These studio projects with cellist Niall Brown of the Australian String Quartet, explore the interaction between instrumentalist and synthesist.
Improvisation on Bach’s Cello Suite No.2: Sarabande
This Bach material was selected primarily because of Niall’s familiarity with the piece, as I asked to improvise variations on this theme and to respond to the Clavia Nord Modular synthesizer’s harmonic textures derived from the same theme.
I first analysed the first twelve bars of the Sarabande and re-harmonized it to conform to a jazz harmonic formula (the ii-V-I progression). I used this progression to develop a 96-step (12 bars of quavers) sequence of notes generated using pattern generators that were conformed to the harmonic progression using key quantizers. The sequence steps were triggered randomly and conditionally by an inverse logic gate, so that, as the cello’s amplitude subsided in level, the synthesizer’s sound became more audible. This allowed for the development of call-and-response between cellist and synthesizer. The threshold at which the cello’s amplitude activated a sequence was varied using a foot-pedal in response to the density of the sound texture generated.
Four identical synthesizers ran in parallel whose notes were randomly generated but the output of which stepped simultaneously (clocked from the same source) through the harmonic progression. In other words, all four synthesizers followed the same harmonic form and rhythm. This provided a dense harmonic texture derived from the Sarabande ‘s first twelve bars.
I also recorded the theme and edited phrase samples from it, which I then assigned to a sampler, with the samples assigned to keys on the Korg digital piano. This allowed for the playing of discrete phrases from the Sarabande as originally played by the cellist. Given that the record chain for the performance with the cello was identical to that used in sampling it, there arises an ambiguity as to whether the phrase is being played “live”, which both the cellist and I exploited. The cellist could choose to match phrases or accompany his pre-recorded playing though counterpoint or textural exploration. Triggering samples, I was able to create new links between phrases, to deconstruct phrases by rapid re-triggering, or playing with relative dynamics. We were also able to answer each other’s phrases.
The output of the cello, the synthesizer and the sampler were each processed using a combination of delay, reverb and filters that was developed during the performance of the piece. The processing served to bring the cello and electronic instruments into the same acoustic “space”.
The performance of the piece called for the statement of the theme by the cellist, followed by the introduction of the synthesizer to lay down a harmonic bed for the cellist’s improvisations, with the addition of triggered samples to follow. The piece concluded with textures made by bowing below the bridge and processed through FX devices.
The cello is heard through heavily filtered delays stating the Sarabande theme, giving a swirling effect. Then, as the trigger threshold of the Nord Modular synthesizer is attained, the cello begins to trigger note sequences, the synthesizer sounds a dense harmonic texture related to the theme but not in harmonic rhythm with the cello’s statement of the theme. The theme breaks down as the cello improvises textures bouncing the bow on the strings, the delays multiplying the effect. Then, we hear phrases from the theme as the cello appears to accompany itself, but it is in this instance the sampler. The cello plays harmonically, below the bridge. As the level of the synthesizer drops in inverse proportion to the level of the cello, the processed cello predominates. The synthesizer and sampler respond to the cello, creating tension and release as the sounds become more and less dense and loud.
At times the delays “dry up” leaving the cello more “present”. Strong plucking of the cello strings yields exciting rhythmic patterns as the shimmering, panning delays echo these sounds. The sampled cello phrases leave the cello free to explore extreme registers with sustained bowing, tantalizing with melodic fragments. Long cello glissandi shimmer in the delays, and the delicate tones of the synthesizer bloom in the spaces. The quad modular filter envelopes open, increasing the distortion of the cello tones. In a false ending the cello is filtered to a severely diminished sound, then the cellist executes a series of rapid bow strokes with answering phrases from the synthesizer. The synthesizer drops out, leaving the cello to execute a series of delayed glissandi, the sampler re-introduces a few final phrases from the theme before the cello takes over to re-state the theme, diminishing to silence before it is completed.
Work for Cello and Moog Minimoog Voyager Synthesizer
The second piece, Work for Cello and Moog Minimoog Voyager Synthesizer was recorded in 2004. Again I worked with Niall Brown to explore a strategy for creating an interactive piece between acoustic and electronic instruments.
On this occasion, using a Korg Pitch to CV converter and Signal Processor (MS-03), I tracked the pitch and amplitude of the cello and used the resultant control voltages to modify the pitch and volume of a drone on the Voyager synthesizer. I was able to vary the portamento or glide of the pitch control; and used an attenuator to modify the envelope-follower control voltage that controlled the synthesizer volume. I used lag processors on the Korg converter and on a control voltage mixer to determine the speed at which the Voyager responded to the cello. Using a multiple module, I split the pitch control voltage so it also controlled the Voyager band-pass filter’s break frequency. The filter resonance and filter envelope amount were controlled by potentiometers, with additional control for the width of the filter band and the cut-off frequency and resonance provided by the synthesizer’s touch surface controller. The oscillator outputs were tapped and patched to the mix module’s external input, so that the mixer could be gently overdriven using its external input potentiometer. The sound of the both cello and synthesizer were processed through a reverb unit.
This piece is largely predicated on the rich overtones generated by the cello in performance.
The piece makes use of four principal approaches to sounding the cello: long slow tones where for the body of the tone the synthesizer plays in near unison; glissandi where the synthesizer follows the shorter and longer glissandi of the cello at a speed determined by the lag processors; short accented bow strokes where the synthesizer follows rapid short discrete pitches with quick glissandi, rapidly diminishing in volume; short rapid continuous bow strokes where delays in pitch tracking causes large interval leaps by the Voyager.
By using the touch surface controller, I was able to gate the band-pass filter effect rhythmically, and to create a form of glissando using the filter break-frequency parameter. This allowed for call-and-response between cellist and synthesist.
Regardless of the manner of attack adopted by the cellist, the overtones inherent in the cello’s timbre lead the pitch-follower to occasionally track the predominant partial causing the synthesizer to sound that pitch instead of the fundamental, often producing octave leaps. The tonal centre of the piece was established by the synthesized drone, to which the synthesizer returned at the end of each bow or pluck on the cello strings.
This is a mournful piece with the timbres of the cello and synthesizer sometimes blending, sometimes diverging, with the synthesizer dutifully dragging itself along behind the cello, occasionally trying to break free to a more optimistic height only to revert to its tonal centre with the irresistible pull. Tension arises between the instruments as the touch surface controller of the synthesizer is used to rhythmically gate the filtered synthesizer sound in opposition to the volume control exerted by the cello via the envelope follower. A conversation between the instruments is developed as the cello and synthesizer follow each other’s note durations and short glissandi. As the cello is played very softly at the conclusion of the piece, the pitch follower becomes less stable and the filter envelope closes.