These research notes consider sound and listening as providing a conceptual framework for Re-Imagined Radio. This framework also informs the research and creative practices undertaken by Radio Nouspace and the DHSI Sounds and Digital Humanities course. These notes are rough maps, blueprints for further explorations.
There are several reasons for a focus on sound . . .
Sound > definition
We might define sound as our physical subjective experience of acoustic energy—a sequence of pressure variations—that travel through some medium (air, gas, water) to our ears.
Sound originates from some source, usually a vibrating object. An object is set to vibrating by being struck, or rubbed, or otherwise impacted by another object. For example, one strikes a drum with a stick, plucks a guitar string with a finger, or blows across a reed in a wind instrument.
As the vibrating object pushes pushes against the molecules in the surrounding medium, a momentary region of high density called "compression" is created. As the vibrating object pulls back, away from the surrounding medium, a momentary vacuum, called a "rarefaction" is created. As the surrounding medium is pushed and pulled, pulses of acoustic energy radiate away from the vibrating sound source. It is not the actual compressions or rarefactions that radiate away from the sound source, but rather their effect on the surrounding medium.
The acoustic energy created by the sound source radiates spherically from the source at a speed of 1,128 feet (two tenths of a mile) per second, 13 miles per minute, 770 miles per hour. As the acoustic energy travels further from its source it must push against a larger and larger amount of the surrounding medium (air). This expends energy, the sound pressure and thus the sound level decreases. So, the closer you are to the sound source, the louder the sound; the farther away, the fainter the sound.
Acoustic energy travels through a medium (like air) in the form of wave, which visualized from the
side introduces see some important sound waves concepts.
Amplitude = the strength of compression and rarefaction; maximum extent of the vibration; the amount of energy (voltage) present in the signal. The higher the amplitude, the louder the sound.
Cycle = one period of compression + one period of rarefaction; highest to lowest; height of sound wave. The higher the cycle, the higher the pitch of the sound.
Frequency = the number of cycles in one second; measured in Hertz (Hz); 440 Hz=440 cycles/second
When sound waves arrive at the human ear they trigger sensory stimuli in the brain where they are experienced as being "heard." In order to be heard by the human ear, sounds generally have to be in a frequency range of 20-20,000Hz. Remember: Hz is a unit of frequency defined as the number of complete cycles per second. Human hearing is within the range of 20-20,000 complete cycles of a sound vibration per second
Communications theorist Marshall McLuhan says sound provided the first frame of reference through which humankind attempted to create and communicate a world view. McLuhan and his son and collaborator, Eric, describe two spaces, acoustic and visual, in which humankind has contextualized itself with different results. "Acoustic space . . . is spherical, discontinuous, non-homogeneous, resonant, and dynamic. Visual space is structured as static, abstract figure minus a ground; acoustic space is a flux in which figure and ground rub against and transform each other" (McLuhan and McLuhan 1988, 33). 
McLuhan says visual space, "is . . . a space [fostered] by the eyes when separated or abstracted from all other senses." Acoustic space "is the natural space of nature-in-the-raw . . . [facilitated in] the mind's eye" (McLuhan 2004, 71).
A focus on visual sense promotes several significant outcomes: It objectifies our relation with the world, promotes linearity, defines presence, and organizes ideas in binaries (McLuhan 2004, 69, 70).
On the other hand, the aural sense envisions no space between subject and object, "experiences. . .timelessness," understands truth through direct contact and interconnection with others, and organizes thought as "both-and" rather than this or that (McLuhan 2004, 70, 71).
Acoustic space is a world awash in sounds. With aural information emerging from all directions, and with no opportunity to shut off or organize the constant stream of sound, pre-writing humankind, the only to experience acoustic space, according to McLuhan, perceived its world as both surrounding and inclusive, a permeable extension of itself, and they of it (Levinson 1999, 6).
McLuhan argues that only one time in human history, Ancient Greece, was bicultural, with complimentary investments in acoustic and visual (alphabetic) spaces. With all senses translated equally into each other, says McLuhan, humankind is balanced, consistently distributed (McLuhan 2004, 69).
