Song of the Yeast: A Microbiological Instrument is part of Joshua Penrose’s “Resonant Carboy.” The following description is from his site, which can be viewed here.
Resonant Carboy is a generative sound installation that offers high concentrations of microbiological life a unique mode of performative expression. In this installation, yeast cells (Saccharomyces cerevisiae) are given voice as they fervently reproduce during the process of fermentation. Real-time chemical reactions become the generative process powering this unfolding temporal form. Up to 1.7 trillion yeast cells will trigger a self-organizing soundscape in real-time, as they feast on the monosaccharides available in a solution of honey and water. As the yeast cells digest the sugars, they yield large quantities of carbon dioxide. The release of this gas will drive a computer software environment – an instrument – that gives voice to the microscopic chorus of chemical transfiguration as a hybrid texture of amplified natural and synthetic sound.
When approaching the installation, you see 8 half-gallon carboys, glass containers used historically in the fermentation of beer and wine. Each carboy is filled to varying degrees with golden mead-must – a solution of honey, water, and yeast. The carboys are sealed with an air-lock device, allowing the generated CO2 gas to escape. Inside each airlock, a waterproofed piezo transducer is suspended by shielded audio cable through a drilled hole in the top of the air-lock device. Each transducer is connected to a digital audio computer software application via an 8-channel digital audio hardware interface. The software listens for the “clicking” of the airlock devices. The rhythmic sequence is generated at random by the integration of the air-lock devices releasing gas. The audio software interacts with the resultant, randomly generated rhythmic sequence. This “moves” through varying states of the instrument’s processing behavior. The software instrument amplifies and digitally manipulate the sound of the trillions of present yeast cells, as well as generates single, quiet tones, creating a hybridized soundscape of both organic and synthetic. The processed sound is projected by 8 speakers, through 8 separate audio channels vectored outward from the central point of the carboys. The speakers are be placed in a circle with a slightly larger radius, thus providing a barrier to the inner circle, the sound-generating nucleus of the installation.