In 1974, Pauline Oliveros published "Environmental Dialogue" in her Sonic Meditations collection. To perform it, participants assemble in a particular location, which may be indoors or outdoors. Then, "as each person becomes aware of the field of sounds from the environment, each person individually and gradually begins to reinforce the pitch of any one of the sound sources that has attracted their attention.… 'Reinforce' means to strengthen or to sustain by merging one's own pitch with the sound source.… The result of this meditation will probably produce a resonance of the environment…."¹

Oliveros was an early mentor to David Dunn, another California-based composer and sound artist. In 1975—the year after "Environmental Dialogue" was published—Dunn composed PLACE: A Performance in Ten Parts. The two pieces share a number of similarities: both are loose text scores that allow for a wide variety of interpretations and realizations, and both are designed for a group of performers engaging with sounds around them. In particular, the seventh section of PLACE is a close cousin to "Environmental Dialogue": Dunn asks a solo vocalist to "sustain pitches in response to pitches heard in the environment. An attempt should be made to trigger resonances in the environment and reinforce these through the selection of pitches."²

Upon closer analysis, subtle yet important distinctions between the two pieces become apparent. While both composers are interested in the concept of resonance, their usages of the term “resonance” in the two pieces seem to diverge. To Oliveros, a “resonance of the environment” involves a subtle echoing of the pitches or timbres present at the performance location. The result is meditative, inward, and ultimately one-way: a performer receives the sounds of the environment and then reacts with a contribution of sound. Dunn’s PLACE, by contrast, interprets “resonance” in terms of acoustic phenomena: reverberations, reflections, and perhaps even a sonic response from non-human species at the performance site. The text directions specifically require the performer to take into account the resonances that result from his/her voice, making active choices about future sound-making based on the sonic effects of these resonances.

Dunn is interested in directing our attention towards the continuing relationship between the performers’ sounds and the environment, rather than merely a one-way echo of the environment. An effective feedback loop is created: the performance site alters the sounds of the performers, and thus causes them to alter the sounds they make in response. In this sense, Dunn's piece stands as a more meaningful example of “dialogue” than Oliveros's meditation. In PLACE, there exists a real back-and-forth conversation, with each side informing the other. By calling on the performers to "trigger resonances," Dunn sets up conditions for the performance location’s acoustic environment to talk back.

This core idea—a performance that manages to initiate a two-way dialogue between music and environment—served as a recurring theme across many years of Dunn’s compositional output. While PLACE focused primarily on humans and the possibilities of their interactions with the environment, in 1976, Dunn and collaborator Ric Cupples created Mimus Polyglottos, which more explicitly attempted to spark an interspecies dialogue. In Mimus Polyglottos, a fixed tape of analog-synth electronic sounds mimicked both the frequency range and morphology of the song of the Northern mockingbird. Dunn and Cupples then broadcast this tape in the presence of a mockingbird and recorded the results. In a later interview, Dunn recalled: "The idea was to focus on that property of sound-making that would emerge from the interaction that was occurring in the environment…. We played it to the bird and instantly the bird started to imitate and match pitches—there appeared to be some form of improvisation around this foreign sound source."³ The resulting field recording, which features both birdsong and synthesizer, is another type of feedback loop: a conceptual dialogue where the mockingbird's singing informed the original construction and content of the electronic sounds, and then the electronic sounds went on to affect the song-production of an actual bird.

For several decades, Dunn continued to expand these ideas, envisioning large outdoor site-specific installations that would generate—in real time—the kinds of sonic interactions heard in Mimus Polyglottos. His earliest realizations of this concept, labeled Sonic Mirror (1984–1987), used a custom-designed "portable computer system for environmental interaction" to record, process, and play back natural sounds. Dunn, however, was ultimately disappointed in the results of the Sonic Mirror project and shelved the concept for nearly fifteen years.

By the early 2000s, portable computer technology had advanced to the point where it made sense to revisit the concept. Dunn created a series of pieces called Autonomous Systems (2003–2005), wherein an outdoor microphone records live natural sounds and sends them into a computer. Custom software then analyzes snippets of that sound, processing them and playing them back into the environment. Dunn describes the process: "The installation uses a small computer system programmed to autonomously process acoustical information from the environment….The resulting soundscape is a combination of self-organizing autonomous machine-based structures and processed samples from the external world that interact and influence each other."⁴ In other words, once the system is activated, it runs on its own, capturing sounds from the environment and responding with sounds that then become a part of the environment.

Thirty years after he composed 1975's PLACE—an invitation to listen more closely to the conversation between human voices and the resonances of the natural world—Dunn continued to focus on interactions with the sounds of the environment. His creative path had led him from text instructions for human musicians to collaboration with non-human musicians and ultimately to the "machine-based structures" of computers. Rather than generating an original sonic world ex nihilo and bringing it to life, Dunn offers instead a subtle reimagining of an existing sonic world, setting in motion a framework where the work’s content emerges naturally from a multiplicity of site-specific inputs. In Autonomous Systems, Dunn finally manages to create a new kind of conversation, perhaps the most elegant feedback loop of his oeuvre: a running dialogue between the sounding world and itself.