The Cellular Automata Frequency Modulation Synthesizer is a stand-alone musical instrument that harnesses elementary cellular automata, frequency modulation synthesis, and human-based musical input. This project furthers the application of CA in music by allowing CA a more nuanced role as it adds to the timbre of sound, rather than dictating the composition of music.

In a new, custom interface, Elementary CA have the ability to dynamically change the sound of this instrument. Depending on the rule, generation width, and speed at which the CA is generating, the effect the CA has on the sound varies greatly. On one end of this range, the CA has influence over the timbre of the synthesizer, and on the other, it functions more like an arpeggiator. By relieving the CA of most of their compositional responsibility, they are able to contribute to sound production much more directly - they are part of the sound, not deciding it.

As the CA are generating, the person playing the instrument can view the CA in real time with an on-board LCD screen. They can dynamically change the attributes of the CA (width, height, generation speed) and choose from one of the 256 rules. To enter pitch information into the instrument, I designed and built four ribbon controllers to control the four voices of this polyphonic instrument.

I became familiar with Elementary CA in the Nature of Code last fall. I was interested in creating interference by overlaying the CA over each other, creating moiré-esque patterns. My final project involved making applets that allowed me to 'paint' with the 256 rules of Elementary CA, controlling their color, direction of generation, width, and length and printing these compositions. In class discussions and during conversations I had with visitors at the Fall Show, people frequently mentioned that they could "hear" the prints. I began to explore how CA might sound and that exploration evolved into this project.

The challenge of this project is to find a way to translate CA into a musical form that showcases their characteristics more intuitively. In past examples, CA have been primarily used to compose music. The human composer relinquishes compositional duties to the CA. The music made in this manner seems largely arbitrary and emotionless. Additionally, past use of CA in music lacks the ability to highlight each individual rule - a listener cannot distinguish one pattern from another, reinforcing their perception of randomness in the assignment of compositional elements.

This project is for anyone, hopefully.

This instrument functions like most synthesizers. A person chooses a CA rule, adjusts other parameters (in this case: speed, length, width, harmonicity, saturation) and then makes music by pressing down on the ribbon controllers, which control notes.

This instrument is a physical computing project forged from the depths of electronic instrument design.

Elementary CA and FM Synthesis can work together harmoniously to form a unique musical instrument.