Project report

soil loop

How can we make ecological activity tangible through sound? How can acoustic signals from an ecosystem - for example from the ground - be integrated into generative sound art through live audio processing? How can the interdependence of nature, humans and nature be depicted in an installative context? In the pilot project »soil loop« - developed with the support of the Department of Landscape Architecture/Environmental Planning at TH OWL and the Höxter Botanical Gardens - a computer-aided sound system was developed on the basis of acoustic input from ground microphones and presented in an immersive sound installation.

Project participants


Samuel Johnstone

Project status

Research & Implementation

Designing ecological sound systems

The aim of the project is to integrate acoustic input from an ecology through experimental miking techniques into a generative sound system through live audio processing software. The development of the project consisted of fieldwork period in spring 2024 at the Botanical Garden Höxter, followed by development phase of audio processing application; in summer 2024 the application of the system was in a sound installation »soil loop« in Höxter

Acoustic input from the environment



An innovative way to capture the acoustic input from ecological elements such as trees, plants or the ground is to focus on the vibrations transmitted through organic material such as tree trunks, root networks or the soil. Conventional microphone models such as condensers are unsuitable for this purpose, and commercially available contact microphones manufactured for amplifying acoustic instruments are too small and do not have the necessary power to generate the required acoustic input.



This project experimented with the use of geophones -
a type of ground microphone originally developed for geological monitoring - to listen to the sounds present in the ground: Insect sounds, moisture transfer through root networks, electromagnetic signals.

















GENERATIVE SOUND PROCESSING

In Pure Data, a patch for live audio processing was developed to integrate the dynamic input of geophones into a complex generative system in which the ground sounds are interwoven with an electronic soundscape. The system consists of three generative elements working simultaneously:

1. »Dry« input from two geophones, equalized and compressed

2. A multi-stage delay system for this input, automatically triggered by dynamic gates and subject to a chain of high-pass filters

3. Spectral frequency analysis of selected »frozen« moments of the microphone input, which are subjected to detuning and other transformations. In addition, parameters are integrated into this sonic system that can be manipulated by a live performer.

Immersive installation concept

For the installation, four loudspeakers were positioned at a central location in the botanical garden to create a spatial presentation of the generative soundscape. Two speakers were positioned directly next to the two geophones, with the respective output and delay systems mapped 1:1 to these two speakers to allow for direct feedback and interactivity with the ground activity at each location. The remaining two speakers were placed next to a greenhouse embedded in the garden - normally used to store materials and tools for the research activities in the Botanic Garden - where the hardware and cabling to operate the installation was presented. In this way, the interweaving of nature, human and technical elements is thematized.