The projection properties of sound sources

While working on ensemble pieces in 2016, I realised that I had been treating sound sources as points in the space, whether a physical space or the space in the listener’s mental projection. That is to say, as two-dimensional objects without depth – where depth is intended as the size that a sound can assume in the mental projection of the listener. I started wondering, instead, if the sound had a perceivable three-dimensionality which could induce me to rethink the space-sound bond.

I asked myself if the sound of an instrument could have different levels of depth, or have the capacity to create an aura of vibrations permeating the surrounding space. When I composed The Mind is the Cave (2017), I explored the idea of sonic permeability of the space with different degrees of projection. Considering the voice of a horn player as untrained (without the same volume of a professional singer), I imagined seven different states of sound arranged according to the capacity for projection, here listed from the weakest to the strongest:

1. voice stopped with the hand over the mouth or inside the horn
2. voice singing inside the open horn
3. voice singing outside the horn
4. half valve horn
5. stopped horn
6. half-stopped horn
7. open horn

These seven levels work at times alone and at others together, creating a dialogue between the performer’s body and the instrument that results in a sound source which keeps changing the intensity of its aura. Through the seven degrees of projection, the sound interacts with the surrounding space with a constantly changing response. These degrees of projection can be equated to dimensions – here intended as perceivable sizes. Once the dimension of the voice is overlaid with one of the four dimensions of the horn, the acoustic phenomenon creates inner beatings very similar to the kind of sound characteristic of certain woodwind multiphonics. It creates frequency interference, while generating an entirely new timbre with a complex depth.

In order to achieve the desired effect of sonic permeability, the piece is intended to be performed in a space with generously resonant acoustics (such as big churches or disused factories), or otherwise performed reproducing the reverberation artificially. In a natural acoustic setting, the sounds with more projection are reflected by the walls to a larger degree and fill the space with greater resonance. The reflections of the sound contribute to the dislocation of its mental projection from the location of its source, as the same sound reaches the ears from multiple directions at the same time. In fact, in highly resonant enclosed spaces, music can be mentally projected as broad and diffusely located images.

The piece presents an unusual melodic concept that places the horn out of its referential repertoire, into a forgotten territory reached only by myth. I used the neumatic notation of Gregorian chant as an abstract indication of microtonal melodic inflexions. Thus, I could find a new representation of a ritual chant, without being evocative of any particular historical (tonal or modal) genre. The result is a highly dynamic acted scene, where the spatial component played the main role, both conceptually and practically. The dramatic storyline helps the listener to interpret position and dimension of the sound source as changing constantly – located in the proximity of the performer when sung by the untrained voice, located all around the walls when projected by the rich sound of the horn. The theatrical component contributes, therefore, to enlarging the gestural space of the horn player into the “arena space” – the space where the energy of the musicians becomes one with the space occupied by the audience.

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I continued experimenting these principles in The underwater life of a bass clarinet (2021), using a prepared bass clarinet. The instrument offers a similar variety of focus/projection level in the sound. As a clarinettist, I know that multiphonics obtained through special fingering positions can have interesting effects on the physics of the instrument (I have already exploited this virtue in pieces like Neutrinos visiting and The large, the little and Pablo in the middle). Because the clarinet creates two acoustic knots at the extremities of the pipe, some particularly closed fingering combinations (opening just one or two holes) create an unusual resistance in the airflow. Sonically, it translates into sounds with pale inner beatings, soft muddy timbre, and weak projection. These sounds have a highly unstable yet wide sound spectrum that could vaguely be assimilated to pink noise: the precise pitches are not fully recognisable and form, instead, a “pitch cloud” coming from a poorly detectable sound source. In contrast, other multiphonics obtained through more open fingering combinations produce aggressive sounds that present rich and penetrating spectra.

