Blinds: Premium oscillators for the Korg Prologue

The Korg Prologue, their flagship analog synthesizer, is the first to offer customizable digital oscillators and effects in addition to the analog ones. You can now upload additional oscillators with the Prologue Sound Librarian and start using them in the Multi section of your Prologue.

MULTI Engine Type Display

While many great sounds come from the classic waveforms available in analog oscillators (the sawtooth, the triangle, the square), they are always the same and are mostly static. Custom oscillators have the power to enhance your sounds, adding interesting harmonics and textures, and even be the centerpiece.

Except, there are not too many choices of custom oscillators available. We wanted to change that and to open up a whole new world of possibilities with a premium macro-oscillator made by real musicians for real musiciansNow you can make the most out of your investment into the Prologue.

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What is Blinds?

The idea of Blinds is to create living, evolving sounds through 8 wave shaping modes that can be animated with the Shape knob as well as by the Prologue’s LFO and Blinds’ own LFO.

Think of Blinds as PWM for any waveform, as waveform drawing or as live wavetable generation. You won’t find this in traditional synthesizers, not even most digital ones. Make the waves dance.

PWM stands for Pulse Width Modulation but you don’t even have to know that to enjoy Blinds.

Have there been updates?

Yes. We have kept Blinds updated at no additional charge for existing owners. Since its v1.0 release in August 2018, we have added an internal LFO in v1.1, and six new wave shaping modes in v1.2 that turn Blinds into an audio synthesis Swiss army knife.

What are the different modes?

#1 — Blinds

Blinds Mode, Cosine + Sine, 1 place

The Blinds mode allows you to mix two different waveforms in a creative way, leading to either rough timbres or subtle variations. You choose two waveforms amongst a large set, the first one is called the Front Wave and the second one is called the Back Wave. You can then progressively transform the first one into the second one by opening a “blind” in the center of the waveform, using manually the Shape knob or leaving it to the Prologue’s LFO shape modulation, to Blinds’ internal LFO shape modulation, or both. A similar idea, applied to the monophonic and modular context, was introduced by Dove Audio in their Window Transform Function project that we recommend if you are more into modular.

Blinds Mode, Square + Inverted Square, 1 place

You can also expand the possibilities by using the parameters: you can invert the Back Wave, which is useful to modulate a waveform against itself, and set the number of openings to two instead of one with the Places parameter.

The best way to understand how you are interacting with the waveforms is to look at the gorgeous oscilloscope integrated on the Prologue.

#2 — Warp / Smudge

Warp Mode, Sine, 2 places

The innovative Warp mode (we also call it the Smudge mode) allows you to get another kind of modulation similar to PWM, this time using only the Front Wave. It is modulated, or warped, as if you were smudging it from the center with your finger, left and right, depending on the Shape parameter.

#3 — Rectify

The Rectify mode, using only the Front Wave, inverts the signal below a certain positive threshold that can be varied by the Shape parameter.

#4 — Fold

The Fold mode, using only the Front Wave, inverts the signal clipping outside positive and negative thresholds that can be varied by the Shape parameter. The Places parameter can be used to invert a second time a half of the inverted signal.

#5 — Invert

The Invert mode, using only the Front Wave, inverts the left part of the waveform, whose width depends on the Shape parameter.

#6 — Mirror

The Mirror mode, using only the Front Wave, mirrors the waveform in its left part, whose width depends on the Shape parameter.

#7 — Mix & Phase

The Mix & Phase mode mixes together the Front Wave and the Back Wave to create new waveforms, with the Shape parameter controlling the phase of the Back Wave with respect to the Front Wave.

#8 — Soft Clip

The Soft Clip mode, using only the Front Wave, applies a soft clip on the signal, whose strength depends on the Shape parameter.

Finally you can bring to the Prologue an innovative waveshaping engine that is unheard of in traditional synths. Create an infinite amount of wave shapes.
Gift a fresh perspective to your creative process.

In the video below, music gear YouTuber Ron Cavagnaro showcases the 8 different modes.

What are the requirements?

Blinds is compatible with both Korg Prologue 8 and Korg Prologue 16, with the latest firmware installed (at least v1.2, voice update included).

Featured by KORG on their official Facebook pages

What is the complete list of features?

Warp Mode with a complex waveform

The Shape value, modified with the Multi Engine’s Shape knob, works in many ways. It generally defines the strength, the size or the threshold of the wave shaping techniques. Please check each mode’s description for more information.

It is also possible to automate the change of the Shape parameter by using the Prologue’s LFO. Enable All or Multi as the LFO Target OSC via the Edit button then Button 5. It is also possible to use Blinds’ own LFO feature to automatically change the Shape parameter.

