Cello solo v1The cello solo will use my prepared cello: not a million miles from a prepared piano as mentioned in previous blog post. The preparations make pitch quite indeterminate, so rather than generate a stream of pitches (like for the guitar/piano) what I wanted to generate was essentially a tablature score for the cellist to create a stream of actions that would limit the indeterminate pitches in different ways to create loose patterns. Tablature notation differs from standard notation be being more about telling the player what do (what actions to carry out, where to put fingers etc.) rather than what sound/note to make. It can be especially useful in situations where the specific pitch result is indeterminate so instead the notation deals with timing, positions etc. See Aaron Cassidy's scores and writings on this as a good example. Below is a page of his solo for any bowed-string instrument, with staves for: (top) fingerings and bowing on the four strings; (middle) finger-width spacing on a scale of 1/tight to 5/wide; and (bottom) left-hand position on the fingerboard, written according to string conventions for playing scales (i.e. 1st position, 2nd position etc).
|ex.1: The Crutch of Memory, tablature score for bowed-string instrument by Aaron Cassidy.|
My cello preparations involve plastic or metal objects (currently a triangle-shaped wedge) placed between two strings: see ex.2 video below where I talk through the preparation use. These objects act partially like a finger on the string in something between a harmonic pressure and a fingered pressure. So the position on the string can be heard as a pitch (or pitch colour at least), but the harmonic-like pressure also means that the main timbre component is like a harmonic rather than a stopped note. Further complicating this, the preparation itself channels vibrations from one string to another, interfering with it, and the weight of the preparation alters the ratio of string mass to length, which changes it's harmonic structure into an bell-like 'inharmonic' timbre. When this is bowed, the sound splits into different harmonics and multiphonics in a way that is specifically indeterminate but can be locally navigated.
|ex.2: cello preparation example.|
Initially I thought that Xenakis' 3D cubes would be the best way forward, because it's essentially a permutation system that would allow me to create a constantly changing pattern based on a number of elements. So I designed a basic cube (see ex.3-left) that used an inner set of durations (to create a rhythmic pattern) and an outer layer of dynamics; though it should be noted that the cello preparations make the string very sensitive, and using different bow force/speed can give very different pitches (harmonics), so really the dynamics here are just a shorthand for 'force', not necessarily loudness. Since different dynamics can give different pitches, I essentially now had a way to generate a stream of notes.