Sound maps are graphic catalogs of music, noise, local ambient color, or anything else audible. Most often based on city boundaries, they typically plot sound on a Google Map (or something similar) – as art projects, policy evidence, historical archives, or consumer tools.

In many cases, reducing sound to a visual field is a bit awkward – do we really hear better while looking at a two-dimensional picture on a screen than we would if we were actually in the space being represented? Maybe not, but the general desire to control sound is very strong, and what better way to control something than to pinpoint it? In this way, for example, compositional maps bring the urban din into a realm of aesthetic order, policy maps subject it to regulation, archival maps protect it against decay, and application maps help us navigate it. There are obvious appeals (and complexities) in each.

Below is a typology of the most common kinds of sound maps, with examples. Many of these come from recent discussions on the Sound Studies listserv, and from an item on Wayneandwax. Have I missed any important categories? Do you know of other examples?

Collaborative Documentary
This is probably the most straightforward category, and the most logical outgrowth of available technologies.

Open Sound New Orleans is a simple map of the city that allows users to upload self-recorded sounds in the categories of “voice,” “music,” and “ambient,” and to plot them where they were made. The site functions as a local forum, with an emphasis (based on the most frequently used tags) on post-Katrina revitalization, business, neighborhoods, and community. Many of the recordings are interviews. Like many sound maps in this category, Open Sound New Orleans uses sound (as opposed to text) to better emulate “being there.”

In a similar vein, overlays user-submitted field recordings on a map of New York City.

A sound map of Montreal.

Soundwalks in San Francisco, Lisbon, Istanbul, Basel, and more.

This is actually a very diverse category, and one that relies comparatively less often on mapping in the standard visual sense. For example, GPS Beatmap: Planet as Control Surface is a piece of software that uses GPS to assign musical snippets to small circles of land all over the planet. As users walk or drive around, they traverse different circles, creating a beat-matched mix as they move:

There is also a lot of politically oriented work in this category. Heidi Boisvert’s sonicWarfare hands listeners a map of midtown Manhattan, overlaid by a semi-transparent map of the section of Baghdad where U.S. troops invaded in 2002. You follow a route on the map while listening to a recording of an imaginary war – the intended effect is to make conflict seem real, even personal: “Protest in Vietnam was mobilized by images, but today images of war barbarity do not pose the same disgust, disquiet. We have become inured by the spectacle of violence paraded on TV and in movies. Why though when you see war reportage on the news are we not forced to endure the sounds of war? Is it harder to bear the pain of others through our ears … ?

Consumer Empowerment
There is something mildly unsettling to me about this category, even though I recognize its utility. is a project under development at the Audio and Acoustic Engineering Research Centre at the University of Salford, for which people are asked to add their own recordings to a large data pool for professional analysis. Sounds are also tagged by users with their own qualitative opinions. According to the site, the project “could have far reaching implications for professions and social groups ranging from urban planners to house buyers.”

As you can see at the end of the clip below, sound clips are rated from 1 to 10 in several areas, such as tranquility, activity, soundscape quality, etc. It is implied that the research could ultimately identify areas of sonic pollution, allowing them to be cleaned up through various strategies. But a rating system like this invites much subjective disagreement, since sound is notoriously prone to differences of interpretation. And subjectivity, especially in metropolitan cities, is always bound up with issues like class and ethnicity. The (very difficult) question not asked here is how we can manage sound in a way that is also socially just?

Meanwhile, GeoGraffiti is a cell phone application that allows you to “tag” any place with a voice recording. You might leave a restaurant review, an event announcement, or a funny comment. Other GeoGraffiti users passing by that same spot could then call in and hear your message.

This category essentially has two subsections: historical and natural sound. Both of these are animated by an impulse that ethnomusicology knows very well, that is, the need to save “endangered” sounds through archival preservation.

The most prominent historical effort is the BBC’s global Save Our Sounds audio map. Save Our Sounds is built on an engine much like the collaborative documentaries above; however, its purpose is explicitly ecological: “Precious sounds are dying while new ones enter our lives … So here at the BBC we want to build a sound map of the world – and save endangered sounds from extinction.”

Another site, Sydney Sidetracks, offers historical material, including sound and video, tagged to a map of Australia’s largest city. The site encourages you to “download a version to your mobile or load up your player and take the stories with you. When you next visit the city, you can listen to the crowds at Martin Place celebrating the end of WWII or watch George St., 1906, from a moving train.” Sydney Sidetracks combines documentary and artistic approaches to produce a heightened sense of verisimilitude about the past.

Preservation of natural sound has a slightly different flavor. This type of work often vilifies man-made noise, and calls for a greater appreciation of natural or environmental sound. Groups like the Right to Quiet Society call for outright abatement, while artist-researchers like Gordon Hempton (whose recordings are fantastic) pursue sonic purity and plot it geographically. Not silence, per se, but spaces where human sound is totally absent. Such a pursuit is, clearly, about more than volume. However, it is increasingly clear that the preservation of sonically “natural” space requires lots of work – campaigning for awareness, lobbying for changes in flight patterns, hiring park rangers to enforce sound restrictions in wooded areas – all of which, ironically, produces noise.

Policy Data
This is by necessity the most reductive category of sound mapping. Cities pursuing noise control need clear data that can be translated directly to enforcement. Unfortunately, this usually means maps not linked to actual sonic events, that estimate decibels based on things like infrastructure and traffic level.

San Francisco Department of Public Health, noise pollution map

Noise map of Central London

These maps are meant to help city planners be more aware of the impact of sound when making choices about zoning and construction, which is a good goal. However, acoustics (especially theoretical acoustics) can only predict so much about aural imposition.

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