Since the collapse of the oral tradition in Ancient Greece, the Western world has lived in a container, says McLuhan, with all things arranged in a linear geometric order leading to a distant vanishing point (McLuhan 2004, 68). The intensity of this visual orientation leads to suppression of hearing and other sensory connections with the surrounding world, as well as a chronological orientation of past, present, and future as distinct frames of reference along a linear path. Prior to the ascendency of visual, life was like being inside a sphere. Boundless, directionless, devoid of any horizon, no straight lines, objects resonated with each other. The order was circular. The world was multicentered and reverberating (McLuhan 2004, 68). "Visual space structure is an artifact of Western civilization created by Greek phonetic literacy" (McLuhan 2004, 71).
Trouble occurs, says McLuhan, when one sense receives more energy than others. For Western culture, this is the case with the visual. "By neglecting ear culture, which is too diffuse for the categorical hierarchies of the left side of the brain, he has locked himself into a position where only linear conceptualization is acceptable" (McLuhan 2004, 69).
So, we realize sound as a primary sensory input, capable of creating deep, rich mental images and emotional responses more powerful and encompassing than visual space with its more precise and limited fixed point of view. Even after the ascendency of visual space, acoustic space is characterized by Edmund Carpenter as foregrounding the verbal, musical, and poetic traces and fragments of oral culture (Carpenter 1970).
Building on this idea, Don Ihde says, "In the most general terms, auditory imagination as a whole displays the same generic possibilities as the full imaginative mode of experience. Within the active imaginative mode of experience lies the full range from sedimented memories to wildest fantasy. . . . Within the range of the imaginative, auditory imagination may accompany other dimensional presentifications (Ihde 1976, 61-64).
According to Bruce R. Smith, sound is pervasive. Most humans, he says, "live immersed in a world of sound . . . sound is at once the most forceful stimulus that human beings experience, and the most evanescent" (Smith 2013, 127, 128). Most academic disciplines are vision-based, he continues, not only in the materials they study, but in the theoretical models they deploy to interpret those materials. Sound, says Smith, as an object of study, has been neglected. Unless recorded, many historic sounds are no longer available for study, or are difficult to study. This is unfortunate, he concludes, as knowing the world through sound is fundamentally different from knowing the world through vision (Smith 2013, 129). Steven Feld concurs, noting "the primacy of sound as a modality of knowing and being in the world" (Feld 2003, 226). Sound, says R. Murray Schafer, provides a place in which embodied social and cultural traces can be carried, often without the awareness of their bearers (Schafer 1977). Marshall McLuhan connects sound with a "subliminal echo chamber" capable (through listening/hearing) of evoking memories/associations long forgotten or ignored (McLuhan 1964, 264). Tim Crook says sound very effectively prompts life from little details "seen" in the mind's eye (Crook 1999, 8). Such glimpses promote imagination, interaction, even immersion.
Sound puts one in the environment/the world . . . Sound provides layering, ambience, atmosphere . . . Sound puts the listener in the action
Sound, hearing, and listening are real and concrete participatory practices.
Sound seizes / stimulates the imagination, creates a visual world in the listener's mind, promotes reflective inquiry, provides us with power to change ourselves.
For McLuhan, "the 'content' of any medium is always another medium. The content of writing is speech, just as the written word is the content of print, and print is the content of the telegraph. If it is asked, 'What is the content of speech?,' it is necessary to say, 'It is an actual process of thought, which is in itself nonverbal'" (McLuhan 1964, 23-24). Speech, as the expression of thoughts and feelings by articulate sounds, incorporates abstract thought and extends its ability to explain and/or characterize human agency and situation.
Speech tamed the acoustic wilderness by translating abstract thought into communicable ideas. Storytellers produced explanations for the sounds in acoustic space and wove them into larger narratives that helped explain the presence and purpose of humankind. Orality provided a means to preserve and share cultural histories and memories, a human tendency documented by Joseph Campbell who investigated the reenactment of myths as ritualistic participatory drama, often involving narrative, music, and/or other sound sources, by cultures around the world (Campbell 1949).
