While at the MIT Media Lab I created a magneto-acoustic instrument that used electromagnets to set 31 piano strings vibrating at precise frequencies. I found each string could be played in all of its harmonic modes, and in the unstable areas between.
Here’s a recording of one string, freely resonating while the frequency of its electromagnet changes. Notice how rich sounds and timbres bloom in the spaces between the nodes. It feels like scuba diving in the deep harmonics of just one string.
Like the Whirly-Bot, its upper notes all lay in the harmonic series above each string’s fundamental. So I tuned the fundamentals in 31-tone equal temperament, which approximates patterns of the harmonic series much better than 12-tone equal temperament. I wrote this interaction simulation to prove it to myself: