Resonance Study, 2012


Resonance Study are electronic instruments built from custom circuitry and recycled consumer electronics cases. The circuits are coupled directly to their enclosure, feeding back mechanically through their physical containers. Through resonating their own cases, the instruments are self-amplifying and exhibit unpredictable sonic behaviors sensitive to touch.

The instrument design is motivated by an interest in the limits and possibilities of interaction with technology. The design provides an interaction that is neither linear nor strictly predetermined. Coupled to the mechanical resonance of its enclosure, the circuit is open to the possibilities, invention and uncertainties of our physical interaction. Changes to the physical resonant properties of the case affect changes in the sonic behavior. The recycled consumer electronics cases suggest the possibility of a juxtaposition to the interaction provided by many contemporary technologies. 

The circuit input and output are coupled directly to the enclosure through piezo elements on the surface of the case. Transducing the electrical signal to mechanical vibration of the case and back, the piezos connect the circuit in a feedback path through the enclosure. The enclosed circuitry consists of a pitch tracker, which produces a square wave signal matching the frequency of the input signal; a variable lowpass filter offering control of the circuit's resonance; and an amplifier to drive the piezo.

Signal Flow

Pitch Tracker

The pitch tracker is built from a phase-locked loop (PLL) 4046 integrated circuit. The signal is first crudely digitized through preamplification and distortion. The PLL tracks this input signal with a voltage controlled square wave oscillator. It compares the frequency of the input signal with that of the internal oscillator, adjusting the internal oscillator according to the difference. A variable pot resistor determines the tracking speed, or how quickly the internal oscillator is adjusted.

Lowpass Filter

The lowpass filter is a simple resistor and capacitor design. A variable pot resistor determines the lowpass cutoff frequency.


The amplifier is built from a power amplifier LM386 integrated circuit. The amplifier is configured for a gain of 200 to drive the piezo transducer.

Although the instruments are amplified through the resonance of the case, an output jack provides signal output for direct sound or an external amplifier.

Pitch Tracker




A pair of instruments are brought into network with one another through physical contact. Changes in contact between the two instruments alter the feedback network and sonic behavior. The audio recording was made by taking a direct signal from each instrument and panning the two signals opposite. The amount of feedback between the two circuits spatializes the audio, establishing a relationship between common signal and perceived spatialization. The shared parts of the signal sound spatially close and the separate parts of the signal sound spatially apart.