Phi is a kinetic sonification of the golden ratio, also known as the golden mean, devine proportion or phi, a ratio found often in mathematics, geometry, nature, the human body and many other areas. Being an irrational number, it is approximately equal to 1.6180339887. The number can be arrived at by dividing numbers of the Fibonacci sequence (1, 1, 2, 3, 5, 8, 13, etc.). The further one progresses and divides along the sequence the closer the result is to the golden ratio. Phi sonifies this process in a musical way, relating the sequence of numbers to a sequence of scale degrees. With no people around Phi will play a rough approximation of the golden ratio (to 8 decimal points), as human activity gets closer to the machine it will become excited, playing a faster and more accurate approximation of the ratio (up to 32 decimal points).
production: Phi was produced by retrofitting solenoids to a glockenspiel. A timber frame was constructed above the keys to mount 30 24V solenoids. Custom circuit boards were made to house the MOSFET transistors required to interface the high power solenoids with the low power output of an Arduino Mega. Max/MSP software, in combination with Maxuino and Firmata for interfacing, was used to program a dynamic sequence of numbers based on the golden ratio and convert these numbers into scale degrees. A MaxSonar proximity sensor was connected to Max via the Arduino and used to detect human distance from the work. This distance reading was then used to influence the speed and accuracy of the musical sequence.