This diploma thesis deals with design and implementation of complex software system for post-production of popular music. The system was implemented as a plug-in module in C++ language using JUCE application framework. The emphasis was on creating a well arranged and intuitive graphic user interface. The plug-in provides a set of audio effects and processors that can be connected into the desired graph structure. For less experienced users, there is a database of preset configurations usable for a variety of input signals.