Reason 4 from Propellerhead Software can best be described as an infinitely expandable studio - a native-based set of virtual devices that include synthesizers, sampler, drum machine, effects and a pattern sequencer. In short, the software acts as an expandable, all-in-one music production environment.
Each unit in the virtual rack is edited from its own front panel and multiple instances of all the modules can be opened, limited only by the host computer's processing capacity. Choosing an item from the "Create" menu places the module in the rack, logically patched into the signal chain. A single key-press will turn Reason's rack around to reveal patch points for every port on every module, allowing the user to make custom patch configurations.
New in version 4 is "thor", a multi-synthesis synthesizer with six oscillator types, four different filters, a step sequencer and a modulation matrix. RPG-8 is a monophonic arpeggiator with multiple play modes, an insert function and a pattern section. The addition of a 32-channel groove mixer allows users to affect the feel and timing of loops, which are output to the sequencer, which itself has been enhanced with multiple track lanes, vector automation, dedicated device tracks, clips, count-in and more.
The software can function either stand-alone, or as a ReWire application. Full Integration with other manufacturer's audio software via ReWire allows audio from Reason to be output to an external software workstation, for further processing and/or mixing with other audio tracks. When the overall project is ready to be saved, the whole studio setup is stored along with the music, including the associated sounds, samples, loops and drum kits.