Origins and Development
The Waldorf Microwave XTk emerged from a lineage of innovative German synthesizer design that traces back to the early days of wavetable synthesis. Waldorf Electronics GmbH was founded in 1988 by Wolfgang Düren, who was then the German distributor for Palm Products GmbH (PPG), the company that pioneered wavetable synthesis under the direction of Wolfgang Palm. When PPG ceased operations in 1987, Waldorf carried forward this revolutionary synthesis technology.
The original Microwave I, released in 1989, used custom ASICs designed by Wolfgang Palm and established Waldorf as the torchbearer for wavetable synthesis. Over the following years, Waldorf developed the luxurious WAVE synthesizer (1993), which expanded wavetable capabilities to new heights but at a premium price point. The company continued to refine their technology, and in 1997 introduced the Microwave II—a fully DSP-driven wavetable synthesizer in a compact rackmount format.
The Microwave XT and XTk
Building on the Microwave II's success, Waldorf released the Microwave XT in 1998. The XT repackaged the Microwave II's engine into a striking orange 5U rackmount unit with 44 rotary encoders, bringing hands-on control to the wavetable synthesis experience. The following year, in 1999, Waldorf introduced the XTk—the keyboard version that added a 49-key velocity and aftertouch-sensitive keyboard to the powerful XT engine.
The XTk represented a significant milestone: it was the first truly affordable wavetable synthesizer with a built-in keyboard, making this distinctive synthesis technology accessible to a broader range of musicians. The instrument's bright orange panel, sleek tapering knobs, and wooden end cheeks created a visual statement that stood out in any studio or stage setup.
Design Philosophy
The XTk's design philosophy centered on hands-on immediacy. With 44 endless rotary encoders (all transmitting MIDI), performers could shape sounds in real-time without menu diving. The four-octave keyboard struck a balance between portability and playability, while the redesigned panel layout from the rackmount XT made navigation intuitive. The synthesis engine offered two oscillators per voice with access to 64 wavetables containing 64 waves each, plus 32 user-programmable wavetable slots.
The filter section was particularly powerful, offering 13 different digital filter models including 24dB and 12dB low-pass configurations, waveshaper, notch, and dual filter options. Combined with two syncable LFOs, four envelopes, and a 16-slot modulation matrix, the XTk provided sound designers with extraordinary depth.
Notable Users and Cultural Impact
The Microwave series found favor with many prominent electronic musicians. Trent Reznor of Nine Inch Nails used various Microwave models extensively, including custom 'shadow' XTk units built specifically for touring. Depeche Mode incorporated Waldorf wavetable sounds into their productions, as did The Prodigy, whose aggressive electronic dance music benefited from the Microwave's cutting digital edge.
Other notable users included Assemblage 23, who featured the XTk prominently on albums "Storm," "Defiance," and "Meta." The German techno group Scooter also utilized the Microwave series in their productions. Hans Zimmer employed the higher-end Waldorf WAVE for film scoring, helping establish wavetable synthesis as a legitimate tool for cinematic sound design.
Production History and Legacy
The XTk was produced from 1999 until approximately 2002, when Waldorf Electronics began experiencing financial difficulties. The company declared insolvency in February 2004, though a new company, Waldorf Music GmbH, was established in 2006 to carry on the legacy.
During its production run, the XTk offered a voice expansion option allowing users to increase polyphony from 10 to 30 voices. However, these expansion cards were expensive—costing nearly as much as a complete Microwave II—making fully expanded units relatively rare.
Today, the Microwave XTk is regarded as a cult classic. Its distinctive orange appearance, hands-on control surface, and unique wavetable character have made it highly sought after on the used market. The instrument's enduring popularity led Waldorf to release software emulations of the Microwave series, and in 2021 the company introduced the Waldorf M—a modern hardware synthesizer that recreates both Microwave I and II sound engines.
The XTk remains a testament to German synthesizer engineering, combining the pioneering wavetable technology of the PPG era with modern DSP implementation and performer-friendly control. For musicians seeking the unmistakable "surfing the wave" sound that defines wavetable synthesis, the Microwave XTk continues to deliver a distinctive sonic palette that spans from vintage analog warmth to futuristic digital textures.