The dominant chord provides movement in tonal music : it's tendency to resolve (aka "to go somewhere else") is very strong. It has an even stronger harmonic pull when the seventh is added on top of it.
The dominant seventh is used most of the time in jazz music. If you look at sheet music or in fakebooks, dominant seventh chords have "just a number" so to speak : they're identified with "7" (or "7th"), "9", "7(b9)", "13" or "13(b9)" and "dom7" and so on.
In this series we will look into the most common colors for the dominant chord. I like to approach them by their respective sound, starting with the most consonant and moving towards more alterations of the basic sound.
Please note :
All examples will use a G dominant chord throughout this article series. I chose this key because it resolves back to a C (which the basic key of reference ... or "the people's key" as a good friend likes to call it!)
Jump to a page :
Dominant Chords Introduction [You are here]
Dominants Part 1 : The Basic Sound - Mixolydian
Dominants Part 2 : Mixolydian with a flat 13th (mixo b13)
Dominants Part 3 : Mixolydian with a sharp 11th (mixo #11)
Dominants Part 4 : Mixolydian with a flat 13th and 9th (mixo b13 b9)
Dominants Part 5 : Super Locrian (or altered scale or Dim Whole-Tone)
Let's get started with a little theory refresher...
In classical terms, the dominant chord is built on the fifth degree of the scale. In C major, count ...1, 2, 3, 4, 5 ... it's the G chord!
The G chord (dominant) leads naturally to the C chord (tonic). It's a movement up a fourth (or down a fifth). This "V - I" chord progression is called cadence.
The urge to resolve the "V to the I" is greatly enhanced by the presence of a seventh on the dominant chord. Instead of being simply G-B-D, the added seventh gives us G-B-D-F : dominant chord jazz

As you can see, there is a tritone created by the added 7th (between F and B). The two notes in the tritone are the most unstable of the major scale : the 4th degree (F) and the 7th degree (B).
In short...
So the traditional "V7 - I" cadence is G7 (G-B-D-F) going to C (C-E-G) and it looks something like this : dominant chord jazz guitar

There is much, much more to know about proper voiceleading and classical harmony but it's not the focus of this article. Simply remember that...
So, whatever happens in the theory books, the dominant chords will not always resolve back to the tonic... that is where the fun begins!
In jazz, the dominant is not only a "tension - release" workhorse, it also serves the composer and improviser as a coloristic tool. The dominant is, nowadays, just another musical way of expressing human emotions.
That is how I approached writing these dominant scales / chords articles : by color (jazz), not just by proper resolution (classical). You can (and should), of course, try resolving everything to the tonic...
...but you should first and foremost hear the different personalities of the dominant "colors" on their own.
When reading and playing through the fololwing articles, imagine (or record and play-along) a drone-like coloristic fermeta for each individual types of dominant chord.
The different dominant sounds have their own textures.
The many types of dominant colors discussed in the following articles should become your best friends. Respect them, hang out with them and learn to recognize them when you hear their voice (!)
Of course, all the dominants you will encounter should be practiced thouroughly. You want to have them ingrained in your ears and fingers.
Here are some points to keep in mind when internalizing the different dominant chord colors : (or any type of chord for that matter)
then... Improvise on that chord / scale!!
On top of that, in each individual article, the dominant sounds are explained and demonstrated with specific applications common to the tradition of jazz. (tunes, progressions, turnarounds, blues, etc.)
...so don't worry. Their will be plenty of practice suggestions for you to "get into" the new sounds.
By all means, do not keep the reference the "theorical origin" permanently (ie mixo is fifth mode of major)... It will slow you down in the long run; here's what I mean :
It may be tempting to learn mixolydian by always refering to its "parent" scale. For example, you may see F7 and think "Bb major scale" or see A7 and think "D major scale".
A little advice : don't do that!
The major scale and the mixolydian mode (built on the fifth degree of major) have completely different personnalities (even if they contain the same exact notes). It's a matter of what function they fulfill in the music.
While it is important for you to understand the relationship (ie where the mode is coming from), it's a very bad idea to improvise on F7 mixo the same way you would on Bb major...
If you hear an orchestra, a band or an improviser play on a dominant chord you will hear stuff that is specific to that chord. (Not generic stuff that "fits" all the modes of the major scale!) Great musicians can see the relationship but will always treat the harmony as it is.
That holds true for all modes that you may be using "in reference to a parent scale" all of the time... get rid of that habit if you fell into it! Learn mixolydian for what it is.
Have fun... and dominate well!
Jump to a page :
Dominant Chords Introduction [You are here]
Dominants Part 1 : The Basic Sound - Mixolydian
Dominants Part 2 : Mixolydian with a flat 13th (mixo b13)
Dominants Part 3 : Mixolydian with a sharp 11th (mixo #11)
Dominants Part 4 : Mixolydian with a flat 13th and 9th (mixo b13 b9)
Dominants Part 5 : Super Locrian (or altered scale or Dim Whole-Tone)
Jazz Guitar Chords and Jazz Harmony