Boolean is a fancy way of saying binary. Boolean logic can have only two states: high or low; 1 or 0; on or off.
Where it gets more interesting is when you apply Boolean logic to binary signals, such as clocks or note on events. A Boolean OR says if signal A or signal B are both 1 (a high signal, such as an active gate), then output a 1 (a high gate). A Boolean AND says both signal A and signal B both have to be a 1 before you will output a 1. There are Boolean logic modules available for modular synths that allow you to create more complex relationships between clocks and gates.« Back to Glossary Index