Since the first half of the Twentieth Century, sound has played an increasingly important role in the crafting of narratives and the transmission of information. Sound's role in media-like radio and cinema not only caused shifts in oral communication and methods of montage, but came to play an important role in the ways that these media reconfigured spatial representation and perception. As the global communications network becomes an increasingly online flow, the internet inherits a rhetoric of remote communication and spatial contamination first nourished by early radio work. And as digitized images, both still and moving, proliferate in the visual frame of the browser, we might begin to wonder how cinema's model of audio-vision can be understood in its relationship to the online experience. As readers of hypertext, the principle structuring and orientating motor in cyberspace, how can we understand the relevance of sound to the predominantly silent online digital space that harbors both rhetorical and formal elements of radio and film?

Hypertext makes no noise. Whatever spatial imaginary it is that hypertext activates, urban or otherwise, it excludes the acoustic dimension. The silence online resembles nothing more than the outer-spatial silence of a vacuum. There is no murmur in the distance to suggest isolation; there is no room-tone as in film; there is no sonic signal interference--cosmic or terrestrial--as in radio. In fact, the bleeps and escalating rush of static accompanying log-on have an opposite meaning to similar noises in radio. What once characterized the informational informe has now become a sign of connectivity and access. The log-on noise is a rush of bits, an accelerating flow immersing the user in a new data-sphere, and resembles nothing so much as a space shuttle's noisy departure from the atmosphere and entry into the silence of a vacuum.

Older media like radio, film, and television all had specific acoustic characters owing to their accommodation of noise as a data-background. The impurity of sound in these media and the distinction between synchronous and asynchronous sound allowed for a figure-ground relationship where the sonic content of a broadcast, program, or montage leapt forward against a backdrop of interference or ambience, performing as a powerful organizer of the spatial imaginary.

How can sound resonate in the transphysical city of language? At this point, it is difficult to imagine navigation by sonar online. Hyper-sound is still a slippery and dissonant concept. The streaming sound currently available online has a compressed and fractured character. Audio streams and net radio are tapped much as faucets are opened. Real-time online audio continues to remind us of the hard-wires piping information to any online terminal. That is precisely why the term "net.radio" always rings with a note of irony: the airwaves have been brought back down to earth.

Hypertext and streaming sound are configuring cyber-space in almost opposite ways. While hypertext mobilizes the spatial imaginary into a sense of virtual urbanism, streaming sound, crushed into a low-resolution format and grounded to the physical network of telephony, returns the user to a base-physicality. Online sound does not yet inscribe virtual space but is itself inscribed by the technological conditions of that space. Cyber-space has already developed as a predominantly visual lattice of text and image, and will continue to do so for some time before acquiring an integrated acoustic dimension. It remains to be seen what artifacts the current infancy of online sound will bring to the expanding optical landscape already online.