Blamsoft, with cooperation from other developers, has developed a new communication protocol for Reason. PolyCV allows polyphonic instruments to be triggered by CV. Legacy gate and note signals are limited to monophonic operation. Some existing Rack Extensions have achieved psuedo-polyphony but it is not possible to provide full MIDI-like functionality with the traditional signals. PolyCV enables full featured triggering devices. The protocol specification and reference implementation is provided freely to all Rack Extension developers for implementation in new products.
PolyCV uses gate and note cables, just like monophonic CV triggering. In fact, the same cables can be used for both PolyCV and monophonic CV. PolyCV takes advantage of the fact that monophonic gate and note signals are greater than or equal to zero and uses strictly negative signals. Multiple channels are supported, like in the MIDI protocol. PolyCV uses the concept of events, which include channel, note, and gate. A one way handshake from sender to receiver signals that PolyCV is present. This prevents bad negative inputs from triggering events. The handshake happens periodically during the idle time to allow for multi-hop connections.
• PolyCV uses the channel concept from MIDI. Multiple channels allow for special use cases, like the Polymodular System.
• PolyCV uses the same gate and note jacks as monophonic inputs and outputs. Even on existing devices it doesn’t require an extra set of jacks.
• When a PolyCV sender is plugged into a monophonic receiver the input will be completely ignored because PolyCV is strictly negative.
• A PolyCV receiver can be added to existing instruments in existing songs. Because it has a handshake, the inputs will not receive spurious notes even if an existing song has a strange input.
• A PolyCV sender can be added to existing devices in existing songs. A switch can be added on the back of the device that defaults to monophonic mode, but when switched to polyphonic mode can enable PolyCV on the same set of jacks.
• PolyCV is within the range of standard CV -1.0 to 1.0 so it will not cause strange extreme inputs and can pass through all splitters. More specifically, it is limited to -1.0 to just below 0.