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4ms Ensemble Oscillator (EO) (White)

¥44,900 (Tax excluded ¥ 40,818)
Unique VCO that integrates overtone composition and chord composition

Format: Eurorack
Width: 16HP
Depth: 25mm
Current: 114mA @ + 12V, 45mA @ -12V
Manual (English)

The latest firmware is You can download from.

In stock. In Stock: Ships immediately


The Ensemble Oscillator (EO) combines 16 sine wave oscillators with wave shaping such as additive synthesis, FM, phase distortion, and wave fold in a novel way to create a unique and integrated tone that does not distinguish overtones and chords. A polyphonic voice module with a different approach.

In EO, the frequency of each sine wave oscillator is assigned in a unique way to a "scale" that is a grid of frequencies set internally. The "scale" here includes the scale as a scale, but the degree of freedom in setting is much wider than that, and it is a scale like a harmonic structure, a scale with dense frequencies like a chord cluster, and a non-high range. The user can also specify the scale that the integer harmonics line up. Due to this feature, I am good at gray zone synthesis in harmony, which can be said to be timbre making by additive synthesis and chord making. Other features are as follows.

  • SelectedstairsUp to 16 sine wave based oscillators linked to different pitches
  • 3 scales divided into 30 groups can be overwritten by the user
    • 12TET: Quantize all notes in equal temperament
    • Octave: Notes are not quantized and repeat in octaves
    • Free: Notes are not quantized and repeat at intervals between the lowest and highest notes
  • Programming a custom scale with a simple method using a manual or CV / GATE keyboard (Learn)
  • 3 つ のTwist Phase Distortion effect
  • 3 つ のWarp Wave Distortion effect
  • Composed of three algorithmsCross FMModulation between oscillators
  • Mono / stereo output with selectable panning algorithm
  • With selectable algorithmsFreezeFreezing some oscillator frequencies by function
  • Two 2v / oct inputs:Pitch(After quantizing) andRoot(Before quantize)
    • High precision, temperature stable performance, 8 octave range (-2V to + 6V) Can be calibrated for any keyboard
  • 6 bipolar CV inputs (-5V to + 5V)
  • Two gate inputs to automate Learning and Freezing

Starting from a complex of pure sine waves to pulsar synthesis, or from primitive overtones and vast chords to dirty drones and rattling glitches, it produces a very diverse sound.

How to Use

Frequency Control

The Ensemble Oscillator (EO) has 16 oscillators, and the pitch of each oscillator is quantized to the selected scale.PitchDetuneAdjusts the frequency after quantizing,RootspreadAdjusts the frequency before quantizing. If the frequency set by Root is between two frequencies in the current scale,You can hear both sounds. The volume of each frequency depends on how close it is to the unquantized oscillator frequency. That is, EO does not jump from one note to the next, but between notes.cross fadeTo do it. When the quantization and sound fusion process is over,PitchDetuneControls the frequency after the quantizer.

The currently selected scale determines the frequency of each oscillator. Scales can usually be thought of as a series of notes, but EO does not have to follow Western musical scales such as chromatic or diatonic scales, and there is no restriction on note spacing. Furthermore, the range of each scale does not have to be octave etc. like a traditional scale, and can be freely set, see the explanation of Learn mode). As such, it is often useful to think of scale as a series of harmonics rather than a series of notes when using EO.

The difference between chords and harmonics is purely perceptible: when many notes are playing at the same time, we perceive them as chords. However, when multiple overtones are played at the same time, it is regarded as a rich waveform.

RootspreadCauses each oscillator to move around the grid,PitchIs the whole grid,DetuneTwists the lines of the grid.
The EO can store a total of 3 scales, 10 in 30 groups.stairsUse the switch to select a group and the knobs and jacks to select the scale within the group.
Each group has different properties such as how the scale repeats in the audible range, whether it is at frequencies associated with the 12th scale, etc.

