Cracking the Code on Complex Guitar Pedals

Here is a ukulele run dry through Audulus in one take, into the patch below and recorded dry in AUM.

High Noon.audulus (653.5 KB)


That’s some crazy sounding uke! :cowboy_hat_face:

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The track was a bit quiet, so I treated it with the Isotope trial software. Probably compressed it a bit too much. But no guitar pedals were armed during the test, those are just Audulus effects.

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Here’s an audio gate I put together this morning. It consists of an envelope follower fed into an attack-release module. the output of the module is compared to a threshold level and the gate goes high if the threshold is exceeded. The attack and release times are adjustable. Although it’s labeled as an audio gate, you can feed audio, an envelope or LFO signal into it, any signal will work. To use it as a noise gate use the gate output to control the signal level. It’s really pretty similar to @robertsyrett’s Audio Envelope, but the variable AR adds some functionality. In @robertsyrett’s design the slew is applied to the output but in this case the AR is applied to the signal before the threshold detector.
Audio Gate V1.0.audulus (24.9 KB)


Wow, that’s super nice! I especially like the attack/decay filter inside. :ok_hand::sob:

I was wondering, is it possible to make linear slew using z-1 filters? I tried looking it up myself but all the DSP I could find involved convolution of triangles and rectangles and I was left scratching my head about how to implement that in Audulus.

Thanks for the compliment. BTW if you have an earlier version of the uAR I put together, I think the attack and release are swapped. I did a newer version of both a linear and exponential AR here:

Note that currently they both only work for positive signals. I’m working on a design that will work for positive and negative going signals but it requires a somewhat different approach.

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I have updated my library.

Because of the exponential calculations?

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After working on it for a while, I came up with a more concise design.

It now accepts positive and negative values and I combined both linear and exponential outputs in a single module.

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Just a question here @robertsyrett and @stschoen

I see there was a major revision to the A/R or slew or whatever. Do I need to change anything in @robertsyrett’s Audio Triggered Envelope?

Also, is @stschoen’s Audio Gate still current or do I need to make alterations.

Thanks guys, just got some new pickups in and I am really looking forward to digging in a bit here. :upside_down_face:

  • After experimenting for a while I have to say, that Audio Triggered Envelope is a really excellent tool for guitars. It’s very responsive and smooth. Also useful when broken out with an ES-8. It should be a standard module in the library since it opens up a use-case world for guitar pedal interests.
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Empty Patch 4.audulus (103.6 KB) I am getting some strange behaviour. When I use this patch, I end up with a long sample playing out of only one side. But it starts about 15 seconds after my first few notes, like a looper. I imagine it has something to do with the way the knob parameters are implemented for “onset” on the reverb module.

This is the most current version of the Audio gate:

I combined the linear and exponential versions and made some alterations to the internal logic.

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That is decidedly weird. This version of the uVerb is a @biminiroad modification of my original design. He created a stereo version by doubling the mono unit and delaying one side by 2 ms. As a result, the onset of the left channel never goes below 0.002 whereas the onset of the right channel can drop to 0. For some reason when the onset is 0, it causes that delayed “ghost” echo. Since only the right channel can drop to 0, you only get the effect in one side. I don’t think I ever tested it with the onset at 0 so I never noticed it. I modified the uVerb in the patch to prevent either channel from dropping to zero:
Modified Empty Patch 4.audulus (103.8 KB)

I have been really happy with uVerb. It’s not too CPU heavy and I can drop a few of them in here and there.

Should this be posted in the modules section with an update? We have so many buried modules and some buried bug fixes. It seems to me that having a good reverb is pretty crucial.

The version of the uVerb you used is part of the reface library. Since Mark is no longer working for Audulus, I’m not certain what will happen with this version of the library at this point but I’m not sure that posting modified versions of the individual modules would be wise. In this case the “glitch” only happens if the onset is set to 0 so it shouldn’t occur often in practice. I don’t think I ever posted the original version on the new forum. I was never totally satisfied with the original uVerb. I’ve fooled around with it a couple of times but so far I haven’t been able to improve it much. Maybe it’s time to re-visit the design.

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From what I am seeing there is an explosion of DSP algorithms. What I got from Duda, was just use some. Don’t try to comprehend it – at least not all of it always, immediately.

It is hard to make the case to builders on the forum as to why the Reface library is so important. We put so much stock in the idea that a car owner who understands their car is competent. However, as talent increases, you want a good driver and a good mechanic and it is really amazing to do both at a high level, but also pretty rare.