Alphabets and writing (and printing and reading), in turn, by visualizing its sounds, incorporate and preserve speech while extending its reach beyond the transmission range of the human voice. With the advent of writing, during the height of ancient Greece, speech was visualized, replacing the speaker's voice with text. Printing and distribution of texts, encouraged humankind to see and read (literally and figuratively) the world as a series of discrete pieces, letters and words strung like beads on a linear continuum running from the past, through the present, toward the future. As this emphasis on visualization continued with film, television, and the World Wide Web, the visual was elevated as the primary sensory input. Sound was relegated to a secondary, augmenting role to the visual. 
However, even as new visual media replaced / extended the older orality, they incorporated its content: spoken narrative, storytelling, drama, and literature, and various literary practices associated with their creation and consumption. Thus, speech (as sound), with its origins in abstract thought and presentation, is the oldest medium and the most prevalent form of human communication. It claims a presence in most all media that follow (Levinson 1999, 42; Levinson 1981). As James O'Donnell notes, "the manuscript was first conceived to be no more than a prompt-script for the spoken word, a place to look to find out what to say . . . to produce the audible word" (O'Donnell 1988, 54).
McLuhan hoped that electric media (primarily television) would reverse the ascendency of the visual and retransition humankind into acoustic space. McLuhan argued that electric technologies extended the human nervous system into a global embrace, abolished time and space, and imploded divisions between formally diverse peoples and cultural issues. The world, he said, had shrunk to village size. He saw possibilities for far-flung citizens, through electric interdependence, to live once again, as in earlier oral contexts, under the conditions of a global village (McLuhan 1962, 31).
Within this global village, issues and peoples are no longer separate, or unrelated. Instead, people are part of each others lives (McLuhan 1964, 20). In the global village, people share information simultaneously "a brand-new world of allatonceness [all-at-once-ness; everything happens at the same time] . . . a global village . . . a simultaneous happening. We have begun again to structure the primordial feeling, the tribal emotions from which a few centuries of literacy divorced us" (McLuhan 1967, 63).
 Marshall and Eric McLuhan expanded the terms "figure" and "ground," both coined by psychologist and phenomenologist Edgar Rubin in 1915, to explore visual perception. By figure, the McLuhans mean any object rising from or receding into ground. Ground is surface, configurational and comprised of all available figures (McLuhan and McLuhan 1988, 5). As Thomas MacFarlane explains, ground is subliminal, always beyond perception except through analysis of emerging and receding figures (MacFarlane 2013, 62). We may connect ground and figure with McLuhan's idea of acoustic space. Acoustic space is ground, the surface from which emerge figures (sounds) and into which they recede.
MacFarlane provides an interesting example in his book, The Beatles and McLuhan: Understanding the Electric Age. MacFarlane discusses how The Beatles, four young men from England then and still reigning as the world's most famous and influential rock music group, used multi-track recording technologies from 1964-1970 to explore McLuhan's predicted shift from visual modes of perception to a way of knowing based increasingly on sound, a shift to a world where immersion in a global community trumps the fixed individual viewpoint. They stopped touring, concentrating their time and effort instead in the studio where they produced increasingly complex narrative recordings. The Beatles, the group, as a form of ground [MacFarlane 2013, 109), engaged with recorded sound to create a "technological fable (myth)" (MacFarlane 2013, 104) that required active participation from all band members (figures) as well as audience to achieve its creation and consumption.
 Marshall McLuhan argued that alphabets and writing preserved and extended the aural nature of speech. But, Plato argues in Phaedrus, the first critique of writing, written circa 360 B.C.E., that the absence of the rhetor/writer means the text cannot be questioned and is therefore suspect. Plato's work might be considered a landmark in the debate over orality vs. writing. Prior to the age of Plato, speech was the repository of memory. The ear dominated the mind's eye. Writing removed the sound source, placed the source of credibility with seeing. For a long time ancient Greece was bicultural with orality and writing in uneasy coexistence. Orality slowly wound down, until it was replaced by typography and book publication.
