The goal of the jazz accompanist is to outlining the given chord progression clearly while complimenting the soloist's ideas. As we know, most jazz improvisations use and outline the harmony as a foundation for melodic ideas. (See jazz improvisation.)
This chord progressions series demonstrates the most common progressions found in jazz. They will help you hear and understand the recurrent harmonic traits found in traditional jazz repertoire.
Modulation is the concept in which we change the "home key". This new tonality becomes the point of reference momentarily or permanently. In tonal music, any key center can be modulated to.
How about a fermented fifth modulation in K sharp fridgemyan? (-;
The IV chord being the closest related tonality (in relation to the I key) it is the most common "destination key" in classical and jazz music. Loooots of jazz standards incorporate a modulation to the IV.
Let's use a little imagery to describe this :
We're staying home tonight :
I (home); II (away); V (further away...); I (home).
As in C, Dm7, G7, C.
Tonight, let's hang out with the neighbours :
I (home); II (...); V (...); I (home???); IV (at the neighbours).
As in C, Dm7, G7, C7... F!
It seems like human ears like this friendly neighbour that is the IV! When the modulation is established, we feel "like home" almost immediatly.
Let's look at a musical example to clarify all this. Play the following progression on the guitar:
[This type of progression can be found in the
standard tune "Cherokee" by Ray Noble and in many, many, many others songs!]
As you can see and hear, the I chord becomes dominant right before going to IV. This is the heart of the modulation. You can also notice the IV minor right before going back "home" to the I.
I will not go into theorical details here; if you are interested more in harmony look up this cadence article in my "No Nonsense Guide to Jazz Harmony".
Bluesy Modulation the IV
Believe it or not, the very common blues progression contains a modulation to the IV key. The I chord is obviously dominant right before going the IV (It's a blues!). Here it is :
Try embellishing the fourth bar of the blues with some alterations (such as b9, #9, b5 and #5). It creates a tension that is released when establishing the IV (as in C7(b9) to F7). Here's that jazzier blues :
It is even possible to use a II-V-I in the key of the IV to create an even clearer modulation in bars 3, 4 and 5. To go to F, we use Gm7-C7 :
Study the blues progression. It is worth more than you might think at first.
Listen to Oliver Nelson's "Blues and the Abstract Truth" (1959, Impulse).
oh... and I almost forgot to mention : check out the "bird blues" progression. It's a common thing that Charlie Parker played a lot on during the bebop era. Listen and play tunes such "Blues for Alice", "Chi Chi" and "Freight Trane".