A synthesizer manufacturing company located in the castle Schloss Ahrenthal near the town of Waldorf, Germany. They are particularly known for their Wavetable based synthesizers (created from a technology designed by Wolfgang Palm of PPG fame) such as the Wave, Microwave, MicrowaveII and the orange knob-covered beast the MicrowaveXT. They also have a line of virtual analog (VA) synthesizers known as the "Q" series.
http://www.waldorf-music.de