A modulation bus refers to a system or set of patch points that are designed to facilitate the routing and distribution of control voltage (CV) signals within the module or the entire Eurorack system. The purpose of a modulation bus is to make it easier to send a single CV signal to multiple destinations or to combine and route multiple CV signals within the synthesizer.
Modulation buses can be found on certain modules or cases and can come in various forms, depending on the specific design and functionality of the system. Some examples of modulation buses include:
- Normalized connections: In some modules, certain CV inputs are internally connected (or “normalized”) to other CV inputs, so that a single CV signal can be routed to multiple destinations without the need for additional patch cables. These connections can often be overridden by patching a cable directly into the relevant input.
- Matrix mixers or CV routers: Some modules or systems feature a matrix mixer or CV routing system, which allows for flexible routing and distribution of CV signals among various inputs and outputs.
- Dedicated bus modules or cases: Some Eurorack cases or modules have dedicated bus systems that allow for the distribution of CV signals to multiple modules within the system. This can include power distribution buses that also have CV distribution functionality or dedicated bus modules that are designed specifically for CV routing.
Modulation buses allow for more efficient and flexible modulation possibilities, making it easier to create complex, evolving sounds and connections within the synthesizer.