I want to produce beautiful finished tracks often (a goal not a claim). If I was building tools I don’t think I would be “driving” enough to actually get a shot at the podium. I figure its probably fun for the racing team if they have a driver that might actually have a shot. This is not to say that I am a good driver or that I have a shot. But there has to be lots of us trying for there to even be a race.

I think some front forward offerings can seem bloated and gerrymandered underneath. The thing is though, either a filter sounds good or it doesn’t. Just the inclusion of a drive knob on the filter is a very useful feature, for example.

If I get up to perform a set, some people might know I made this tool or that tool. But really either the song is good or it isn’t. I think its a bad idea to overly emphasize DIY, just as it is somewhat empty to simply scour the tech news feeds for gear and play and throw away.

Seems to me that someone would almost have to be in good brain shape (solving equations daily) to hit those “newer” reverb algorithms. However, due to the large amount of people doing just that over the last few years, I expect there are a lot of usable math bits laying about.

I also think that because these DSP concepts are logical, even if Audulus 4 is coming, there is no wasted time working on reverb.

I like that we have two in the reface library. One that I can drop here and there, but then a larger spacial one. I wish I could work on this stuff, as it must be really fun when you build it and it sounds good. But I do think there is merit in self-limiting and sticking to a few specific interests over decades and just developing those specific roles.

I should add, I am reading this – which gets to some of the more nuanced issues with DSP rights.


Interesting read regarding the VCV licensing change. I might point out that the license applies to the actual program, not the algorithm it implements. Whether implementing the same algorithm using different code would violate the license would depend on the license terms but in general it wouldn’t. Software is subject to the protection of copyright which prohibits copying a program without permission but does not cover the underlying algorithms. A license is a contract between the software publisher and the end user specifying the terms and conditions under which the software can be used. Implementing the same algorithm without having had access to the the original application clearly wouldn’t violate the license since, if you never used the original app, you never agreed to a license. Software algorithms can however be patented (at least in the U.S.) if they meet the necessary requirements. That being said, I’m a firm believer in intellectual property rights and would never support stealing other’s work.

The uVerb is based on a 1962 paper “Natural Sounding Artificial Reverberation” by M. R. Schroeder. Later digital reverb designs, particularly the convolution based models are definitely more “natural” sounding. I briefly looked at the feasibility of building a convolution reverb in Audulus but decided that there wasn’t any practical approach given the current tools. Many of the academic papers regarding digital reverberation are written assuming that the code used is written in a conventional programming language. Sometimes it is not really possible to translate this to the Audulus DSP engine.

I agree with you regarding the need for a solid library of modules. Not everyone has the time or desire to create modules from scratch. Audulus has always included a module library for just this reason. The library has undergone several major revisions during my time with Audulus. The version currently included with the Audulus software was an attempt to minimize the footprint of the module library by using SVG graphical icons for labeling rather than text (the so-called µModule format). While this did result in much smaller modules, the labeling was a bit obscure and made it difficult to determine what all the inputs and controls on a module actually did. The reface was an effort by @biminiroad to rectify this by adopting a more text based labeling scheme. At the same time he updated and reorganized the module collection as well as put together documentation for the library. Version 4 will have a new UI design, so the module library will likely need to be updated again prior to version 4’s release. At this point I don’t know if that will be a port of the reface or a re-design. Either way it will certainly contain much of the same elements. One feature I’m hoping to see in the new version is the ability to add your own libraries to the iOS version. On the Mac, I have the standard library as well as a selection of my own and other’s modules that I use often all available from the context menu.

I believe the modular synthesis movement has called into question any stiff relation to these issues. Whether we talk about human rights, property rights, or whathaveyou; as soon as we start to dig in it gets tough.

But even rats have a sense of fair play.

Which is worse, buying a Berhinger synth because technically some patent ran out or attempting to understand how math patterns create nuanced tools for sound design by appreciating other programmer’s approaches.

From the standpoint of academic philosophy the whole thing is a bit funny. I think that when someone secures the groundwork for DSP approaches, all they need to do is pick elements that are common to various different reverbs, but also avoid copying someone’s latest twist that is hot. Taking it further, you put your own twist on it. But isn’t that common to all artistic canon’s? Isn’t it that for you to satisfy your fore-bearers you need to take into account the direction of the genre by including their contributions (or by elaborating them). Then you get the head nod approval. But the second moment is when you do something new. That’s when the ancestors applaud, no?

My point about Steve Duda was that he did seek permission in his own way and seems to be encouraging others to do the same.

Just want to add that the back history you revealed there is useful for me to understand the shape of things. Thanks.