Normally, all oscillators respond to all controls, but it is possible to freeze frequencies for some oscillators. The oscillator during the freeze isPitch, Root, Spread, Scale, Detune It does not respond to each knob operation or CV control. Twist, Warp, Cross FM, Balance Responds to waveform transformations and mixing / panning changes via knobs or CV controls. To runFreezePress the button or input the trigger signal to the jack. The button will turn blue and the frequencies of some oscillators will freeze. Pressing the button again or sending a new trigger signal cancels the freeze.

Learn Mode

All factory-programmed scales can be overwritten with user-customized scales.
Custom scale programming processLearningSay,LearnThere are two ways.

  1. Dial in to a series of pitches using the knob
  2. Use of external devices such as CV / GATE keyboard

The words under some knobs are written inside a black oval (Add Note, Fine Tune, Delete Note). These show uses in Learn Mode.

Waveshaping Sections

The waveform of each oscillator is also a sine wave by default, but with three parameters, the waveform is modified to overtones and complex tones and noise. To easily see the effect of each parameter, try adjusting the other timbre parameters and Balance to the minimum value, and listening to only one oscillator.

TwistModulates the time progression within the phase of each oscillator waveform, distorting a pure sine wave (phase shaping). How to distort the phaseRamp, Pulse, CrushSelect from three types with a switch.

WarpApplies various types of wave folding to the waveform. The method of folding isFold, Cheb, SegmentSelect from three types with a switch.

Cross FMApplies frequency modulation between oscillators. The FM algorithm isUp, All, DownSelect from three types with a switch. The FM sounds created by this feature often produce interesting sounds, as each oscillator is related in frequency to each other (quantized to the selected scale).

Shift Functions

EO has some advanced features that don't require these frequent adjustments, but make important and subtle changes to the behavior of the module.
Under the Freeze button and some knobs, there is a gold highlighted alternative name labeled. To use these features, turn the knob whileShiftPress and hold the button.
Changes to the Shift function will be saved and will survive a power down. Below is a brief description of these features.

  • #Oscillators: Set the number of active oscillators (1-16).
  • Stereo Mode: Change the panning method for each oscillator.
  • Freeze Mode: Change which subset of the oscillators are frozen.
  • Crossfading: Controls the slope shape of the crossfade curve.


The explanation of each part is displayed by mouse over. If you select "Shift", it will explain the operation while pressing the Shift button.  

Firmware & Calibration

Firmware update with audio bootloader

Ensemble Oscillator provides audio files for firmware updatesLearnYou can update by yourself by inputting from the jack.

  1. Power down the module and disconnect all cables.
  2. Output audio from your computer or smartphoneLearnConnect to jack.
  3. Maximize the output on the playback device (including volume settings such as apps).
  4. LearnFreezeWhile pressing and holding both buttons, power on the module.
  5. Make sure that the Learn button is blinking green, then release the button.
  6. Start playing the audio file. You should immediately see the animation in blue and white with the buttons.
  7. If the button turns red while the file is playing, there may be an error.
    a. Stop playback and return to the beginning of the file.
    b. Make sure the cable is inserted correctly.
    c. LearnTap the button. It will return to blinking green.
    d. Play the audio file again from the beginning.
  8. When the file loads successfully and the update is complete, the button will animate in rainbow colors.

Calibration of 1V / oct jack

Misaligned tuning when using external devices is caused by a variety of factors, even if all devices are typically 1V / oct. Each jack can also be calibrated for 1.2V / oct external devices. The procedure is very simple.

  1. Out AOut BDisconnect all cables except
  2. LearnFreezePress and hold the button down for about 2 seconds. Release the button when the color changes.
  3. LearnFlashes blue slowly.C2ThePitchType into the jack,LearnPress the button.
  4. LearnFlashes blue quickly.C4ThePitchType into the jack,LearnPress the button.
  5. FreezeFlashes blue slowly.C2ThePitchType into the jack,LearnPress the button.
  6. FreezeFlashes blue slowly.C4ThePitchType into the jack,LearnPress the button.
  7. When the calibration is complete, the blinking will turn green and the module will return to normal operation.