When Oberheim designed the XK in the mid-1980s, they weren't trying to build another synthesizer—they were creating a command center for controlling multiple instruments at once, which was a pretty bold move when MIDI was still relatively new and most players were used to single-keyboard setups.
The XK is a 61-key MIDI controller built around three independent split zones, each capable of triggering different external synths or sound modules simultaneously. The keyboard itself features non-weighted synth-action keys with both attack and release velocity sensitivity plus mono aftertouch, giving you expressive control over dynamics and modulation. You get two OB-style pitch and modulation controllers—those distinctive paddle-style levers that Oberheim made famous—plus one assignable continuous control slider for additional real-time tweaking. The unit stores 100 single patches and 100 multi-patch configurations across its three zones, so you can save complex layered setups and recall them instantly.
The onboard arpeggiator is where things get interesting; it can be set to work across any single zone with internal or external clock sync, and it pairs nicely with the hold and chord modes for hands-free accompaniment while you're playing melodies. Program control and sequencer start/stop functions let you sync everything tightly with external gear. The XK outputs a single stereo audio connection and communicates via standard MIDI, making it compatible with pretty much any synth or module from that era forward.
Players have generally appreciated the XK's solid build quality and the flexibility of its three-zone architecture, though some units developed issues with their Panasonic keybeds over time—a quirk shared with other Oberheim products from that period. The controller has maintained a loyal following among vintage MIDI enthusiasts who value its hands-on workflow and the way it encourages layered, orchestral approaches to electronic music.