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There is an implicit social contract involved in a patent. We as a society will allow you exclusive rights to your invention for a limited period in exchange for the freedom to copy your design after the period ends. This allows the inventor to recover his costs and hopefully make a profit while ensuring that the invention will be available to all after the patent period ends. I see nothing wrong with Behringer duplicating circuitry on which the patent has expired. That is the fundamental basis for the patent system after all. Copyright involves much the same basic principle. Because of intensive lobbying on the part of Disney, the period of time for which a copyright is valid has been extended, which I personally disagree with but in the end the copyright period will be over, and the work enters the public domain and can be used freely.
Software is a peculiar case and isn’t really well covered by either patent or copyright law. For most commercial software, protection is primarily provided by the ubiquitous “shrink-wrap” license which seeks to limit the end user’s ability to reverse engineer the software, copy it for others, or use it in ways the publisher doesn’t approve of. Purchasing an application is actually just purchasing a license to use it. You never actually own anything. Additionally the source code for most commercial software is not available and various mechanisms are available to obfuscate the machine code in ways that makes it difficult to re-use. Even so, rampant software piracy particularly in the music software industry has made it necessary for publishers to implement various forms of copy protection to prevent the theft of their product.

Both the patent and copyright systems desperately need an overhaul to make them more relevant to our modern society and eliminate the business of patent “trolls” that make a living out of buying questionable patents and then threatening to sue anyone that might potentially have infringed. The cost of litigation are so high that many businesses can’t afford to have their day in court and settle with the troll even though the patents would likely be found invalid if they were to reach trial. It amounts to legalized extortion. Similar things occur in the music industry where people are sued because a song “sounds like” one that is copyrighted. I don’t support stealing someone’s work but there has to be a limit. We only have a limited number of notes after all.

It’s funny the title of the thread though! I used to pirate everything. Then I bought a Macbook, oh, 10 maybe 15 years ago. Windows is the main problem. The “PC” was always the problem. You go to the city to the industrial/commercial area and buy a 286, loaded with pirated software, often including the OS. LOL.

I think that, with the right intentions, to wield an idea, you have to understand it. You can make use of ideas, but to truly claim an idea you must get the nod from the ancestors. Only the present lives. So we care for our culture by updating it.

Philosophically, there has been a trend to shrug at messy problems – to understand that searching for symmetries can be harmful. The whole computer culture has a problem. It wants things scientific, but language is metaphoric, so there will never be a way to code ethics. This is why I often mention DeLanda, which is just Deleuze, in terms of territories (in terms of soft and hard boarders).

If I created a synthesizer and someone came along and copied it, I wouldn’t be happy. I don’t think its simple. But I wouldn’t be happy.

Here’s the thing though: Just because I don’t like it, doesn’t mean I need to will it to be a universal law (Kant). Kant thought that any ethical claim had to be a categorical imperative. I think that this holds, but mostly for each expert culture to decide for themselves. So I am fine with other people getting behind Berlinger. But I do not identify with that community in that way.

So, the idea is to move away from “rights talk” to “goods talk.” Rights are almost defined as undebatable. Goods, by definition are debatable. The next move is not to cook up some logical edifice that tells us how to organize our cultures, but instead to dream up some suggestions, some options for us to choose based on taste, not Truth.

The other thing people have lost, is conversations are not for convincing. They are for trotting out possibly offensive views, so that you can be told why they are offensive and stop thinking that way. So I am not try to convince. It’s more like spring cleaning.

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I agree. My point was that the duplication of patented products is implicit in the very notion of the patent system. Whether this is a good or bad thing is open to debate. The very notion of intellectual property is somewhat questionable. How can one “own” an idea? If you have an idea and share it with me then in what sense does the idea I now have belong to you? How different does my concept have to be from your’s in order that it no longer belongs to you? Why should one be able to “own” a song or a written work? In what sense is a melody or a particular turn of phase personal property? I think we have no choice but to view this from a utilitarian perspective. The patent system was viewed as a way to encourage innovation, by giving inventors some incentive to share their work in return for a guarantee of exclusive use for a period of time. Similar thinking applied to the copyright system. There was never an intent to grant possession on a permanent basis. Rather both these were intended to encourage the free exchange of ideas. Prior to the patent, you tried to keep your innovations secret if possible, because once they were revealed, they were fair game for anyone to copy. Even today, much IP is protected as trade secrets rather than by the patent system.

I would also agree that “rights” is not really a very useful term in this case. One has rights only so far as the society is willing to grant them. I would like to think that ethical behavior has a basis in something other than a shared consensus about what constitutes “good” although there are certainly those who would would argue otherwise. I see far too many examples of behaviors that are socially acceptable that I personally find morally questionable and equally many behaviors that are regarded as immoral that I can’t view as bad to think that majority rule is a good way to approach the question.