After several years of experimentation, PJRC forum user JonathanZ has released a Teensy 4.1-based drone synth pedal using S. Christian Collins’ GeneralUser GS SoundFont bank.

Built around the Teensy Audio Adaptor Board and a 2.8″ ILI9341 touchscreen, the project leverages Kris Kasprzak’s Slider Controls for Touchscreen Displays library for its UI. manicken’s Sound Font Decoder for Teensy 4.1 also facilitated the project greatly. Source code for the ISO-Drone, as Jonathan calls it, can be found on GitHub, and an overview of its features and functionality can be seen in the video below.