Campbell, Joseph. The Hero with a Thousand Faces. Bollingen Foundation, 1949.
Carpenter, E. They Became What They Beheld. Outerbridge & Dienstfrey, 1970.
Crook, Tim. Radio Drama Theory and Practice. Routledge, 1999.
Feld, Steven. "A Rainforest Acoustemology." The Auditory Culture Reader, edited by
Michael Bull and Les Back, Berg, 2003, pp: 223-239.
Accessible at http://pzacad.pitzer.edu/~mma/teaching/MS115/readings/Feld.pdf
Ihde, Don. "Auditory Imagination." The Auditory Culture Reader, edited by Michael Bull
and Les Back, Berg, 2003, pp. 61-66.
First published Ihde, Don. Listening and Voice: A Phenomenology of Sound. Ohio University Press, 1976, pp. 133-139.
Levinson, Paul. Digital McLuhan: A Guide to the Information Millennium. Routledge, 1999.
Levinson, Paul. "Media Evolution and the Primacy of Speech." ERIC #ED 235510, 1981.
MacFarlane, Thomas. The Beatles and McLuhan: Understanding the Electric Age. The Scarecrow Press, 2013.
McLuhan, Marshall. "Visual and Acoustic Space." Audio Culture, edited by Christoph Cox and Daniel Warner, Continuum Press, 2004, pp. 67-72.
McLuhan, Marshall and Eric McLuhan. Laws of Media: The New Science. University of Toronto Press, 1988.
McLuhan, Marshall with Quentin Fiore and Jerome Agel. The Medium Is the Message: An Inventory of Effects. Bantam Books, 1967.
McLuhan, Marshall. Understanding Media: The Extensions of Man. McGraw Hill, 1964.
McLuhan, Marshall. The Gutenberg Galaxy: The Making of Typographic Man. University of Toronto Press, 1962.
O'Donnell, James J. Avatars of the Word: From Papyrus to Cyberspace. Harvard University Press, 1988.
Schafer, R. Murray. The Tuning of the World: A Pioneering Exploration Into the Past History and Present State of the Most Neglected Aspect of Our Environment: The Soundscape. McClelland and Stewart, 1977.
Smith, Bruce R. "Tuning into London c. 1600." The Auditory Culture Reader, edited by Michael Bull and Les Back, Berg, 2003, pp. 127-136.
Hearing Is Not Listening
In addition to the five most familiar human senses—hearing, sight, taste, touch, and vision—we might also consider our ability to sense balance/gravity, body awareness, pain, smell, and temperature. Of these nine senses, hearing is the first to become functional.
Hearing is the ability to perceive sound and the information it carries by detecting changing vibrations in a surrounding medium, through the ears. Human hearing organs begin developing within three weeks of conception. At around twenty weeks gestational age, the ears of an unborn human are functional.
At first, unborn humans hear only low noises, the blood whoosing, the stomach gurgling, the heart beating. As development continues, higher pitched sounds are perceptible as well.
Walter Murch, Oscar award winning film editor and sound designer, describes the hearing experiences of unborn humans quite poetically. "Hearing is the first of our senses to be switched on, four-and-a-half months after we are conceived. And for the rest of our time in the womb—another four-and-a-half months—we are pickled in a rich brine of sound that permeates and nourishes our developing consciousness: the intimate and varied pulses of our mother's heart and breath; her song and voice; the low rumbling and sudden flights of her intestinal trumpeting; the sudden, mysterious, alluring or frightening fragments of the outside world—all of these swirl ceaselessly around the womb-bound child, with no competition from dormant Sight, Smell, Taste or Touch. . .. So although our mature consciousness may be betrothed to sight, it was suckled by sound, and if we are looking for the source of sound's ability—in all its forms—to move us more deeply than the other senses and occasionally give us a mysterious feeling of connectedness to the universe, this primal intimacy is a good place to start" (Murch 2005).
Listen to "Womb Tone," recorded by Murch's wife, Muriel, a former midwife and now working in radio.
Murch says newborns rely predominately on hearing before their visual acuity has stabilized. So, from early on, sound, and hearing, is an integral part of how humans experience their surrounding worlds.
