The Density Referent in Jazz Improvisation


Young woodwind players (jazz saxophonists especially) often ask me how to develop the ability to “play really fast.” The truth is that playing fast is meaningless, unless it is really musical and enhances the performance aesthetically. So the better goal would be to seek out how to develop your mind and body to be able to use a variety of tempi and note values musically.

For jazz saxophonists the gold standard for speed and musicality combined are artists such as Charlie Parker, Lester Young, Paul Desmond, Stan Getz, and others. But having studied their music, one will find that they were always extremely musical, and that even at high speeds their tone was rich and their improvisations were lyrical and dynamic. And, the true “secret” to their success is revealed in how they approached slow ballads (!).

It is often said that ballads are the surest test of a jazz musician; being able to play a ballad with intelligence and sophistication separates the average musician from the masters. Jazz ballads expose a musician’s ability to keep time at slow speeds, organize their thoughts, and demonstrate their understanding of harmony and space. Most importantly however, ballads reveal how well a musician understands what is known as the density referent.

The “density referent” in a song is the fastest unit of time that a piece of music contains or is based upon, i.e. if you are improvising over the jazz song Take The A Train at mm = 130, and the fastest subdivision of the time you can improvise in comfortably is sixteenth notes, they are your density referent. This is why it seems easier to play fast runs on a ballad, as the tempo may be so leisurely that the density referent could be as high as 32nd notes yet still be comfortably playable. This is also why young jazz saxophonists struggle with musicianship. They assume ballads are “easy” because they are slow, and have lots of space to fill up. Thus they play a density referent that crowds the music with too many notes. Likewise, when they try and play a fast number they rush and stumble, as they attempt a density referent beyond their skills.

But specifically focusing on the density referent in the practice room and in performance has many great benefits. It teaches you that musical time is not primarily a case of speed alone, rather one can move at different speeds within a given timeframe, which means we can be artistic with our time/referent choices. Thus, you are then given a better understanding of what your strengths and weaknesses are in terms of metric modulation at various tempi. You also develop a greater technical and creative control over your improvising, and are able to be more musical at higher speeds. You train you mind and body to react faster to the improvising of others, as well as play more of what you hear in your head instantaneously. Also, developing finger and mind dexterity while applying your conceptual understanding of the density referent is a transferable skill you can apply to other instruments that you double on.

To start studying density referents first go through the various jazz standards you know and find out what they are and which tempos you can handle them at. Most songs you will at least be able to play quarter notes in, so the next three densities will be eighth notes, eighth note triplets, and sixteenth notes. Catalogue the various metronome markings and referent values in your practice journal, and then begin to work on slowly increasing the tempo of the song. You’ll notice that even a small increase in tempo will increase the difficulty of the referent while hardly affecting the remaining densities. This is why you should keep track of the tempo at which you can play the density referent, not just the tempo you play the song at. If you know you can’t play sixteenth notes at certain tempi just yet, you will save yourself from playing a song too fast. Also, work on being able to play the density referent in jazz breaks or cadenzas. For faster numbers, work on being able to shift to your density referent from the note value beneath it, gradually building the ability to spend longer lengths of time at the ‘top.’

You should also gradually increase the metronome marking, noting that you can only physically play so fast. If you just can’t play sixteenth notes any faster than a certain tempo, make a note of it and then focus on making as much music as you can with the other densities remaining. A fun way to do this is to invent your own scale exercises that combine different densities (“density shifting”), i.e. create exercises that move from quarter notes to sixteenth notes with a few eighth notes and eighth note triplets in between, and so on. You should also spend some of your practice time dedicated to improvising through various density shifts. If you can’t play the density referent for more than a short burst here and there, turn this seeming “weakness” into a strength by making density-shifting part of your overall style.

By using your knowledge of density referents thusly you will be able to build something new and exciting out of what you thought was an obstacle. 


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