do some harmonic analysis just to do this translation.

I'll do House of the Rising Sun because that's the one I know. The Am is the root chord i (but the proof is really in the second and fourth lines of the progression with the V-i movements). The next chord C is a mediant III. The next chord D is a fourth IV. Then the F is a curveball, because we just heard an F♯ in the D chord. It's called a chromatically-altered mediant ♭VI, and it produces a little bit of excitement by jumping out of the frame of the scale established so far. Before the F, we're in A Dorian Minor. Then we're in A Natural Minor. But by the time the E7 V7 comes around, we're in Harmonic Minor.

This shifting about of scales is part of the excitement.

Another aspect, exposed by leftaroundabout's answer (with which I entirely agree), is delaying the "cinching" of the tonic. You can't really be sure what the key is until you follow the whole thing with its twists and turns and see where it's driving at.

One rule of thumb which appears to work with both of these examples (and with most Western Tonal Music) is to look for the V-I or V-i (if it's minor). The V chord is often very strong when it enters, and the rules of counterpoint indicate how the trapped tritone wants to resolve. If it resolves "correctly" to I (or vi, in a deceptive cadence) then you can be fairly sure you've found the key.

Both progressions contain two subsequent major chords, the first one one whole step below the second. That step is classically reserved for IV - V, as in the cadence I - IV - V - I; and classically, it's among the most "mandatory" things that after this V there be a I. But in both examples that's not what happens! In Karazhan, Bb - C would in fact be the IV - V to the major key F which is parallel to the actual key Dm, but putting the dominant of latter right after the dominant of the former rather than first resolving to F still puts in some extra excitement, aided by the half-note step C-C♯ between those two dominants.

In House Of The Rising Sun, C - D isn't actually IV - V at all but III - IV, but if it wasn't for the F thereafter you might well believe the key to be G. That would perhaps be perceived as something of a disappointment: you start at Am and certainly think it's i, then you go to the pleasing if somewhat premature major parallel III. Then this D comes around and disrupts the peace, which stirrs interest but also hints that the actual key might be G, with the rather more boring progression ii - IV - V - I (Am - C - D - G). Instead, the F comes around, which not only has a semitone step difference again to D (F♯-F in this case) but also, in a way, "saves the day" by restating Am as the actual key.

All a bit speculative, but I suppose that's inevitable for such a question.

Just as a note, these chord progressions are not universal at all times and in all cultures. In the 14th century the Landini Cadence was the thing. Play a chord of G, B and E. Hold the G and B but move the E to D. Now play F C F (no A). That was the way to end a song.

To us it sounds weird and unsatisfying. We like our IV - V7 - I. To them the V7 chord (G - B - D - F) sounded horrible because of the F - B tritone. Even the C - E - G triad was a dissonance to them.

My point is that there probably is nothing inherent in human psychology (separate from culture and experience) that makes your examples sound exciting, and you won't find an answer looking there. It must be that they sound to us the way they do because of the background of everything we've heard before.

• Their instruments were tuned differently, which is why C-E-G sounded horrible whereas it doesn't in more modern tunings. It's not just psychology, there was also a physical reason. – Raskolnikov Jun 2 '12 at 21:08