Modular synthesizers are electronic music instruments made up of individual modules that can be connected in various ways. Each module typically serves a specific function, such as generating sound, shaping audio, or controlling parameters. Users can customize their setup by choosing different modules, allowing for a unique sound and creative flexibility. These synthesizers operate using patch cables to connect the modules, enabling users to create complex signal paths. This hands-on approach encourages experimentation and exploration, making modular synthesizers popular among musicians and sound designers who enjoy crafting their own sonic landscapes.