Unknown Devices - Eisei (Black)

Eisei is a spectral processor and four-voice sound generator built around four interconnected voices that Unknown Devices calls Satellites. Each Satellite contains a 20-band filterbank and its own pulse oscillator. Patch audio into Eisei and those filterbanks can reshape it; leave the inputs unpatched and the internal oscillators turn the same architecture into a polyphonic sound source. Pitching, spreading and moving the four Satellites together gives the module a distinctly harmonic side as well — somewhere between filtering, resynthesis and an unusual four-voice oscillator.

The key to understanding Eisei is Datum. Press Record and the module analyses an incoming sound across 20 frequency bands, following how the energy in each band changes over time. It doesn't save the audio itself; it saves this spectral movement. The four Satellites can then travel through the recorded Datum like separate playheads on a disc, each with its own position, speed and direction. You can loop a small section, manually scrub through it with the large Time wheel or let the four voices drift through it at different rates.

From there, Eisei gives you broad controls for reshaping the whole spectral structure rather than asking you to manage 80 bands one by one. Spread pulls the Satellites apart in frequency, Key transposes the complete structure, while Lens changes its overall spectral balance. Further Warp functions can shift, distort, blur and reshape the result. It is a rather unique approach to spectral processing, and the module looks the part too — the large central wheel, animated display and unusual panel layout give Eisei a striking presence without making the workflow unnecessarily cryptic. A very distinctive instrument for turning spectral information into something you can play, move around and patch.

Features:

• Four interconnected spectral voices / “Satellites”
• 20-band filterbank per Satellite
• Four internal pulse oscillators
• Spectral processing, filtering and resynthesis
• Datum records spectral movement rather than audio
• Eight Datum memory slots
• Independent Orbit speed and direction for the Satellites
• Large Time control for positioning and scanning through Datum
• Spread controls the frequency relationship between all four Satellites
• 1V/oct Key input for transposition
• Lens globally reshapes the spectral response
• Four Warp modes: Shift, Tanh, Shape and Blur
• External audio processing or self-contained oscillator operation
• Filterbanks can also be pinged
• 6 CV inputs, 3 trigger/gate inputs
• 3 audio inputs
• 4 individual audio outputs plus summed output
• 127 × 127 px monochrome OLED display
• 48 kHz / 16-bit audio