dominant chords
The dominant chord is the most important chord. Hence the name. But you may be wondering:
what’s so important about it?
The dominant -> tonic (V->I) progression is really the foundation of western harmony. The classical theory term is authentic cadence. It’s importance stems from how it’s used to set an expectation of what is to follow. The usual thing is a tonic chord. But a lot of interesting music happens when expectations are violated.
Le Mystère Des Voix Bulgares is a superb example of how alien (but still utterly beautiful) music can sound when the authentic cadence is avoided. And it’s not so much a conscious avoidance here as it is drawing from a tradition where the cadence is not so pivotal. Tension and release are still created, very much so. It’s just that the music does not use cadences to do it.
Check it out (3 excerpts in this clip):
So, without completely avoiding the dominant, western music still offers a number of formulas that exploit the violation of an expectation of resolution for effect. Drawing from classical theory, the deceptive cadence (V->vi) is a nice example. vi shares chord tones with I, so it voice leads much the same as V->I does. Even the name gives you a sense of the fake out that occurs when you hear this. It’s deceptive in that you are expecting a different resolution.
Key changes can accomplish the same goal. A modulation upward surprises you by setting up an anticipation of a resolution, then avoiding it consciously for heightened tension. Setting up the new key usually involves playing its dominant chord first.
Bebop draws heavily on a device called sequencing, where a musical passage is repeated at a different pitch level. Sequences of ii-V in descending semitones and descending whole steps are pretty common in bop.
Whenever you run into a chord that’s notated as a diminished 7, you should usually expect it to function as a dominant. The root won’t be the notated root though, so your clue as to its function should come from the subsequent chord.
The fourth and seventh degrees of a major scale form the seventh and third of its dominant seventh chord, respectively. For example, for C major, the IV is F, the VII is B. B is the third of G7, and F is the 7th. Some important things about this relationship:
- This interval is a tritone. It is six semitones, or the equal division of an octave into two parts. This symmetry will become very important as we examine substitute dominant chords (in a future post).
- The tritone only occurs in the major scale at this position.
- The inversion of a tritone is a tritone (which follows from 1 above)
- The third and seventh of a seventh chord define its quality.
- The only seventh chord to contain a tritone is the dominant seventh.
- The major scale’s seventh degree wants to resolve upward one semitone to tonic (hence the name leading tone).
- The major scale’s fourth degree resolves downward one semitone to the third degree.
Ok, to recap: the dominant sets an expectation of the following chord. But that expectation also relies on our acculturation. And furthermore, you don’t always get what you expect in music. That is part of the fun after all. Hopefully, you’ll know a dominant next time you meet one, and I expect you won’t have to wait long to encounter the next one.
Nice post! These articles are amazing. Can you elaborate more on the topic of ‘Modulation’. I hear it mentioned casually quite often and I understand that it refers to movement to a different related key but thats all I know. What kind of relationship do these keys have and is the dominant chord that you use to set them up in the original key?
Do all songs have modulations in their orginal form or are they usually added to give color and variation to the piece? (ie: It says in the liner notes of his solo album, Alone, that Bill Evans modulated to several different keys all while he performs the same song, Never Let Me Go. I also remember reading Larry Grenadier saying that one of the reasons playing with Brad Mehldau was a challenge was b/c Brad was always ‘modulating’ in the middle of the song)
Comment by whitecraneboxing — October 26, 2006 @ 2:50 am
It sounds like you understand modulation quite well already. It’s just the movement to another key center within a song. It can be a temporary or permanent modulation. The permanent “key change” sort is kind of a cliche in commercial music (for a gleeful celebration of this, refer to http://www.gearchange.org/).
The key here, and sorry if I was unclear in the article, is that the modulation is set up by introducing the dominant chord of the new key. This is especially true of the gear change version.
Modulations can happen as a part of the original form, like how “I Love You” has a phrase that modulates up a major third. But as you learned from Mr. Evans, the performer has discretion as well. It is a dramatic effect, even if it has been extensively abused (a mentor of mine used to say “a cliche is a cliche because it works.”)
Brad who? (just kidding, please don’t smite me O music gods)
Comment by Rob — October 26, 2006 @ 6:38 am
Are there any ‘rules’ for what key modulations sound better? Or when to insert them during a melody? Do you modulate back to the orginal key with a dominant chord that goes to the I of the original key, or can it be any maj chord ? Thanks Rob!
Comment by whitecraneboxing — October 26, 2006 @ 12:03 pm
So the copout answer is hell no there aren’t any rules, this is jazz. But it’s more subtle than that really.
I can probably find you an example of standards modulating into every possible key if I work at it long enough. So from the point of view of the composer, it’s pretty wide open. For modulation at the initiative of the performer, the typical thing is going up, and by small distances. The more daring go up by larger distances. Hardly anyone modulates downward.
So of course, I had to do it just to be perverse when I recorded ‘Round Midnight for Youtube.
And to your question about getting back home again, if you go up by an even number of semitones, there’s always a circle-of-fifths path back to tonic. Not a rule, just an observation.
Some people play On Green Dolphin Street in C, some in Eb. We used to split the difference by playing the first half in C and the second in Eb. Because of that, the last bar of each section had to belong to the key of the next section, not to the key of its section. Does that make sense?
It’s not about where you’re at, it’s about where you’re going.
Comment by Rob — October 26, 2006 @ 1:17 pm