Hearing, experiencing our surroundings, may be more automatic, effortless, a background activity while we focus on other cognitive or emotional tasks. According to Martin Heidegger, "Listening to . . . is Dasein's (everyday human existence; human being) existential way of being-open as being-with for others. Indeed, hearing constitutes the primary and authentic way in which Dasein is open for its ownmost potentiality-for-Being—as in hearing the voice of the friend whom every Dasein carries with it. Dasein hears because it understands" (Heidegger 1962, 206).
Unpacking Heidegger's statement suggests discourse (speaking, the way of speaking), is a way (the aim) of communicating Dasein's state of mind, sense of being-in-the-world, disclosing existence. Discourse is the articulation, the communication, the making known. These are not elements of language, but rather existential characteristics rooted in Dasein's being. From them, language develops. Hearing (listening to another speaking) is essential to discourse. Hearing is the primary way in which Dasein is open to being-in-the-world, to understanding.
On hearing, Heidegger elaborates, saying, "What we 'first' hear is never noises or complexes of sounds, but the creaking wagons, the motor-cycle. We hear the column on the march, the north wind, the woodpecker tapping, the fire crackling. It requires a very artificial and complicated frame of mind to 'hear' a 'pure' noise. The fact that motor-cycles and wagons are what we proximally hear is the phenomenal evidence that in every case Dasein, as Being-in-the-world, already dwells in the midst of what is ready-to-hand within-the-world. It certainly does not dwell proximally in the midst of 'sensations'; nor would it first have to give shape to the swirl of sensations to provide the springboard from which the subject leaps off and finally arrives at a 'world.' Dasein, as essentially understanding, is proximally alongside what is understood" (Heidegger 1962, 207).
Again, to unpack Heidegger's thinking, what we first hear is never complex noises, but rather the sound object itself. The mind experiences objects directly, not representations of objects. One does not first hear a noise and infer that it is motorcycle, but rather hears the motorcycle directly. Hearing requires unusual and complex thinking to decode noise first heard into an understanding / association of the thing that is providing the noise/sound we are hearing. We are hearing life. We are hearing things as themselves. We are proximally alongside what we hear and understand.
NOTE: See also Research > Radio Drama for information of listening to radio drama.
Different from hearing, perceiving sound and the information it carries, listening is the active processing of auditory stimuli. Listening is a carefully considered and purposefully conducted activity, involving conscious effort and attention.
French critic and composer Michel Chion, in his discussion of aural relationships to sound in
cinema, suggests we listen for several reasons:
To obtain information about the sound source
To appreciate the sound itself
To learn what is communicated by the sound (Chion 1994).
Jay Allison, one of National Public Radio's most honored producers, is quite poetic regarding listening when he says, "The earliest stories were told out loud. When we tell stories on the radio, we tap into a primitive and powerful human tradition, even an imperative, to speak and be heard, to compel listening. . . . Radio is, after all, a performance art, its stories told in time, complete with scene, character, and conflict, needing rhythm, pacing, climax to hold interest" (Allison 2010, 184, 186-187).
Tim Crook categorizes listening experiences as either elliptical or parabolic depending on physical position of the listener, the imaginative spectacle, and the acoustic space. In a parabolic listening experience, the listener is engaged in some way with the outside world. Sounds from this world compete with those presented for listening. The listener may be active, engaged with other activities at the time of listening. As a result, priority is not given to the listening experience. With elliptical listening, the acoustic space is designed to maximize appreciation of the sound quality. The listener is static in this controlled environment; the outside world is ignored. She is fully engaged at the highest level with the imaginative spectacle being presented for listening. Gary Ferrington likens such purposeful listening to "theater of the mind," where every individual listener is her own dramaturge (Ferrington 1994). The result can be quite powerful, according to Crook, who says sound prompts life from little details "seen" in the listeners' mind's eye very effectively (Crook 1999, 65-66). "It is auditory in the physical dimension but equally powerful as a visual force in the psychological dimension" (Crook 1999, 8).
