In early 1990, many people were prepared to claim that real-time audio restoration was impossible, but when CEDAR Audio released the first CEDAR System in June of that year, it supported a range of real-time processes, although only one could be run at any given time. This was soon upgraded to the CEDAR-20 system. Hosted by an off-the-shelf PC running DOS and powered by the twin 40-bit floating-point DSPs of CEDAR's own ProDSP/R-20 boards, this offered a full range of audio restoration, equalisation and dynamics processing modules. All operated in real time, allowing easy A/B comparison of the processed and unprocessed signals.
The later CEDAR for Windows system could access existing ProDSP/R-20 boards and treat them as ProDSP/E Expansion boards. This was a simple and cost-effective way to upgrade from CEDAR-20 to a CEDAR for Windows suite running multiple applications simultaneously. Users with both CEDAR-20 and CEDAR for Windows systems could run them simultaneously under Windows 3.x. In this case, the ProDSP/R-20 would support the CEDAR-20 software modules, but did not appear in the CEDAR for Windows console. The ProDSP/R-20 offered 24-bit I/O when used as a ProDSP/E and initialised under CEDAR for Windows. It returned to 20-bit operation when used to host any CEDAR-20 processes. It was not possible to run CEDAR-20 and CEDAR for Windows simultaneously under Windows 95. However, users could run CEDAR-20 as a standalone DOS application under Windows 95 provided that CEDAR for Windows was not loaded.