Commonly pronounced ARE-TAZ it is an acronym for Real Time Audio Suite. Basically it is a newer variation on Digidedign’s Audio Suite plug-in architecture that has been in use in their host based and TDM based systems for some time. RTAS has taken it to the next logical step and used the extensive processing power of today’s computers to make these plug-ins usable in real time, which in many ways makes them almost TDM-like in operation. The distinction between RTAS and TDM plug-ins is that RTAS uses the host computer for processing whereas TDM uses proprietary dedicated DSP on hardware cards. Each method has its own price/performance/quality pros and cons.