The core of jazz is improvisation. This is also what sets apart jazz music from many other forms of music. A friend of mine, who is a keen composer, once asked me, "Don't you jazz musicians get bored playing the same standards all the time over and over again," and I replied, "Well, the thing is, everytime we play, it is different from the last, and we seldom know what's going to happen next."
Check out this video of some great musicians jamming away at casino lights '99 Montreau Jazz festival. I doubt that they've rehearsed this song more than a few times and that what they played was what they rehearsed. Notice the frequent signaling between musicians.
Notice also how each of the musicians was one by one soloing over the same chord structure. Improvising a melody is a key factor in determining a jazz musician's musical prowess. But there are also many ways to improvise. I remember the old days when I first started playing jazz. While the chords were moving, my head would be formulating all the possible notes that I could play, based on the chord/scale relationship chart. And my fingers would be running up and down the keys based on whatever notes that are possible for me. Who knows, sometimes I might get some really fast, jaw dropping, nice licks. BUT THAT'S NOT JAZZ...
THIS IS JAZZ....
I'll bet you that Earl Hines hears every note that he is about to play before he played them. It is only when you achieve such "imaginary hearing" that you will be able to truly enjoy the pure joy of jazz piano playing the way he did.
"Only play what you hear. If you don't hear anything, don't play anything." It wasn't until after a few years of extensive listening and playing jazz that I learned to understand what the great jazz pianist, Chick Corea, was really saying. Well, the first question a beginner would be asking is, What should I be hearing? 'Cause if I don't hear anything, how am I to play anything? This issue can best be tackled from the perspective of a scat artist.
Check out this video of Ella Fitzgerald, demonstrating her amazing scat singing techniques. And perhaps you should know that Ella confessed in an interview that she never received any formal music education. Well, William Hung confessed to the same thing too on national TV. :)
This clearly shows that the human brain is able to create, and improvise melodies to fit the harmonic structure of a piece of music. Just play a few chords on your piano. I'm sure most of you can straightaway feel a melody coming out of your head that fits the chords you are playing, although you may not know what the notes of the melody are at all. However, without well trained ears, your melody might only be dwelling around a major scale or just a blues scale, because that's what we all hear day in and day out on the radio and everywhere. Only when the brain is frequently "fed" with attentive listening to more complex harmonies and melodies, will it try to imitate or emulate, and thus create complex improvised melody lines. And this process is thoroughly explored by jazz musicians. Before we move on, check out this video of Bobby McFerrin, another great scatter.
Now that your head is filled with melodies, the next question arises: how to turn imagination into reality. Or in plain English: how to play on your instrument what you hear in your brain. The solution lies in proper ear training. Yes, your ears are the bridge that connects your brain and your fingers.
Many musicians will go all the way to demonstrate that they're "pre-hearing" every note they're about to play, by scatting along in unison with what they're playingproof that the player is not just running scales with his fingers, or just executing a lick that has been learned beforehand. Guitarists often do that kind of "singing" while they're playing, while sax and trumpet players don't have the luxury of doing it.
Some musicians also "sing" unintentionally when they are deep into their solos. It is undeniable that they too have good pre-hearing capabilities, but the control of their vocal cords is another story. That's why some people would call it grunting instead of scatting, some just call it pure noise. Keith Jarrett may be the "master" of that.
But many jazz tutors are encouraging their students to hum along with the melody they are improvising. Besides training your ears, it also helps build solo lines that are more melodious. However, there is another school of teachers who strongly believe that humming along would be a distraction for students. Neither side has been proven right or wrong...