There are also six Multi Engine dedicated parameters, accessible via the Edit button then Button 7.

Blinds Mode, Sawtooth + Squaretooth, 1 place

The Front Wave parameter allows to choose amongst 101 waveforms. You will find the usual suspects, such as the Square, the Sawtooth, the Triangle, the Sine, but also newcomers: the Squaretooth, the Squaretriangle and the Squaresine with increased harmonics and nice graphic shapes. You will also find DC waves (DC Zero, DC Max) that make no sound by themselves but are very useful once used with any other waveform in the Blinds mode.

The Back Wave parameter allows to choose amongst the same waveforms.

The Invert Back allows to invert the Back Wave, which is useful when the Front Wave and the Back Wave are the same. Value 1 means inversion disabled and value 2 means inversion enabled.

Pro Tip: When you first use the Blinds mode, think about changing right away either of the waves, or inverting the Back Wave, because if you open the blinds over the exact same waveform, the sound will not change.

Selecting a Front Wave and a Back Wave
Blinds Mode, Square + Inverted Square, 2 places

The Places number allows to select in how many places, from one to two, will the wave shaping take place in some modes. In Blinds mode, it means how many blinds will be opened in the waveform. In Warp mode, it means how many places will be used as warp centers. Value 1 means one place at the 50% location and value 2 means two places, respectively at the 25% and 75% locations. In Fold mode, it means how many folds will be made.

NEW with v1.2 — Six new wave shaping modes have been added.

Warp Mode, Triangle, 1 place

The Mode setting allows to activate one of Blinds’ many powerful modes.
1: Blinds
2: Warp / Smudge
3: Rectify
4: Fold
5: Invert
6: Mirror
7: Mix & Phase
8: Soft Clip

NEW with v1.1 — By popular request, a new modulation source has been added. It can be set through the two following parameters.

The Sine LFO Amount allows you to set the percentage of shape modulation, from 0% to 100%, made by Blind’s own LFO with a Sine shape. This LFO can be used in parallel to the Prologue’s Saw/Triangle/Square LFO. You can use this second modulation source to either have a polyrhythmic modulation of the Shape with both LFOs, or to use the Prologue’s own LFO to modulate the pitch or the cutoff while Blinds’ LFO modulates the shape.

The Sine LFO Frequency, modified with the Shift + Shape knob combination, sets the frequency of the Sine LFO within a very wide range, up to the audio domain.

Waves Reference List

1: Square
2: Square Third
3: Triangle
4: Sawtooth
5: DC Zero
6: DC Max

7: White Noise
8: Squaretriangle
9: Squaretooth
10: Squaresine
11: Cosine
12: Sine
etc. up to 101
Blinds Mode with the Squaresine

It is time to upgrade your Prologue to the next level.

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How does it sound?

While it was inspired by the evolving “transwaves” found on the cult classic Ensoniq Fizmo, some say this oscillator creates sounds reminiscent of the PPG Wave, but Blinds really is its own beast.
Go ahead and listen to it.

These demos are focused on the Blinds oscillator. They do not feature the Prologue analog oscillators. They are recorded straight from the Prologue’s output.

Demos #1, #2 and #3 use different voice modes and sometimes a little reverb from the Prologue, yet no envelope and no analog filter. Demo #1 is a sequence of musical bits made with either the Blinds mode and the Warp mode. Demo #2 is an arpeggio made entirely with the Blinds mode, while Demo #3 is an arpeggio made entirely with the Warp mode.

Demo #4 does not use the filter, the effects section of the Prologue, nor any voice mode variation, it only uses the Blinds oscillator and the Shape LFO. It showcases how you can use Blinds in a static way to fine-tune the waveform by morphing it, and how you can use it in an animated way, similar to a wavetable.

Demo #5 plays the 101 raw waveforms available in the Blinds oscillator, without any kind of effect or modulation.

Remember, Blinds is an oscillator, not a presets bank. It is the main brick you use to build your own sounds, knowing that you can layer it with the two analog oscillators, play with the voice mode, spread and depth, use the onboard effects, change the enveloppes, add the analog filter. Therefore those recordings should not be compared to presets, but rather to the three standard static oscillators, the sawtooth, the triangle and the square. Keeping this in mind, you will easily contemplate the vast array of possibilities.

The video below shows the Blinds mode used with identical Front and Back waves, which works well if the Back wave is inverted. This is just one of the many ways to use the Blinds mode.

In this follow-up video, other features are used, such as the Warp mode, the additional LFO, the Blinds mode with different Front and Back waves.

Now, sky’s the limit with waveforms.

What do people think about it?

User review on
User review on a Korg Prologue user group on Facebook

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Can I try it?

