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THE WALKER, detail
THE WALKER, full view
about the Springboard

Aside from my interest in the sonic potential of coil springs, I began its construction with no preconceived idea of how the Springboard should sound or look. Initially, I did not even aim to make a musical instrument. As an audio artist, I knew springs were used in reverb effects devices before digital versions became common, and I was intrigued by the everyday sounds of retracting extension springs for screen doors in homes. Large springs for garage doors were capable of producing an especially intriguing and memorable listening experience.

What developed from my experiments is a simple device for amplifying readily available objects and materials, producing a wide range of extraordinary sounds, in a way so tactile and immediate that the Springboard lent itself as easily playable. Thus, it fulfilled my definition of a musical instrument. Now, as such, more than 20 years later, though strange and unsettling for some, its unique voice continues to satisfy. People watch and listen, get inspired to make their own, and occasionally contact me for my approval or permission. I admire and I am deeply gratified by those who do ask. I am happy to grant "permission," even though I believe no one can or should have a patent on creativity of others who use everyday readily materials, including the tools and materials used to invent new instruments along with new sounds and music. I consider the Springboard "open source," so to speak. Feel free to contact me. Learning is what keeps us growing. As long as growth is happening, so is life. The more people who take my discoveries and apply them to their play and research, the greater our culture will be as long as these resources are openly shared.

The following text and photos describe and illustrate the Springboard's construction and use. I also provide resources for making your own piezo contact microphones and experimental musical instrument.

Attached across the top of an aluminum walker is a 2 x 6 (inch) board. A single piezo disk contact microphone is mounted inside a small cavity in the underside of board. By extension, the high sensitivity of the piezo pickup enables the entire board to amplify anything that touches it. Hence, the board is transformed into a receiving surface that amplifies any number of objects I choose. Among them:

    • coil springs of various sizes
    • combs
    • tuned wood slats (ala Hans Reichel's Daxophone)
    • small metal grill
    • large rubber bands

contact microphone mounted in Springboard

... all of which are bowed, plucked, rubbed or struck with brushes, chopsticks, friction mallets, or my bare fingers. With higher amplification the entire instrument is sensitive enough to pick up sounds of the room itself. I also amplify objects placed directly on it, such as a music box mechanism, large rubber bands, a vibrating massager, and a small piezo disk speaker connected to the earphone jack of a pocket radio. Essentially, any handheld object or material that vibrates, or causes a vibration to occur, will produce a sound when in contact with the board. attaching wood to board

Coil springs are a favorite source of sound. As mentioned, this inspired me to make the Springboard. When bowed, unlike strings of traditional instruments, coil springs produce a lot of enharmonic content. Instead of a single clear pitch, we hear a group or agglomeration of pitches. They are not harmonically related, and may suggest sounds similar to bells and cymbals. The frequency range spans from sub-audio (below 16Hz) to as high as any traditional acoustic instrument (near 4kHz). The piezo-pickup is sensitive enough for the frictional noise of the bow hair's movement across the springs, adding a sort of white noise component weighted in the high frequency range to the overall sound. Some listeners find bowed coil springs a "nefarious" or "haunting" tone. Some equate the sound with "special effects" for "scary movies," and "digital synthesizers." I think these responses are a common response to dissonant tone combinations. Of course, I welcome any listener to entertain and hold their own associations.

I use multiple coil springs on the Springboard. One end of each is attached to each leg of the walker with the other end of each coil spring attached to a different point on the board. Usually, I bow the springs, as well as the wooden sticks or slats. If you have not heard Hans Reichel's Daxophone, I urge you to listen. You might associate the surprising sounds with human or animal voices. Their murmuring, whining, cajoling, snoring, and growling can trigger associations both comic and disturbing. Well, so does humor come from hidden places in one's imagination.

With my Daxophone—a crude three-in-one variant of Reichel's beautifully-crafted one-stick-at-a-time instrument—I bend the pitch by applying pressure with the fingers of my non-bowing hand. The sonic results work well with saxophone players and the extended vocal techniques of my friend and musical partner, Carol Genetti.

Also worth noting that a key component to Reichel's instrument is the "dax." This handheld, oval-shaped piece of wood offers a smooth side and a fretted side. Instead of using bare fingers to modulate the pitch produced, the dax is rocked back and forth on the wood stick as it is played. With the smooth side a player produces sliding pitch changes (vibrato and glissandi). The fretted sides allows the player to find pitches at stepped intervals of the equal tempered scale.

