In 1990, Rodgers introduced software-based digital church organs with technology which connected multiple Digital Signal Processors (DSP) in parallel to generate pipe organ sound with stereo imaging. Sounds in other digital organs are derived from DSPs in either a sampled or synthesis type generation system. Sampled technologies use sounds recorded from various ranks of pipe organs. In synthesis systems, the wave shape is created by tone generators instead of using a sound sample. Both systems generate organ tones, sometimes in stereo in better systems, rather than simply playing recorded tones as a simple digital keyboard sampler might do. Marketed by Eminent, Wyvern, Copeman Hart, Cantor, and Van der Pole in Europe, synthesis organs may use circuitry purchased from Musicom, an English supply company. In the digital organ category, synthesis-based systems are rarely seen outside of Europe.