Sure. Give a try to the demo. While limited to 2 waveforms and not offering the vast possibilities of the 101 waveforms, it will give you a quick look at the technique and the parameters, with a Square wave and a Square Third wave (same shape as the first with only a third of the amplitude).

Pro Tip: When starting to experiment with Blinds, it is advised to start from an Init Program (empty slot) or, if you activate the Panel mode (keep the SHIFT button pressed and press the WRITE button), to bring down VCO1 and VCO2 and bring up MULTI in the mixer, to set the Resonance knob to the minimum and the Cutoff knob to the maximum. If you start using the Blinds mode, set the Front Wave and Back Waves to different waveforms, set the Shape knob to the left position, and start moving it to the right to hear, and see on the oscilloscope, the Back Wave getting progressively over the Front Wave.

Here are some ideas you can try with the demo. In Blinds mode (Warp mode parameter set to 1), use the Square (waveform #1) both in front and in the back, invert the Back Wave, then modulate Shape manually or with a triangle LFO. Try it with 1 or 2 Places. Then try use the Square Third (waveform #2) in the back with no inversion and 1 Place. Check the difference of the Mix & Phase mode with the same waveforms. Then try the Warp mode (Warp mode parameter set to 2) and use the Square wave in front with 1 Place to get the classic PWM sound — please note that a Square waveform will not warped in 2 Places due to its shape. Then try the Rectify, Fold, Invert, Mirror and Soft Clip modes at first with the Sawtooth in front and manually change the Shape while looking at the oscilloscope to understand how these modes work.

Try the demo version

I bought Blinds. Any suggestions?

First of all, make sure that you have upgraded your Prologue’s firmware to the latest version: Prologue firmware v1.2 at least is required. Please follow Korg’s guide on how to update note, so that you do not forget the steps that apply the voice update (after the main firmware update, turn on the prologue while holding the [5], [EXIT] and [SHIFT] buttons). If you do not update the voice firmware, you will see be able to select the Blinds oscillator but the waveforms will not change when you change the parameters. Then download the Prologue Sound Librarian on Korg’s website and follow their instructions on how to send a user oscillator to your Prologue.

In order to start using Blinds, turn on your Prologue and simply select the USR setting in the MULTI ENGINE section, then use the TYPE knob until BLINDS appears on the LED display. You’re good to go.

It is also possible, and interesting, to set both the Front and the Back waves to the same waveform if you activate the Invert Back parameter.

Warp Mode with a complex waveform

Once you like what the Blinds or Warp modulation sounds like, you can activate the LFO for the Multi oscillator, set the LFO rate to quite slow at first—and then of course try faster rates—, set its shape to Triangle and set the LFO intensity to mid position so that it has the maximum and most continuous effect. When playing several notes at the same time, don’t forget to check the effect of the LFO Key Sync and LFO Voice Sync options.

You can try the following combinations, but there are thousands of interesting ones that you will be able to discover by yourself.

Blinds Mode, Triangle + Inverted Triangle, 2 places

DX Max in front + Inverted DC Max on the back (classic PWM sound)
Any wave in front + DC Zero on the back
Triangle in front + Inverted Triangle on the back
Sawtooth in front + Inverted Sawtooth on the back
Triangle in front + Sawtooth on the back
Cosine in front + Sine on the back
Square in front + Inverted Square on the back, 2 Places
Squaresine in front + Sine on the back, 2 Places
Cosine in front + Warp mode

Then of course, feel free to add envelopes, the analog filter, some reverb and delay, and bring the two analog oscillators to the mix.

Are there any presets available?

Yes. First of all you could try the following 8 presets that are made to show on the oscilloscope a quick preview of the 8 modes in Blinds for Prologue.

Blinds v1.2 Modes Demos

Then, with a much more musical outlook, the following presets pack for Prologue & Blinds is provided by Robust American Patches. It comes with an mp3 demo. Those great sounds really show the breadth of possibilities offered by Blinds.

Rotundness for Prologue & Blinds, by Robust American Patches

Please note that, due to preset format limitations (in the .prlgprog files), Prologue presets contain only the slot number of the user oscillator, not its name or identifier. This would normally prevent any sharing of presets that use a user oscillator: if the slot number you chose is not the same as the one used by the preset creator, you cannot use the preset, and you cannot fix it either, because if you manually change the user oscillator type, you lose all the parameters of the preset.

However we have developed a workaround: we generate 16 versions of each preset, one for each potential slot (16 possible positions). So if you have installed Blinds in position #1 (nice choice), you just have to send through the Prologue Sound Librarian the presets that are located in the folder “Blinds in slot 1”. The only limitation is that if you decide to change the order of those of your user oscillators that are used in presets, you will have to resend the presets made for the new slot number.