Matt Gilbert

The Echo Bridge

This is a proposal for an installation in the walkway under the South Main Street Bridge in Greenville, South Carolina. The walkway connects The Reedy River Falls Park to the soon-to-be-open Riverplace Building, the area behind the Peace Center for Performing Arts, and the rest of downtown.


Download the proposal as a pdf (1.9 MB) or view the whole proposal below.

The Site

The walkway under the South Main Street Bridge on the south side of the Reedy has some peculiar acoustic properties. Its arched ceiling can sustain echoes for very long times and these echoes change depending on where the listener is and where a sound is made in the space. It often goes unnoticed, but it's astounding.



Walking through any downtown area involves some exploration, and some discovery. Having lived in downtown Greenville for two years, It wasn't until I came back for a visit a few years later that I noticed the echoes in this walkway. These echoes must have been an unplanned part of the construction. In a city that is becoming more and more of a well-planned urban center, this space stands out as an anomaly of luck.

I believe that an urban environment isn't just "noisy"; it can often be quite rich and beautiful, and the South Main Street Bridge is a spectacular example of this.  


The piece will be a visual display of the acoustic activity that people bring to the space. Along the ceiling, many small lights will be installed that react to whatever sounds reach them. The space is large enough so that sounds will reach these sensors at different times. The echoes will cause this to happen over and over again, generating blinking patterns that move across the ceiling.

The light patterns are determined completely by the shape of the space and the people in the space.

The main goal is to invite people to play with the space itself. Currently, it's the sounds that people introduce to the space (clapping, yelling, etc) that reveal its uniqueness, and that won't change. The piece itself won't add any of it's own sounds. The piece won't instruct people on what to do there. Once people engage the space, they can explore it as deeply as they wish.

The piece will encourage people to listen carefully to the spaces around them after they leave, and in general, to appreciate Greenville in new ways.


The Way Sounds Echo Under the Bridge and How the Lights Will Respond

The diagrams below are from An Acoustic Study of an Arched Bridge, which used a computer program to model the echoes in a space like the walkway under the South Main Street Bridge. The diagrams show how the shape of the space causes the sounds to bounce back and forth. The diagrams on the left show how a sound travels, and the diagrams on the right show how the lights will respond.


Update: The acoustics in this bridge have since disappeared, sadly. Some construction work somehow disrupted them. I know for a fact that the people working on it where not insensitive to the echoes, they just turned out to be very fragile.