Masters Research

Patchbay, Feedback and Transducers

Several experiments were carried out exploring various combinations of transducers, acoustic objects and DSP software. The patchbay circuit was placed in a temporary enclosure and used to control the routing of signals between these elements. Banana jacks were connected to several of the inputs and outputs of the patchbay facilitating the navigation of the interface due to their larger size and circular layout.

The placement of various objects between the input and output transducers allows the 

use the objects to filter the sound acoustically. By adjusting the positions of the transducers on the objects, different resonant modes can be excited. In this way, the transducer resembles a stethoscope or microscope, amplifying and revealing, allowing explorative listening to the internal structure and material qualities of the object.

This process becomes particularly intriguing when exploring combinations and couplings between multiple objects, producing a wide range of rattling and buzzing sounds. More specifically, bike spokes were used to create temporary structure/sculptures which could be explored by manipulating the distances, pressures and surface area between the transducers and objects. In addition to this, the constant vibration of these structures in combination with the multitude of parameters and forces involved leads to a certain unpredictability and  constant evolution in the sound.

More specifically, these experiments aimed to use the feedback tones created between transducers as raw sound material which can be dissected, processed and rearranged using SuperCollider. In addition to this, techniques for destabilising the dominant resonant tones were also explored, softening the threshold for explosion/entrainment/sympathetic resonance and allowing the system to be controlled more easily.

A combination of delays and reverb were used to reduce the speed of the feedback process. This results in a more controllable system, providing the performer more time to react to changes in the sound without losing the sensitivity provided by the acoustic interactions. Furthermore, this allows for a more detailed and contemplative listening to this iterative filtering process, as the initial sound slowly takes on the qualities of the object, creating a complex intermingling of objects and identities.

Filters were added to the input signals, allowing the performer to selectively excite and explore the various different resonances of acoustic objects. In addition to this, the amplitude of the input signal was mapped as a modulation source for the filter's cutoff and resonance. This creates more complex interactions between the electronic and acoustic sounds, destabilising the dominant feedback tones as the resonant peak is always moving. This is particularly interesting as it produces short trails of feedback as the amplitude of a sound rises and decays.

The extreme sensitivity of the system to volume changes and the precision required to bring feedback tones in slowly can be particularly problematic and usually requires the performer to make constant adjustments to the volume. Possible solutions to this problem could include the use of a volume pedal with some mapping to soften the response curve. Compression could also be used to reduce the dynamic range of the audio signal.

The placement of additional loudspeakers on the same table as the amplified objects provided a richer and more engaging experience. This is partly due to the wider frequency range of these speakers but also because interactions with the air surrounding the speakers start to influence the sound. Every subtle movement becomes amplified and significantly influences the sound. 

In this way, the amplification allows the exploration of sound as a physical phenomena, as vibrations in the surrounding space. This experience also has similarities to early explorations of acoustic instruments. In particular, the process of becoming aware of the subtle movements of the body that produce nuanced timbral fluctuations and learning to control and shape them.