A short demo video made in the office. A 30x30cm polycarbonate plate, transducer mounted somewhat offcenter. Piezo microphone attached to finger. The sound of the microphone is routed back to the transducer, and the feedback circuit is closed when the finger touches the plate. The plate has many vibrational modes, each of which has a resonance potential at a specific frequency. By moving the finger to different positions on the plate, different vibrational modes can be activated, and the mode frequency contributes to the resonance of the feedback loop. By touching the plate with a second finger (other than the one with the microphone attached), I can dampen selected vibrational modes, and thus suppress feedback on that frequency. This allows other resonance potentials to rise and become the most prominent, thereby changing the pitch of the sound we hear. In certain conditions, several vibrational modes can become approximately equal in strength, and then we will hear several frequencies at the same time. Some of the vibration modes are very closely spaced. This means that very movements of the fingers can affect the sound significantly. The instrument is this very sensitive to expressional variations in performance.

Video recorded 15. October 2020. Performer: Øyvind Brandtsegg. Alternate Text