Greg’s Harp: An Instrument With No Description

If you’ve followed this blog, you know that I love to focus on unusual musical instruments. This is because someday one by defy the odds and become a standard in some way, or it just might be used for something otherworldly by a sound designer or composer. One instrument that falls into the “no description” category is Greg’s Harp.

Greg’s Harp is a robotic stringed instrument featuring a unique concept in that it has motorized frets. There are three strings that can be played simultaneously to play a triad in all inversions thanks to a unique design. There are four motorized frets (or moFrets by creator Frank Piesi) that equals five semitones per string. The strings are tuned in major thirds, making them overlap one tone (so that strings 1 and 2 and strings 2 and 3 have one tone in common). A software algorithm takes incoming notes, analyses them, then sends a playable inversion to the moFret controller.

What’s especially interesting here is that the strings can be “played” in three different ways: solenoids that strike the strings; an “eBow” coil stimulator; and a small motor with plastic plectra that plucks the strings. Sound is picked up by piezo transducers, and everything is controlled by a pair of Nanos and a Teensy development board for DSP processing, which takes care of MIDI duties.

The strings are picked up by commonly available piezo elements connected to a preamp circuit, both embedded in the bridge. Piezos are ideal for this application because they have the advantage of not picking up the electromagnetic noise from the motors and coils.

Check out the video below to hear Greg’s Harp in action. You can also take a look at Frank’s page about the instrument that provides plenty of information about its concept and construction, as well as up-close detailed pictures.

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