Listening Opens a Portal
Said another way, sound promotes visualization of something that is only heard. Once we link a sound to an image, the sound is that thing signified by the image. Listening (carefully and purposefully) to such sounds might, according to Alan Hall, offer "a [sound] portal through which a deeper, often inarticulate, consciousness can be glimpsed. . . . The intention is to find deeper and wider resonances within—and without—the listener" (Hall 2010, 99, 104). Susan Douglas says this glimpse is of the preliterate world where orality and storytelling and imagination held great power for cognition and emotion (Douglas 1999, 29). Speaking specifically of radio listening, Douglas calls it "magic." The magic, she says, is in the act of listening, "in relying on and trusting your ears alone to produce ideas and emotions. The magic comes from entering a world of sound, and from using that sound to make your own vision, your own dream, your own world" (Douglas 1999, 28).
Modes, Kinds, Types of Listening
One might, preliminarily, imagine three modes of listening: physical, semantic, and emotional. Physical listening can be connected to the intensity of the sound which is the focus of the listening experience. Semantic listening considers the meaning of what is heard. Emotional listening considers the impact or stimulus of the speaker's voice resonating in the body of the listener. Thus, active listening evokes social-political participation. With no opportunity to see the speaker, we are forced to listen. The radiophonic voice is a trace, immaterial, yet powerful enough to determine some features of the speaking body: tone, disposition, age, origin, gender, education, etc.
Douglas outlines three kinds of radio listening: informational, dimensional, and associational. Informational listening involves a search for dates, names, locations—information—there is little effort to imagine much. Dimensional listening, on the other hand, is all about imagining people and locations and activities. This is hard work, but "gratifying because it is our own invention." Associational listening creates links and connections between our memories, personal lives, and popular culture (Douglas 1999, 34-35).
Connecting to these ideas, Michael Bull and Les Back suggest by considering sound through listening we open new ways of thinking about and appreciating the social experience, memory, time, and place—the auditory culture—of sound (Bull and Back 2003, 12). They advocate "deep listening" or "agile listening," both of which involve "attuning our ears to listen again to the multiple layers of meaning potentially embedded in the same sound." Deep listening, they say, also involves "practices of dialogue and procedures for investigation, transposition and interpretation" (Bull and Back 2003, 3-4).
The term deep listening was proposed by Pauline Oliveros in the 1970s to describe a philosophy of "listening in every possible way to everything possible" (Oliveros 1995).
Bull and Back argue several outcomes from deep listening:
"Sound makes us rethink our social experience, its meaning, nature, and significance.
Sound makes us rethink our relation to community.
Sound makes us rethink our relation to others, ourselves, and the spaces and places we inhabit.
Sound makes us rethink our relationship to power" (Bull and Back 2003, 3-4).
In short, sound provides a place in which embodied social and cultural traces can be carried, often without the awareness of their bearers. Therefore, it is good to choose to actively and deeply listen to the sounds of the world in which we live. By moving "into sound" we open new ways of thinking about and appreciating the social experience, memory, time, and place—the auditory culture—of sound (Bull and Back 2003, 16).
In addition to deep listening, we might also consider acousmatic, ambient, or profound listening. Sound artist Francisco López uses the term "profound listening" to denote close, attentive listening, listening without constraints in order to explore and affirm all the information inside any sound (López 2004, 82-83).
Ambient listening, as defined by Brian Eno, principal innovator of ambient music, is an accompaniment to life activities, often a background or secondary activity. Primarily, the sound source is (ambient) music, which he defines as "new music" whereby "compositional attention" to technological production is key (Eno 2004, 95). The goal of ambient music is to produce music that offers "an atmosphere, or a surrounding influence: a tint" (Eno 2004, 96). Since the music is designed to be predictable, attentive listening is not required for best experience. The desired outcome is to have the music become part of the background against which people live their lives.
