Savart’s Wheel

Last modified 8-12-2009

Savart’s Wheel, designed by Bart Hopkin, is widely acclaimed for the fact that it makes the most obtrusive, obnoxious and irritating sound ever known. The instrument is made up of a series of disks of graduated size mounted on a motorized spindle. The exposed outer edge of each disk is lined with ridged material, with ridges spaced about 1/8 inch apart.

Savart's Wheel

Savart's Wheel

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“Baby Please Don’t Go,” played on Savart’s Wheel

With the spindle rotating, the player holds a sort of plectrum against the ridges as they rotate past, resulting in some number of ridge-bumps against the plectrum per second. That frequency is the frequency you hear; it is what provides the pitch. For each differently sized disk, the ridges agitate the plectrum at a different frequency (the larger the disk, the more ridges go by per second), and so the instrument is capable of playing clear melodies.

The plectrum piece is attached to a styrofoam cup. This provides a larger, lightweight surface which acts as a soundboard, projecting the vibration that the plectrum experiences out into the air. In the photo, the plectrum/soundboard pieces (there are two of them) are seen lying in front of the main instrument.
This is one of the instruments featured in the CD Instrumentarium Hopkinis: Bart Hopkin Plays Invented Instruments. You can hear a short excerpt featuring Savart’s Wheel by activating the sound controller above.

A more complete description of Savart’s Wheel appeared in the Experimental Musical Instruments quarterly journal, Volume 11 #1, September 1995. This and all of ExMI’s back issues remain available.

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