Tuesday, September 05, 2006

Bitonal Concepts in Jazz

Tom Gullion - Jan '97

While studying at Indiana University, David Baker opened many doors for me. From private lessons, his compositions and playing in his small group (the "21st Century Bebop Band") I was exposed to a LOT of bitonal/pantonal music. Here I will give a brief introduction to bitonality and share some insights I've gained along the way.

David Baker has many excellent books on the topic and David Liebman also has a very thorough book ("A Chromatic Approach to Jazz Harmony and Melody" Advance Music, 1991) that covers a lot of this material.

Though the definitions haven't seemed to finalize yet, bitonality is basically music characterized by the mutual coexistence of two tonal centers. Bitonal music thus offers the musicians two separate, yet interacting, harmonies to draw from. Although the nomenclature is the same, bitonality differs from pedal point. Pedal point is just a chord/scale played with an alternate bass note. Consider the following example:

example 1

Note that the C/Ab symbol can denote either a triad over a bass note or a triad over another triad.

In pedal point, the improvisor would play a C major scale over an Ab in the bass. He/she could either include Ab in the C major scale or ignore it. In bitonal music, an improvising musician may play from the C or Ab major scales, or as we'll see later, a combination of the two. In this article, we will be dealing with bitonality, not pedal point.

When first exposed to bitonal harmony, it is difficult to simultaneously think in two keys. Sometimes it helps to distill a scale from the two chords. By playing the chords on the piano or arpeggiating them on your instrument, you can usually determine which notes are most important and create a scale from the resulting notes.

You might choose a mode of F ascending melodic minor to play over C/Ab.

example 2

While finding a scale that approximates the chord sound is helpful it doesn't really open you up to the inner beauty of bitonal music. Playing off the sound of the chords is often a very rewarding experience that brings out musical ideas you may not have otherwise considered.

There are many approaches to practicing these chord/sounds. Given the above example chord (C/Ab) one could practice in the following manner. First I would definitely play the chord(s) on a piano and try to internalize the sound of the chord(s). Playing the two scales (C and Ab) simultaneously (by alternating between the two scales) is also very effective and a good intellectual exercise as well. For example, play the two scales alternating:

example 4

Another approach is to assign scales to particular ranges (usually octaves). For example, from C3 to B3 play C, from C4 to B4 play Ab, and so on. Yet another is to create a "hybrid" scale that best represents the sound to your ears. It could be an altered diatonic, pentatonic or whatever scale you dream up. Woody Shaw was a master at this.

Often, through this type of practicing, you will make many discoveries such as licks, phrases and/or harmonic insights. Try to stay open to these because these discoveries are what I find most exciting and interesting. Many of these can carry over to your "straight-ahead" harmonic conception and may just give you that fresh sound you've been striving for.

One of my "pet" bitonal concepts that has proved useful in all kinds of music has been the relation between chords stacked at the interval of a major third. There is a simultaneous consonance and dissonance that really opens up a lot of possiblities for me. This, of course, is nothing new. Just consider the bridge to "Have You Met Miss Jones" or the Giant Steps cycle. Giant Steps has just three basic tonal centers: B - G - Eb. With some experimenting at the keyboard, you'll see what I mean. Playing any two of those chords (just as triads for simplicity) will show you where the consonance/dissonance lies. Each chord has a common tone but introduces two half-step clashes. But yet, to my ear, there is a very settled, consonant sound. Consider the following example:

example 3

Note the symmetry between these stacked chords. These make for some interesting lines.

There are many more symmetrical licks like that one that might be worth exploring. There are also lots of altered pentatonic possiblities as well. With this music you really take note of the endless choices available.

Hopefully this will provide some inspiration for you. Personally, bitonal harmony really opened up my playing and showed me a lot about how to control dissonance. When you get right down to it, controlling dissonance is what improvising is all about. All those incredible musical moments occur because of the constant struggle toward resolution. Effective manipulation of consonance and dissonance makes your music more powerful and more meaningful. Just like life.
StumbleUpon Toolbar DiggIt! del.icio.us

2 Comments:

At 1:41 PM , Anonymous Anonymous said...

Nice ideas, however I would like to correct an error. A bitonal chord (two chords stacked upon each other) is not the same as a slash chord (Triad over Bass Note).
Slash Chords are notated as follows: Bb/C with a backslash or slanted line between the two chords.
Bitonal chords appear stacked directly atop one another with a line parallel to the staves of the sheet music.

 
At 2:43 PM , Blogger Tom Gullion said...

I don't really agree with that convention. I'm certainly aware of it. I find the stacked notation cumbersome and unnecessarily difficult to maintain in notation software programs.

What I tend to favor is actually spelling out voicings in my compositions if I'm looking for a particular color.

 

Post a Comment

Links to this post:

Create a Link

<< Home