Pierre Schaeffer, electroacoustic musician-theoretician and pioneer of musique concrète, defines acousmatic as "a noise that one hears without seeing what causes it" (Schaeffer 2004, 77). With acousmatic listening we no longer are concerned with the Cartesian split between objective and subjective reality. Instead, it is the listening itself, as a process, that becomes the phenomenon to be studied. The question "What am I hearing?" asks one to describe the perception itself, not simply the external references. The acousmatic situation generally precludes any relation with what is visible, touchable, measurable (Schaeffer 2004, 78).
The study of acousmatics is important for several reasons, according to Schaeffer. Acousmatics, he says, emphasizes the "subjectivities" involved in listening, focuses attention on the "sonorous object," what we are hearing, rather than the sound source, and strips sound back to a state beyond interpretation (Schaeffer 2004, 78, 79, 81). When listening to sounds which are hidden from view we take interest in them for themselves. We can gain knowledge of these sounds, we can analyze and describe them, and, we hope, we can transmit this knowledge.
What does listening have to do with radio? Susan Douglas suggests a return "into the realms of preliteracy, into orality, to a mode of communications reliant on storytelling, listening, and group memory" (Douglas 1999, 29).
Radio is taken as part of the fabric of daily life. We hear voices on the radio as the people they are. We hear them speaking as persons. Radio allows us to be / facilitates our being interpersonal. Radio promotes the ability to be sociable, at ease with others and self, as if we are with friends.
On form of listening is via recordings. Jacques Derrida, talking about recordings of voice, says, "If one holds the voice to be an auto-effective medium (a medium that presents itself as being auto-effective, even if it isn't), an element of absolute presence, then the fact of being able to keep the voice of someone who is dead or radically absent, of being able to record, I mean reproduce and transmit, the voice of the dead or absent-living, is an unheard of possibility, unique and without precedent. Whatever comes to us through the voice thus reproduced in its originary production is marked by a seal of authenticity and of presence that no image could ever equal. The power of television is vocal, at least as much as radio. The artificial and synthetic recomposition of a voice is much less suspect than is that of an image. . . . [A] voice still arouses suspicion much less easily, much less spontaneously, than an image. This is related to the value of real presence imparted by the spectrality of a reproduced voice—to a degree and according to a structure that visual virtuality will never reach. It is because phenomenal auto-affection refers us to a living proximity, to the emitting productive source, something the camera that captures an images does not do. The recording of the voice reproduces a production. The vocal "image" is the image of a living production and not of an object as spectacle. In this sense it is not even an image any longer, but the re-production of the thing itself, of production itself. I am always overwhelmed when I hear the voice of someone who is dead, as I am not when I see an image or a photograph of the dead person. . . . I can also be touched, presently, by the recorded speech of someone who is dead. I can, here and now, be affected by a voice from beyond the grave. . . . A miracle of technology" (Derrida 2001, 70-72).
As to why this is so, Derrida explains, "[Recording] is reproduction as re-production, of life itself, and the production is archived as the source, not as an image. . . . Life itself can be archived and spectralized in its self-affection, because one knows that when someone speaks he affects himself, whereas when someone presents himself to be seen he does not necessarily see himself. In the voice, self-affection itself is (supposedly) recorded and communicated. And this supposition forms the essential thread of our listening" (Derrida 2001, 71).
There is much to unpack in both these statements by Derrida, but we might translate the theme thus: What is it to hear the voices of the dead? We do not hear them as spectral voices. Through recordings, past events and people come to life, to presence, to the present.
Extrapolating Heidegger, Derrida says what matters is the hearing of the voice for "this hearing could not open Dasein for 'its ownmost potentiality-for-Being,' if hearing were not first the hearing of this voice, the exemplary metonymy of the friend that each Dasein bears close itself" (Derrida 1993, 164).
When we listen to the radio the past reenters the present and comes to life once again.
Recording(s) of sound(s) are not, however, sonorous objects, except in our listening. Rather, they are traces of the original. Repeated/refined listening(s) makes us aware of our listening variations and we better understand our own subjectivity, our own relation(s) to the sonorous object. Variations in recordings do not represent imperfections with the recording signal, but rather new aspects of that on which our attention is focused. Thus, with acousmatic listening, the sonorous object is a signifier for the many meanings it might convey.
