DAFx 2020

Hey all,

The DAFx (Digital Audio Effects) 2020 conference is happening this coming week. Due to… well, you all know why… the conference will be happening online, and will be entirely free! There’s a ton of really interesting research being presented, but here’s a few things I thought might be interesting to the VCV Rack folks:

Virtual Analog:

  • Taming the Red Llama: The first VA model of a CMOS inverter circuit (at least that I’ve seen)
  • Antiderivative Antialiasing in Nonlinear Wave Digital Filters: WDFs are a really cool circuit modelling paradigm, and Antiderivative Antialiasing (ADAA) is a great way to reduce aliasing artifacts without only a modest amount of oversampling.
  • Moog Ladder Filter Generalizations: A more general way to look at the Moog Ladder architecture, with some neat-looking results. (If you’re not already familiar with Kurt Werner’s work, definitely look at more of his papers, he’s fantastic)

General DSP:

For Rack itself:

  • GPGPU Patterns for Serial and Parallel Audio Effects: I believe there’s been some talk about potentially using GPU’s to improve the performance of Rack’s audio processing, which hasn’t really panned out. I don’t claim to fully understand it, but this paper seems to have figured out some tricks for using GPU’s for improving the performance of running multiple instances of audio plugins. I know the author a little bit, if anyone wants to get in touch with him about this.

Also (shameless plug), I’ve got a couple of my own papers at this year’s conference as well: a more technical paper on nonlinear filters, and a much sillier paper on water bottle synthesis.

Hope to see you there!


Oh yeah, please do! It’s incredibly simple yet quite amazing! :+1::grin:


geez - your profile says “I’m a musician from Denver”, not “I’m a guy a CCRMA” :wink:

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Oh, I think I’ve been to your city! Is Lausanne the place where Kudelski group is located?

Yep! :+1:

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Love the water bottle synthesis.

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I converted the VST to a module for Rack in the last hour, with polyphony and SIMD for good performance… this thing is nasty :stuck_out_tongue:


I hoped (almost expected) you’d get your hands on this. Thanks.

Love it and already broke it :wink:

Nice! Can’t wait to try it!

Yeah, I ran into this issue to with the VST version too, seems to be unfortunately easy to get it to go unstable. I’m wondering if internal oversampling or using an alpha transform could help…

(edit: it seems that they’re using the Backwards Euler transform for discretization, which is typically very stable… so maybe oversampling is the answer, or limiting the range of the input gain.)

Haha, technically I’m from Denver originally, but I’ve been up and down California for most of the last 6 years… but I still “feel” like I’m from Denver. Just finished my program at CCRMA though, so we’ll see what’s next!

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I had a lot of fun visiting on a business trip in 2001 to meet with the nice people from Nagravision.

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Vult Ferox should get you most of the way there for the Red Llama. @modlfo Leonardo Laguna Ruiz has modeled a CMOS inverter with his Vult magic!

@pgatt Ferox models the CMOS inverters using FET components, just as the paper above.

Here’s a picture of me having fun modeling the Bistable system using 3D mechanics :slight_smile: