NON-SCARY INTRO EURORACK

AKA Modular is Not a Dirty Word ello, my name is Quinn, I make music under the name Wyram, and I love working with Eurorack Modular Synthesizers. Not only do I think Eurorack modular manufacturers are creating some of the most interesting music technology of today, but I also find that using them leads you to creative decisions about music you otherwise wouldn’t have ever explored. If you’re interested in getting into modular synthesis, but the thought of keeping track of that many patch cables scares you a bit, fear not! This guide should help you get on the right track to building your first modular system.

How does a Eurorack system work anyway, you might ask?

Well, the biggest difference between modular systems and regular hardware or software is that you won’t be able to make any music with them right out of the box. Your system will be made up of individual modules that need to be mounted in a case with a power supply, and you have to physically create the signal flow for both audio and control sources manually with patch cables. The modules can range wildly based on their functionality, with some of them converting MIDI messages to control voltage or converting your signal to a line-level output, to traditional synthesizer building blocks like oscillators, filters, and envelopes, to bizarre devices like probabilistic sequencers and bioelectricity interfaces. The biggest advantage of working with a modular system is because you can reconfigure the signal flow however you like, you can alter the sounds and functionality of your system drastically all while using the same set of modules.

The main thing to remember about modular systems is the difference between control voltage signals (and the various types of them) and audio signals. Let’s imagine a simple system with a MIDI to CV interface, oscillator, filter, voltagecontrolled amplifier, envelope generator, and an output module. The MIDI module will at the very least have an output for pitch (usually labeled 1volt/octave) that you’ll need to patch to the pitch input on the oscillator, and one for gate messages (whether the note is on or off) that you’ll want to patch into the gate input of the envelope generator module. Your oscillator might have a single audio output jack, or separate ones for each waveform it can produce, but you’ll have to patch one of these to the audio input of your filter module, and then out of the filter into the audio input of your VCA, and again out from there into the input of your output module to convert it to line level. There are just a couple more things to

Hpatch to get sound to come out of your system, which are patching the envelope output of your envelope generator into the CV inputs on both the VCA and filter module. Now, your gate signal has been converted into a more complex envelope shape, and you should be able to play the mono synth you’ve just built!

Now that I’ve introduced you to how it all works, here are the steps that I’d take if I were starting my modular journey today:

Step 0: Try a software emulation first.

VCV Rack 2 is the one that I use most often, and it just so happens to be mostly free! There are other popular emulations like Voltage Modular and Reaktor Blocks you can try as well. I call this step 0 because it’s a low-stakes way to begin to wrap your head around the workflow of modular synthesis, so you can see if it actually works well with your creative process before making the financial investment of building a hardware system.

The software emulations can technically be even more powerful than a physical system, but so many people choose to build hardware systems because physically interacting with them is such a big part of the experience (and it’s certainly more pleasant that navigating one with a mouse and keyboard).

Step 1: Choose a purpose for your system.

The most important question you want to answer when diving into Eurorack is; what’s the purpose of my modular system? Are you trying to build a fantastic sounding mono synth with tons of modulation options? Are you creating a custom groovebox or performance-oriented sequencer/synth combo? Are you making a sound design station to discover new tones? Or are you making an infinitely generative ambient machine to be played by mushrooms? If you can answer this question as specifically as possible, you can choose your modules with a sense of purpose and efficiency. I wouldn’t suggest picking all of the modules you want to use quite yet, because you have to make sure you have enough room in your case for them, but I would definitely look into your options in order to build your system. If you also want to keep your budget in check for your first system, you can still find a ton of awesome but inexpensive modules from manufacturers like Ladik.eu, Tesseract Modular, Blue Lantern, and Doepfer.

Step 2: Choose a case.

Eurorack cases present your first big financial investment, but there are a ton of reasonably priced options to get your foot in the door. The biggest thing to consider when choosing a case is its size, which in Eurorack terms is measured in HP (width) and U (Height). You probably noticed that Eurorack modules come in only two heights (3U and 1U) but can vary wildly when it comes to width (anywhere from 2 HP to 64 HP), and that cases can be as small as a single 3U row with 84 HP up to monster 21 U walls. Fortunately, there are a good number of inexpensive starter options available these days, like the Intellijel 4U Palette Case, Tiptop Audio Mantis, or Crea8 Audio Nifty Case, which are all great starter options because of their built-in power supplies, and in the case of the Palette and Nifty Cases their built-in utilities for things like MIDI and audio outputs.

