A patch is a saved sound setting that defines how an instrument is configured at a given moment. It stores parameters such as oscillator settings, filters, modulation, and effects, allowing sounds to be recalled instantly. For example, a patch might be created for a specific bass or lead sound and then recalled during a performance or reused across multiple tracks in a studio project.

A patch bay is a routing device that allows audio and control signals to be quickly connected and reconfigured without constantly plugging and unplugging equipment. It centralises connections from instruments, processors, and interfaces, making signal flow clearer and easier to manage. For example, a patch bay can be used in a studio to route a synthesiser through different effects or processors simply by changing patch cables, saving time and keeping setups flexible and organised.