WTF Is Like PWM On Steroids

The WTF Oscillator lets you ‘wipe’ between two different wave shapes, sort of like PWM on steroids.

Synth designer Paula Maddox (Monowave, Modal 002) has launched a Kickstarter project to fund production of the WTF Oscillator, a new type of oscillator, in Euro and 5U formats, based on ‘Window Transform Function’.

The Window Transform Function (WTF) oscillator lets you ‘wipe transition’ between two different wave forms, a bit like PWM on steroids.

The idea is that you have two waveforms, one ‘in front’ of the other. WTF lets you ‘slide a window’ to reveal or hide the waveform ‘in back’. This lets you transition from one waveform to another in a new way, and also to create new types of waveforms.

You can also use control voltages to modulate the size of the window opening. This can be used to create PWM-style sounds, but not limited to pulse waves.

Here’s the official intro to the WTF module:

Here’s a deeper look at the WTF oscillator:

The WTF also offers a pitched noise mode:


  • 32 Waveforms + Noise – There are 32 waveforms plus noise in the module and you can morph between any two. There are of course the usual suspects – sawtooth, sine wave, triangle wave and square wave. The remaining 28 waveforms are all newly created to mimic certain types of sounds, like vocal formants, distorted waves, metallic sounds and many more.
  • CV Control of Waveforms – You can select the front and rear waveforms with independent control voltages, enabling you to create rich sonic textures.
  • Tuneable Noise – The noise is tuneable, when you enable noise for the rear wave you can adjust the frequency the noise is generated at, allowing you to go from a white noise to a retro 8 bit game console style noise.
  • Advanced ‘PWM’ – You can also set the rear window to be a DC level giving you the ability to create PWM like sounds with any of the 32 waveforms.
  • Wave Inversion – You can also invert the rear waveform which adds a whole new level of sonic capability to the WTF oscillator.
  • Dual Window Mode – you can change between a single window opening and closing or a dual window.
  • CV Control of Waveforms – change both the front and rear waveforms using control voltages.

Audio Demos:

Pricing and Availability

Production of the WTF oscillator is being funded via a Kickstarter project. The module is available to backers in Euro format for £325 and in Dotcom 5U format for £425.

25 thoughts on “WTF Is Like PWM On Steroids

  1. Too much for my blood, but man does it look awesome. Would love to see this tech make its way into synths.

    1. Absolutely not Tom… I’ve seen/heard this in action and it’s scope is HUGE. It’s actually the opposite in that as well as the very clever digital stuff, combine it with an lfo or EG and you can get some incredibly musical and organic textures out if it.

    2. Did you listen to the first audio demo?

      It shouldn’t be hard for anyone to imagine how this could be used.

      It would be nice to have more examples of the WTF in action with lfo or EG modulators, though.

    3. Yeah, the timbre isn’t bad, but it kinda just sounds like a wavefolder. A lot of money/work to get a timbre that’s already available. I mean, you could nitpick, but in a mix, no one is going to be like “Ah! This is a new type of waveform morphing!”

      1. Myself, and most people who’ve played with the oscillator think it is significantly different to a wavefolder. This lets you choose which waveforms to insert rather than relying on distortion techniques, you can also control the ‘width’ of this which is not so easy to do with wave folding.
        But you’re entitled to your opinion 🙂

    1. Many of the most interesting modules these days are essentially running soft synths – but they are doing it on dedicated hardware, tuned to deliver performance not possible in software.

      1. Besides Pacarana, I’ve yet to see proof of that “not possible on software performance” performance. And in that case again it is probably the code not the dsp contributing..

        1. You haven’t looked very hard, then.

          Try doing audio rate modulation or zero latency or component modeling or low jitter sequencing with software running on a pc.

          Yeah, it’s the code running on your pc slowing things down and making it jittery, but it’s also a lack of dedicated horsepower in many cases.

  2. Sounds pretty great! I’m wondering though how this is different from wavetable synthesis that allows you to specify a “start” and “end” waveshape and provides interpolation between them?

    1. with wavetable synthesis a ‘linear interpolation’ (basically a cross fade) is used to morph between waveforms, with this you are ‘inserting’ a waveform into the middle of another, it has quite a different texture.

  3. Aye Paula, good to see you in the media again and hear the name Maddox is still going strong.
    Awesome module. Haven’t investigated all yet and don’t see the relationship with PWM yet. Looks like a very special form of granular synthesis or wave morphing to me, but then one in which you have extreme fine control over the resulting audio spectrum.

    Real surprise here, thanks for demoing and good luck with the kickstarter!

    1. Thanks for your kind words. There is a PWM video on the kickstarter page, but basically imagine the rear waveform is set to a DC level instead of a waveform 🙂
      Also, as you say, it could be viewed as a form of granular though you’re mixing two different grains that are in sync rather than just one grain.

      1. It’s great to see you back here again with shiny new ideas and a shiny new gender. Looking forward to more Maddox creations!

  4. Brave Paula! No easy to make this kind of changes in the sick society we are living. Hope enjoy who you are, and keep creating wonderful instruments. Cheers from Catalonia.

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