My techniques for playing the Springboard continue to develop through practice. As a drummer I learned how to become sensitive to the material response of the Springboard. I seldom ever hit any parts of the instrument as one hits a drum. Instead, bows, brushes, friction mallets, chopsticks, my bare hands and fingers apply controlled pressure, flexion, and friction to produce its most intriguing sounds. As I mentioned, I prefer using a cello bow on coil springs rather than a plucking or striking them. As with a stringed instrument, bowing produces a harmonically richer tone than plucking a string. The same applies for bowed coil springs.

With large rubber bands stretched around the eyebolts and grill, I make sounds that are identical in range and timbre to an acoustic bass. I pluck them or use chopsticks to drum on them.

overhead view

In 1999 I began using an Oberheim Echoplex Digital Pro to sample, loop, and overdub sounds in real-time for my performances, both solo and with the Plasticene theater company. However, in free improvised ensemble performances I prefer to use the Springboard without the Echoplex. In these situations the musical flow will shift, halt, or reverse directions faster than I can respond to them with the Echoplex .

Eric playing Springboard at CIF 2006

A key inspiration for making my own instruments came from Hal Rammel, who began teaching instrument invention workshops at the Experimental Sound Studio in 1990. I had also seen and heard Nicolas Collins and Elliott Sharp perform on invented instruments of varying complexity, in concerts co-sponsored by ESS and Randolph Street Gallery in the late-80s. And prior to that I attended percussion recitals as an art student at Northern Illinois University, where it wasn't unusual to see musicians playing hubcaps, bowls, and other everyday non-musical items.

Eric playing Springboard 1998

Prior the invention of the Springboard I had been using drums, analog synthesizer, reel-to-reel tapes, prepared bass guitar, MIDI controlled samplers, drum machine, computer sequencing, turntables, 4-track cassette recorder, and environmental (or concrete) sounds as my instruments and/or materials. In the studio I would connect these devices in somewhat complex routing schemes to create recorded pieces. In that environment my studio was an instrument itself. I still use some of these devices and techniques in my teaching as well as performances and studio compositions.

The newly published Signal Culture Cook Book offer two "recipes" from Bill Sack and me, for alternative ways to make and use your own piezo contact mikes, or "piezo-pickups."

A final, important technical note about piezo electric contact microphones and impedance. This is essential for getting a good sound, especially in the lower frequency range. Piezo electric elements are ultra-high impedance devices. Without going into a lengthy explanation of electronic theory, I provide this practical information. Impedance is measured in Ohms, signified by the omega symbol Ω, or the letter “Z”. With microphones and instruments, you are dealing “high Z” or “low Z” inputs and outputs. The typical microphone input on a mixer or amplifier is low Z, and does match the high Z output impedance of an electric guitar, and especially not a piezo electric contact microphone. The resulting impedance mismatch of plugging, for example, a bass guitar into a mic input can result in a “thin” or "quacky" sound. The impedance mismatch makes it difficult to reproduce as rich a sound as the instrument may be capable across its whole frequency range. Therefore, a preamp is necessary. Commercially manufactured ones especially made for piezo pickups, such as the K & K models, work wonderfully for the Springboard. There are a bit pricey however. If you are comfortable with electronics, a DIY preamp should work just as well. Try Richard Lerman’s schematics or the similar circuit in Nicolas Collins’s Handmade Electronic Music: The Art of Hardware Hacking. Along with the preamp, it is wise to avoid long cable runs with piezo pickups, as that can increase impedance too.

In addition to Nic's wonderful book, Bart Hopkin's highly useful Getting A Bigger Sound addresses the making and use of all sorts of pickups. Visit the books and CDs page of Experimental Music Instruments to purchase this and Bart's other fine books, particularly Musical Instrument Design. I highly recommend it for anyone interested in making experimental musical instruments. It is an essential primer on musical acoustics, materials, tools, tuning systems, and more. I also recommend Bart's Making Musical Instruments with Kids. Written for adults who work and play with kids, this book features clear construction diagrams and photos for making over 60 instruments using readily available materials without need for specialized tools.


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This page was last updated on December 28, 2014.

All contents copyright 1998 - 2007 Eric Leonardson. All rights reserved.