ADDAC System is one of the most experienced manufacturers of modules related to random processes or stochastic voltage generation. For a long time, their modules have been looking at this world of synthesis. The ADDAC511 is a complex module; you will need to spend a lot of time studying it and comparing it to the manual (which is excellent, by the way). But with enough practice, you can do lots of things with four voices. You can control them separately or together. The main sections let you control the voltage of each voice, the probability, the distribution, the timing of events, and much more. The "Envelope Settings" section and the sequencer are also impressive. This module is special because it is easy to use and each button is laid out clearly. It also has a lot of presets and three completely separate states for each voice, which is very important when performing in a concert. These states can be prepared and accessed very quickly, which makes the module useful for a concert. The quantizers (independent for each voice), the inputs for assigning external CV, and the inputs for logical processes (AND, OR, etc.) are also great. To put it simply, if you want to use random processes to compose music, this is a module like no other.