The original proposal

Rumble Strip

Sound Sculptural Installation proposal for
Flint Hills Children’s Festival
May 27-June 1, 2007

Kids love to run and make noise. Running a stick along fence railings is an old pastime. The Rumble Strip takes advantage of acoustic principles and the kinetics of youth to create a fun musical experience. The Strip is a four-foot wide pathway with carefully planned surface texturing, laid outdoors on firm flat ground. Traveling from one end to the other with wheels (Sonic Broom [see below], skateboard, bicycle, wheelchair, luggage, or a walking cane…) you experience tactile sound colors in composed sequences; a rubbed song.

The Strip is about 100 feet in length and is made of 10’ sections that bolt together to make for smooth transitions. The order of the sections can be changed to create different musical patterns.

The sections each have patterns of grooved surfaces; some are close to each other, some farther apart, and some are irregular. Spaces between these sections are smooth and offer little friction hence no sound, corresponding to a musical rest. Pitches in music are nothing more than discrete rhythms sped up until they form an impression of continuity; above 30 cycles per second or so you hear tone more than rhythm. The Strip will play with this ambiguity as well as provide stimulation for aural pattern recognition when sections repeat and vary.

The sections are constructed of 2’ x 4’ lengths screwed together flatwise as rectangular frames. Inside each frame lies a 2” thick expanded polystyrene; this provides support for weight on top of the surface as well as acting as an acoustic amplifier (the air bubble structure acts as a solid-state soundbox). Over the top of this solid frame lie the various pattern of textured surface boards (usually 3/8” thick hardboards). The weight of the structure and the fact that each section is bolted together means the track as a whole does not need to be anchored to the ground.

There are various ways of rubbing the surface to excite sounds from the track. For those who do not wish to don skateboard protective gear there are different kinds of Sonic Brooms. These are specially designed sticks you can hold in your hand and drag behind you as you move along the track. These are adaptations of the suitcase principle, where rolling a piece of luggage over a grooved surface uses the case itself as amplifier. These will be simple in construction and can be made (and decorated) by children in school workshops ahead of time.

A typical basic Sonic Broom would have a broom handle attached at one end with a small board. Over this board would go a block of styrofoam, all bound together with large rubber bands. By dragging the Broom behind you (or two if you are adventurous) small vibrations caused by going over the grooves will be transferred up the length of the handle, spread out across the board, and amplified to audible levels by the foam block. These are simple and, if not indestructible, then easily repairable.

A more elaborate Broom would be like a ruler attached to a shoebox principle: a long flat stick is held and rubbed over the surface. Half way up the stick, it is attached to a hollow soundbox made from plywood or cardboard. You could also make a modified Berimbau (Brazilian music stick with one string used in martial arts). The stick would be placed under slight tension by the addition of a taut string on one side passing over a resonator such as a Dixie cup. This could also be played in the traditional way as a musical instrument by striking the string with a small stick.

Any number of players can play the track at one time; some may run the entire length in a race, some stand in one place and rub a favorite section.

Safety is the number one consideration so all sharp edges and unexpected surface changes will be carefully monitored. The maximum drop at the edge would be 1.5” probably into soft grass. Minimal supervision would be needed to monitor the use of the track during festival hours.

School activities

In terms of making the structure of the track and the Sonic Brooms we need:
Transportation for large boards and wooden materials to a woodshop with storage space and basic machine tools (saw, drill, sander).
Adult help for moving pieces around.

Once basic frames have been built and a few sample surfaces attached we need a children to test the ideas in practice; seeking the best sounding materials and suggesting different patterns. If they are taking a shop class they could make these changes themselves; if not, we will make them and bring the new versions for next time.

If any kids are competent skateboarders we need their help. Likewise, any special needs children in wheelchairs who can hold a stick and offer feedback are welcome to critique the prototypes.

The Sonic Brooms are good classroom projects; we can provide basic materials, drilled as needed, and they can choose from the various models to make. They can then paint, sticker and decorate their Broom to personalize it for the event.

Prior to the school fabrication sessions I can hold a workshop for teachers in which we perform several simple improvisational sound compositions. These are my verbal instruction scores designed for any age or level of ability; some involve operations on texts, whispering and vocalizing. All have simple instructions that teachers can then go back to the classroom and use with their students.


Festival performance
While the Rumble Strip will be fun and available any time for people to play on, it will be enhanced by planned performances and additional sound-making devices.

The intended site forms a long corridor with walls on three sides. It has a special acoustic property; when you clap at one end a very clear delayed echo is returned a second later from the far wall. I will provide a simple stone lithophone to one side of the track to make percussive sounds with a resonant pitch, perfect for exciting the echo and playing with the delay. These large flat, heavy flagstones are a shist material and usually used as paving; some of them, not all, resonate with a clear tone like a xylophone. Each stone can be placed on a rubber support or hose pipe and then on the ground. Heavy beaters (wooden mallets) are used to play them.

The Berimbau instruments can be used in performance and I can also provide conch shells and flutes to have a variety of sounds. Once I know what is available I can compose a simple verbal instruction score (or with live cues) so each class can perform its own symphony for Rumble Strip and Odd and Ends.