Granular Turntables
Granular Turntables is a prototype electronic musical instrument which uses two rotating, pressure sensitive wheels to control parameters of a granular synthesizer. In granular synthesis, short segments of a given audio source are taken, transformed, and played back in rapid succession resulting in an enormous range of sonic possibilities. However, most granular synthesizers conceal these possibilities behind dense arrays of knobs. With a unique interface designed specifically for this technique, Granular Turntables seeks to provide an immediate and tactile entry point to granular synthesis while allowing experienced musicians to expressively control multiple characteristics of the sound at once.
Currently, two iterations of the instrument have been made. In the first prototype (2021), sensors connected to an Arduino Uno send data to MaxMSP running on a laptop which generates the sound. In the second (2024), the goal was to eliminate the need for the laptop to provide the experience of a “self-contained instrument” with the sound generation occurring on an embedded Bela board.
Process
When starting this project, after deciding on granular synthesis as a theme, I drew up designs for how I would want to control a granulator and what sort of gestures I wanted to be mapped to what. I decided to explore a twisting-pressing motion as I thought it would be particularly satisfying to play, with the overall pressure controlling volume/sound density and the rotation “scrubbing through” the sound. Then I began working out the mechanics of an individual wheel, determining what type of sensors I would need to accomplish this (FSRs and rotary encoders) and cutting out various layers of MDF using a laser cutter. After assembling a working wheel, I connected it to the Arduino and wrote code to send the analog signals from the FSRs and position value of the rotary encoders over to MaxMSP where they could be scaled and processed to control a modified granular patch I already had. After some tuning and refinement, I had a working prototype.
For the second iteration, I already had a concept to go off of and the challenge was implementing this in a new format and improving the design. In the interim between versions I had added LED displays and was also interested in exploring haptic snap points to the wheels though this feature ultimately did not make it into this version. Since a primary goal of version 2.0 was to remove the need for a laptop, I would need a more advanced microprocessor that could handle running a granular synthesizer as well as a control interface that let the user navigate options such as audio sample selection. In order to accommodate these features, I tried several options such as the Teensy 4.1 and Daisy Seed before ultimately settling on the Bela due to its ease of use for audio development with an Arduino to handle the LEDs and UI. A major challenge for this project was the integration of all the components, physical wiring, and power draw, all of which proved more challenging than anticipated given the number of features I had hoped to incorporate. Nevertheless, I was able to achieve my goal of creating a self contained version of the initial concept with several additional features (improved robustness, menu selection, audio input for recording new samples).