Module Library Documentation Help

I’m working on the module library documentation for the reface library.

I have an intro, a description of signal standards, and a plan to show some basic patches you can make to get started.

They include:

\section{Wiring Modules Together}
\subsection{Sequencer-Driven Subtractive Synthesizer}
\subsection{Keyboard-Controlled FM Synthesizer}
\subsection{Drum Patterns and Mixing}
\subsection{Stereo Effects}
\subsection{Generative Sequencing}
\subsection{DAW Integration}
\subsection{Eurorack Integration}

It’s not meant to be an exhaustive tutorial, especially in the first edition of this manual, but am I missing anything obvious in this section?

After this section is just each module’s individual description.

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Also I’m writing the documentation for 1/oct right now and wondering should we just make the switch to scaling 0 = lowest A note? I intend to do that in Audulus 4, and it seems like now’s a good time as any to make the switch.

We want to make it easy for both people coming from modular to Audulus as well as people using Audulus first then going to modular to have interchangable ideas.

This wouldn’t really change anything about how the signal works - you could still go negative or positive - it would just set 0 at lowest note rather than the reference note.

Personally I’m against changing the 1/octave scale reference. I don’t see that it really will make things easier for the modular people, and it will break a lot of existing patches. It would be necessary to examine any patch that potentially used the old standard and modify it accordingly. If you feel the you must change it why not make it 0 = C0 which as far as I can tell seems to be the generally accepted reference for modular. Since modular oscillators typically have a tuning knob with a pretty wide range I’m not sure that the notion of a reference pitch makes much sense even for VCOs that track at 1v/octave.


Midi also uses A 440 as the reference point, as does most of western culture. I think there are two advantages to setting the reference note as low A.

  1. summing melodies would result in higher pitches, which is intuitive.
  2. Using A to scale means a cleaner scaling and simpler numbers to remember. C1 is 32.7032 and A1 is 27.5

HOWEVER, I think there’s really very little upside of changing the reference frequency for the Audulus 3 library in it’s final update. Now that we have a VPO conversion module in the library I think we are fine for the time being. We can gauge how people respond to it, and it might be enough.

Should I prioritize making a video about pitch and expressions for pitch?


So you’re saying since people will have to change stuff around in Audulus 4 to account for new UI changes, adapting old modules to new A-is-lowest wouldn’t be so difficult?

This is really one of the big advantages I forgot to mention - makes this much easier, which is really fun for making more expressive sequences.

I think there is a lot more leniency for changing stuff when the big number changes from 3 to 4. Like I have 3 years worth of patches with 440 as the reference frequency, why change all that now?

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I still don’t see any good reason to change. The reason the values for C are fractional is since A440 is the internationally recognized standard for pitch, any decimal value you come up with for C is necessarily rounded.

It’s not so much about what Hz it translates into, but that doing it this way would be more in line with how hardware modulars work, and it would also allow you to do things like add melodies together, which doesn’t work in the same way if some of the melody goes negative.

That would be great!

Don’t know that I’ve ever wanted to add melody lines but I can see that negative values would be a problem. I suppose that A0 (27.5Hz) would be the simplest low reference. You would still have 20 MIDI notes with negative values, but notes below A0 aren’t used much. I realize that the reference point is really somewhat arbitrary, and if you decide to change, I’ll go along, but I still don’t see the need.

I just think it doesn’t make much sense to make the change in the last library update to version 3. It just confuses things for people starting with Audulus as almost all the patches uploaded previously will still use the old reference pitch.

I think changing the library reference pitch is a suitable “line in the sand” as it were between editions.

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I would agree that if a change is necessary, it should occur when A4 is released. It may still present an issue for those wishing to use modules currently posted on the forum. It depends on whether A4 will be able to open modules created in A3. If not, then a change in the standard at version change won’t present any issues since A3 modules won’t be of any use to an A4 user anyway. If A3 modules can be opened by A4 then modules using the old standard will still be available to A4 users. You could obviously create a translator from the old standard (just an integer add if we continue to use A) or modify the module after downloading it, but it’s one more thing someone new to Audulus will have to deal with. At least it should be apparent which modules are V3 vs. V4 from the snapshots on the forum, at least for the posts that have pics. I would argue that many people new to Audulus have no previous modular experience and the change in the standard will not really be of any benefit to this group of users. Those coming to Audulus with a modular background should be more familiar with the concept of a log scale for pitch and given the variability of eurorack VCOs, should be used to different reference points.


For the tutorial, between wiring modules together and the sequencer driven synth you might want a simple knob/oscillator/speaker patch demoing the various waveforms and how the oscillator pitch is controlled by the signal from the knob. Then add a filter and look at its basic controls. Sort of an intro to the concept of modulation in general and an intro to subtractive synthesis

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I agree. It would be a real hassle for A3 users to have to reprogram their existing modules and adapt to s new standard in A3…it would be especially annoying to people that get A3 between now and A4’s release as there is a treasure trove of examples based on a different standard.

Best to wait till A4. People are more likely to find it smoother going and less likely to be confused.


Great, I’ll hang off on switching it until A4!

Without any pictures, only 10% through the introduction, and just with headers for module library and a table of contents, it’s already at 43 pages.


A lot of people don’t appreciate how much effort is required to produce good documentation. I really appreciate all the hard work. It was always a job I was good at putting off.


Is there anything that someone who’s a compentent programmer, writer, and LaTeX writer, but not a compentent modular/Auduls developer could contribute? I’m eager to help but I feel like there’s a lot of prerequisite knowledge I’m missing.

For reference I could explain the conversion from 1/o to Hz, but I can’t explain without Google thre difference between phase modulation and frequency modulation.

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