Sound is, thus, relative to our listening experience. This point is considered by Brian Kane, in his scholarly study of Schaeffer's theory of acousmatics, as he argues for acousmatic listening to take a central role in sound and music aesthetics, sound studies, literature, and philosophy from a number of methodological perspectives—historical, cultural, philosophical, and musical (Kane 2014). 
Allison, Jay. "Afterword." Reality Radio: Telling True Stories in Sound, edited by John Biewen and Alexa Dilworth, University of North Carolina Press, 2010, pp. 183-196.
Website for book
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Chion, Michel. Audio-Vision Sound on Screen. Translated and edited by Claudia Gorbman, Columbia University Press, 1994.
Crook, Tim. Radio Drama Theory and Practice. Routledge, 1999.
Derrida, Jacques. "Above all, no journalists!" Religion and Media, edited by Hent de Vries and Samuel Weber, Stanford University Press, 2001, pp. 56-93.
Derrida, Jacques. "Heidegger's Ear: Philopolemology." Reading Heidegger, edited by John Sallis, University of Indiana Press, 1993, pp. 163-220.
Douglas, Susan. Listening In: Radio and the American Imagination, from Amos 'n' Andy and Edward R. Murrow to Wolfman Jack and Howard Stern, Times Books, 1999.
Eno, Brian. "Ambient Music." Audio Culture: Readings in Modern Music, edited by Christoph Cox and Daniel Warner, Continuum Press, 2004, pp. 94-97.
Ferrington, Gary. Audio Design: Creating Multi-Sensory Images For The Mind. Journal of Visual Literary, vol. 14, no. 1, Spring 1994, pp. 61-67.
Hall, Alan. "Cigarettes and Dance Steps." Reality Radio: Telling True Stories in Sound, edited by John Biewen and Alexa Dilworth. University of North Carolina Press, 2010, pp. 96-107.
Heidegger, Martin. Being and Time. Translated by John Macquarrie and Edward Robinson, Harper & Row, 1962.
Kane, Brian. Sound Unseen: Acousmatic Sound. Oxford University Press, 2016.
López, F. "Profound Listening and Environmental Sound Matter." Audio Culture: Readings in Modern Music, edited by Christoph Cox and Daniel Warner, Continuum, 2004, pp. 82-83.
Murch, Walter. "Womb Tone." Transom Review, vol. 5, no. 1, April 1, 2005.
Murray, Annie and Jared Wiercinski. "A Design Methodology for Sound-based Web Archives." Digital Humanities Quarterly, vol. 8, no. 2, 2014. Accessible at http://www.digitalhumanities.org/dhq/vol/8/2/000173/000173.html
Oliveros, Pauline. "Acoustic and Virtual Space as an Element of Music." Leonardo Music Journal, vol. 5, 1995, pp. 19-22. More information at The Deep Listening Institute.
Schaeffer, Pierre. "Acousmatics." Audio Culture: Readings in Modern Music, edited by Christophe Cox and Daniel Warner, Continuum Press, 2004, pp. 76-81.
Art of Noise, The
by Luigi Russolo, 1913. Many consider this letter / futurist manifesto as the start of sound art, because of its insistence on the musical value of environment sounds(s). Download as a .PDF file.
Listening Across Disciplines
A research project based at University of Southhampton, England, that investigates the potential of listening as a legitimate and reliable methodology for research across the arts and humanities, science, social science and technology. Listening means discovery and this project examines listening in scientific and artistic perspectives as an emerging investigative approach, able to access new information.
Acoustic Territories: Sound Culture and Everyday Life (Brandon LaBelle, Continuum, 2010) Explores auditory experience as located inside cultural histories and related ideologies.
Hearing Cultures: Essays of Sound, Listening and Modernity, (Veit Erlmann, editor.
A thoughtful consideration of how sound offers a new lens through which to examine culture and complex social issues.
Listening (Jean-Luc Nancy. Fordham University Press, 2007)
Examines sound in relation to the human body. How is listening different from hearing? What does listening entail? How does what is heard differ from what is seen?