WMD Aperture Variable-Width Bandpass Filter Hands-On Demo

At Superbooth 16, we talked with William Mathewson of WMD about his latest Eurorack module, the Aperture variable-width bandpass filter. 

wmd-apertureThe Aperture is a variable-width bandpass filter, capable of simple filtering, self oscillation FM timbres, nasty acidic squelches, and, according to Mathewson, ‘capturing images of UFOs descending from the heavens on a cold winter’s night’.

The concept is a bandpass that ranges from transparent to gnarly, with precision controls.


  • Variable bandwidth via tactile and CV controls
  • Eight pole filter core
  • Independent resonance and self oscillation of both sides of the filter with CV
  • Feedback circuit with two modes and CV
  • Input level VCA
  • Additional CV for opening the band either side of Center
  • V/oct tracking
  • Temperature compensated
  • Dry / Wet mix for parallel filtering sounds

Here’s the official demo video:

The WMD Aperture is available now for US $350.

5 thoughts on “WMD Aperture Variable-Width Bandpass Filter Hands-On Demo

    1. This particular module’s not really all that hard to understand; It’s just like one band on a parametric equaliser, in essence. That said, do you really have to be able to understand what’s going on to be able to use something? I’m not saying that it’s not useful to be able to, but I learnt about synthesisers from downloading some free VSTs and playing about with the controls until I figured out what they did, and that worked for me.

      1. That’s pretty much how I learned too and it worked out alright. I do find some of the more esoteric eurorack things difficult to grasp still and get on better with the simpler modules. Things like using the 16 tap intellijel delays for karplus strong synthesis… nope, no idea what is going on there, but I can make pretty convincing plucky sounds without that. To be honest though, the core principles are not hard: you have some modules that make noises, some modules that shape those noises and some modules that can wiggle the knobs for you in a variety of ways. There’s not a lot more to it than that, the rest is just patching those things together in interesting ways.

  1. I’m not the biggest fan of WMD modules, but damn, this one looks great. I like the layout, the concept, the LED feedback for the BP, and the aperture aesthetic is kinda cool too.

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