Michigan Avenue Bridge

8/14/2012 | Chicago, IL

This recording was made down underneath the Michigan Avenue Bridge (now named the DuSable Bridge) next to the Chicago River along the pedestrian walkway on the south bank. Once used primarily for shipping and other commercial activities, the river is now more often used for tourism and pleasure – especially on warm summer afternoons.

The sounds of sight-seeing boats passing by (along with their tour guides) can be heard sporadically throughout the recording along with occasional voices, laughter and cars overhead. Because the road surface of the lower level of the bridge is made of steel grating, the sound of the automobile tires on the bridge is more resonant than on concrete. This distinctive sound (like a mechanical roar) is used as a structural device triggering changes or new sections of music.

Listen for another structural moment which occurs with a loud, deep metallic bang around halfway through the recording. This sounds almost like the massive weight of the bridge suddenly shifts under the load of an especially heavy truck or bus. This moment serves as an abstract mirror to the previous four minutes of the piece.