Starting from this premise, I speculated that further disturbing the natural airflow could bring a fruitful and original exploration of extended techniques. I wanted to achieve a similar effect of the stopped horn (as described above). Simply closing the bell of the clarinet would not have much effect on the notes, because the sound-waves would travel through the open holes anyway. I needed a more flexible way to close and open the bell gradually (similarly to what the right hand of a horn player can do) but the clarinettist needs to keep both hands on the keys (and moreover, the bell would be impossible to reach because of the length of the instrument). I experimented with water, imagining that a liquid could close and open the passage when inclining the instrument at different degrees. Pouring water inside a bass clarinet bell is an entirely safe procedure because the silver bell is not damaged by water and minimal splashes reaching the wooden part would not be any more dangerous than the natural condense forming inside the bore while playing. The right amount of water would be able to fill the curve of the bell entirely, however, just enough to allow an opening if the clarinet were positioned at an angle. I started, rather empirically, experimenting with that to find fingerings that could create interesting effects of open/close notes. With pleasurable surprise, the water reacted to pressure and produced rapid modulations in the open/close action by itself. Of course, when blowing inside the instrument when all the keys are closed (so that the only available hole for the release of air is the bell), water is pushed forward to allow air bubbles to escape. The weight of water pulls the liquid back, and this process repeats in fast loops, creating unique bubbly “ring modulations” in the sound (term borrowed from electronic music). Blowing as such with all the keys closed produces too much pressure and the water gurgles aggressively. I imagined that opening only one or two holes would alleviate the pressure and allow the water to move back and forth inside the bell in a more harmonious motion. The response caused an emotional marvel: singularly opening different holes produced distinct pitches that trilled microtonally at different rates and with a distinctive bubbling noise. The speed of the trills modulates according to the width and the position of the hole along the instrument’s body. Some positions allow an acceleration in the trill, and when followed by more open fingerings which wouldn’t normally allow trills to form, the rate of the trill would slow down. Again, this process could be enhanced by inclining the instrument slightly. I could catalogue “water trills” on specific pitches, patiently creating a chart of positions, progressions of positions, and movements. Finally, I started using these as compositional elements to create the bass clarinet part of the piece.

In The Mind is the Cave, I could exploit a highly reverberative acoustics to amplify the projection of the horn. The bass clarinet would not have as much power in its sound projection to reproduce a similar effect – furthermore, I was not interested in repeating the same concept in a different piece. The narrative of The underwater life of a bass clarinet asked the solo instrument (seen as a distinguishable sound source) to sink and fade in an immersive aquatic soundscape. The only possible way to achieve that was to create an artificial acousmatic sound environment. I used synthesisers that would reproduce a uniform sound close to the bass clarinet’s timbre: a mix of sine and square waves. Filtering the synthesisers with ring modulation (imitating the bubbling noise of the “water trills”) and additive synthesis create unique effects that can at times blend with the clarinet sound, at others pull apart from it, sustain it or absorb it entirely. Once again, I invited the player to perform (ideally) from the middle of the space and surrounded by the audience; beyond the audience, multiple loudspeakers.

Working closely with Ensemble Resilience as artistic co-director, I gained valuable experience in using MIDI Polyphonic Expression controllers (e.g. Seaboard by ROLI – the name alone creates an immediate connection with the artistic intent of the piece). These controllers capture the three-dimensional movements of the musician’s hands, allowing to map the pressure applied to the key, the sliding along the key, as well as the gliding between keys (which are unified in a single keyboard-shaped soft pad) to different parameters. The musician can gradually move between different effects through faders and an X-Y pad, and create morphing combinations of timbres from the stage. Thanks to this technology, I designed deep bass sounds that can vibrate in space, and high pitch tactile sounds with undetectable location in the mental projection. A varying convolution reverb (also controlled by a fader) and randomised amplitude in the individual speakers placed around the audience contribute to give perspective to the designed sounds. Ultimately, the dramatic trajectory of the piece is characterised by deep vibrations and cringe sounds that travel through the “arena space,” progressively interfering with the clarinet “aura.”

Copyright © Gerardo Gozzi 2021