Re-working the generated part:Before I get to orchestrating the cello solo, I decided I need to re-work the generated line. The previous line (ex.1 below) wasn't too practical, and didn't give the cellist enough leeway to work with the prepared-string to bring out the desired sounds: the whole point here is that the preparations allow for different harmonics and multiphonics to emerge, and that the tablature-style notation constrains the player's actions to limit what specific sounds emerge.
|Ex.1: cello solo v1 (notation explained below)|
To generate the part, I allowed the isorhythm (ex.2) to run for nine iterations of the pitch line ('color' seems somewhat meaningless with so many overlapping lines to this isorhythm), then copied and pasted the result a few times. Then applied the phrase-generator to this so that each copy of the 9-iterations is unique.
|Ex.2: isorhythm for cello layer of 'pitch', durations, dynamics.|
Ultimately the specification of bow-force, speed, and phrasing needed to be more intuitive, because of the complex timbre/multiphonics of the prepared-string. Previously I had used a system to generate the occurrence and lengths of hairpins/glissandi/bow-phrases (see Max patch in ex.3), which I thought would interfere with each other in a pleasing way. However, while I think this would have worked fine for a standard cello with notes and durations that the player could cleanly achieve (thus the system would create interesting textures by interfering in this), the already contingent and indeterminate cello timbre is 'choked' by the profusion of interferences. The player can't get a grip on how the instrument is responding quickly enough to coax it into coherent sounding; or at least not often enough to be a consistent part.
|Ex.3: Max patch generating the 'time' layers on top of the generated notes/durations. Console on right shows the output.|
New generative strategy:The new strategy will keep the original 'pitch' (i.e. bow position), duration and dynamics layers, and intuitively edit the 'time' layers (phrase/hairpins/glissandi) to work more naturally with the dynamics. I'll use another simple generative system to insert more flautando bowing, probably by replacing the glissandi. The glissandi were poorly thought through here, since it simply involves the bow sliding from one position to another, which tends to happen naturally, and doesn't add much to the sound. Flautando bowing (fast and generally light but can be forceful) however is quite effective because it allows the timbre to split in interesting ways, revealing further layers of harmony.
I also doubled the durations so that the part is notated more sensibly, and the conductor can beat 7 crotchets rather than 14 quavers... The new (v2) cello solo looks like this: p.1 below as ex.4. The changes are largely subtle, removing some of the more awkward phrases where a long single bow is interrupted by a f dynamic (because this necessitates a faster bow), so many of the phrases have been restarted where big dynamic shifts occur. Also, where there are explicit glissandi, these are now ties to flautando bowing so that the laterally moving bow position is accented by the rapid up/down bow changes.
|Ex.4: cello solo v2|
Cello preparations: strings III and IV at E2, strings I and II at G#3 or E3. These all theoretically allow and 'E' pitch component, but it's hard to say what other pitches will be available. The orchestration uses the magic square, so there will be a sense of E tonal centre also, though greatly distorted.
Orchestration:In the previous 'solos' (sax/perc duet, piano/guitar duet) I had kept the ensemble in the background, in this case I went the other way completely. Here, I was already worried that a single cello playing a very delicate technique might have to be completely solo, but instead I decided to try and have the full ensemble playing at all times, but at ridiculously low volumes, allowing the cello dynamic to act as a filter that lets through more or less of the ensemble.
I took the cello part, reduced it to just rhythms, and copied it into all the other parts. Then I used a forward/backward reading of the magic square and applied that to the rhythms, so my whole ensemble has a continuous pitch line that rhythmically the same as the cello part: the cello pitches of course are largely indeterminate.
The filtering process is done by switching between pitch and noise in the ensemble. For example, when the cello is f then the ensemble play pp/p notes, but when the cello is playing ppp the ensemble play a mix of air sounds and muted attacks, providing just a rhythmic shadow behind the cello. See p.1 (draft v3) in ex.5.
Listen to the rehearsal:
|Ex.5: p.1 of cello solo showing cello dynamic filtering the ensemble.|