I don’t really know how else to word it, so sorry for that horrendous title, haha. Basically, I’m looking for new ways to distort sound; I’ve been working on a patch that I’m going to be using for a new harsh noise album, and it’d be nice to be able to play around with different distortions. To be clear: I have the source of the sound taken care of, but I’m looking for new effects to feed it through.
@robertsyrett, if I remember correctly, came up with a really interesting distortion effect from phasing?
Anyway, thanks for your time.
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There are some useful effects in the VCA section of the current library. Most distortion effects rely on limiting the output to -1 to 1 in some fashion and then increasing the input gain. You can use a straight clip clamp(audio,-1,1) for a harsh sound, or a tanh(audio) or atan(audio) function to provide a “soft” clip. Asymmetric distortion is also possible. ThenJFET VCA in the library is one example as is Asymmetric Distorsion Saturator. The spline based approach used in the asymmetric distortion module allows you to add additional control points and change the shape of the curve so it’s probably the most flexible.
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Here are two separate effects I have been toying with, and have used only one in a released patch. I like the way the Scrambler sounds, but haven’t found a use case. The Waveshaper is pretty neat, imo, and it will take an ordinary wave and add a lot of harmonic content to it, as it passes through the one, two, or three separate spline nodes of different shapes. Maybe you will find a use for them. I hope you will like the way they work, but lemme know what you think either way! 
Scrambler.audulus (10.4 KB)
Waveshaper.audulus (7.1 KB)
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It is worth doing a forum search for wavefolder and waveshaper.
The patches can be adapted to distortion effects – though not like standard stompbox or amp distortion – but interesting nonetheless.
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I also remembered I cooked this thing up a while ago in an attempt to mimic the environmental LFO in the TE OP-1. I like how incredibly random it makes modulates the signal, and is affected by the sound of the world around you. I made a few incremental changes and added a quick note about how it works this morning to make it a true module for distribution, and here it is. Maybe you will like this as well!
Environmentally Afflicted Modulation.audulus (10.4 KB)
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Hey, sorry I took so long to reply…thank you so much, all of you, for your replies and suggestions and patches! I really appreciate all of it!
@stevo3985, I’ll try those patches and see what’s up!
@stschoen, maybe I’m just stupid, but I don’t really get what you’re saying about clipping audio. Also, I tried to use that VCA, and I couldn’t figure out how to get it to work (again, refer to my previous statement about stupidity, haha).
@espiegel123, that’s a great idea—I’m going to do some more research into waveshaping and wavefolding first, though, just so I know exactly what I’m talking about.
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A couple of my favorites recently to get some gnarly and agressive colorization of a signal are the Feedback Mixer module (inspired by the Bastl/Casper Electronics Dark Matter) and the 10-band Resonant Equalizer. Both modules built by @stschoen.
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Here’s the actual forum posts each one was in as well. You may find some patch examples to download there as well from @stschoen, @futureaztec, and myself. Cheers!
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When I populated a through hole fuzz circuit, I knew I hit the money when I saw an asymmetrical waveform on the oscilloscope. Since we are doing digital stuff here, it can make sense just to start with the result instead of the technique. So I agree with everyone here about the idea of waveshaping.
I think it looked something like this:
I think that you also have to keep in mind how you gainstage both in and outside the box. Sometimes I need to max out the volume control inside audulus in order to get a good amount of juice going.
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Sorry if I was a bit obscure. I’ll post a better explanation when I get back to my Mac.
Audio signals in Audulus are normally in the range -1 to 1. Signals within a patch can be larger than this range, but -1 to 1 is the largest audio signal Audulus can output. When a signal exceeds this range the top and bottom of the waveform will be “clipped” off resulting in distortion. We can accomplish the same sort of thing using various functions. Here’s an example. Note that the input waveform exceeds the -1 to 1 range (it’s-1.3 to 1.3). You can see that the clamp() produces a sharper “clip” than the tanh() or atan() and that the JFET output is asymmetric.
This is the patch:
distorsion.audulus (10.5 KB)
NOTE: Since the JFET model produces asymmetric distortion, it creates a DC offset. This isn’t good for speakers so there is a DC Blocker inline with the “a” output which is used for audio. The “m” output is normally used for modulation. The spline based asymmetric unit has a similar output to the JFET.
This type of distortion is normally produced when a circuit is overdriven. Of course any modification of the input signal waveform is also distortion so various wave shapers and folders also fall into this category.
Hope this helps
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This is super helpful—thank you so much for explaining all this! And, to be fair, you weren’t being obscure: programming of any sort tends to befuddle me. Although I still use the Audulus reference pages extensively, I’m still pretty clueless, haha; I mostly just futz around and find sounds I like.
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We’re all “guilty” of this in some form or another. 
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Hi, so, sorry to bug you after all this time yet again, but I’m still trying to get that VCA to work, and for some reason it’s just…not working? Am I missing something? I basically place it in as an effect, after the main signal, but I guess I’m not doing it right?
Which VCA are you trying to use? I’ll see if I can point you in the right direction.
JFET? Sorry, I fell asleep after writing this, haha.
Hopefully this will exp[lain it. The top input and output are for the audio signal and the bottom input is for the modulation signal. The drive and feedback controls affect the distortion and the output gain (speaker) adjusts the output level. With the oscillator set on a sine wave you can adjust the feedback and drive controls and hear the distortion the JFET simulation introduces. Other input waveforms will have a more edgy sound.
JFet VCA demo.audulus (360.9 KB)
The uModule design used by the current production library was great at reducing the footprint of each module but left something to be desired as far as clarity. The next version of the module library will go back to text based labels which should make thing a bit easier to understand. This thread has some of the redesigned modules. https://discourse.audulus.com/t/audulus-3-library-reface/1455?u=stschoen
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Okay, this really helps! Again, thank you so much for all your help! I think the VCA didn’t work for me because I didn’t bother to use the modulation input—I usually tend to think of those modulation inputs as optional.
Sort of related, would you know how to add an ASDR envelope to this patch? I think I might need to add a clock to make it work, but I’m not totally sure.
Random Tones.audulus (9.6 KB)
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