Step 3: Plan things out first using Modulargrid.net.

This website is one of the best resources out there for building your own modular system, because it lets you make sure the modules you want will actually all fit in the case you’ve chosen, as well as making sure your modules don’t exceed the limitations of your power supply! You can create a virtual representation of whichever case you’ve purchased, and then fill it up with the website’s database of nearly every module ever created using the super flexible search function. Be aware that some of the modules you’ll find on modular grid are discontinued or not yet available, so you may have to do some editing based on what you’ll actually be able to get your hands on.

Step 4: Don’t forget accessories.

This one might seem obvious, but you’re going to need patch cables for your system, and probably a lot more than you think. It’s also pretty important to get a lot of cables of different lengths to actually reach modules that are far from each other, or not to get in the way of the knobs and switches of modules that are closer. You might also want to grab a few stackable cables and splitters, especially if you didn’t have room for enough mult modules in the system itself. Also, if you want the whole thing to be portable, a bag or road case that fits your system definitely can’t hurt!

ADDITIONAL HELPFUL RESOURCES: http://ladik.ladik.eu https://vcvrack.com https://www.modulargrid.net https://www.tesseractmodular.com https://www.bluelanternstore.com https://doepfer.de/home_e.htm https://tiptopaudio.com/mantis https://intellijel.com/shop/cases/4u/4upalette-eurorack-case https://www.cre8audio.com/niftycase

Stephen B. Ward

Envelope Generators, or EGs, create a control signal that rises and falls over time when a note is triggered. In a synthesizer, that signal can control an amplifier to shape loudness changes over time. It’s also common to raise and lower a filter’s cutoff frequency, so brightness changes over time. Pitch envelopes are great for creating realistic drums and interesting synth patches. But there are dozens of other things we can control with EGs and having multiple envelope generators allows control of multiple parameters in different ways.

Three common kinds of Envelope Generators are ADSR, A-Gate-R, and Decay.

An ADSR EG gives you full control over attack time, decay time, sustain level, and release time. Attack controls the time it takes to go from 0 to 100% level. Decay controls the time it takes to go from 100% level to the sustain level. Sustain controls the level where the note settles; set it low for more punch, or higher for a more compressed sound. Release controls the time it takes to go from the sustain level back to minimum after the note is over.

An A-Gate-R EG allows control of attack and release times and assumes sustain level at maximum. Some EGs of this type allow you to switch from gate to trigger mode and will begin to release as soon as the attack is over.

A Decay EG assumes an instant attack time and no sustain; you only control decay time. For 90% of percussion sounds and plucked stringed instruments, that’s really all you need. The classic Acid House bass machine, the Roland

TB-303, had a simple Decay EG. Decay EGs are also great for filters.

Let’s think for a moment about the physics of how acoustic instruments produce sound. You can divide them into two camps: instruments that allow players to keep feeding energy into them so they can sustain, and those that only allow energy at the beginning of the note. Wind instruments, such as woodwinds, brass, pipe organs, and the human voice, can all sustain as long as the wind keeps coming. Similarly, bowed stringed instruments, can sustain as long as the bow keeps moving. Electronic instruments keep sustaining as long as you pay the electricity bill!

Electric organs use a gate-type envelope, with minimum attack and release times, and maximum sustain level. If you are using an ADSR envelope, the decay setting is arbitrary, because sustain is at maximum. Pipe organs are similar, but because the air in the pipe has inertia, it takes a few milliseconds to get it to move and to stop moving. For this reason, use short attack and release times—and a ton of reverberation. Since the lower-pitched pipes are longer, they have longer attack times than higher pitches.

Wind instruments also have a column of air to move—a trumpet uses about five feet of tubing, for example. Once the air gets going, it doesn’t take as much force to keep it sustaining, so there tends to be a slight drop in level during the note’s sustain as compared to its attack. Start with medium-short attack and release times, set the sustain level relatively high, say 70–85 percent, and match the decay to the release time. Again, lower instruments have longer air columns, so lengthen the attack, decay, and release times. Tuba is two octaves below the trumpet, so the air column is four times longer and times should increase proportionally.

For plucked, hammered, or strummed strings, mallet instruments, and most percussion sounds, all the energy is put in at the start of the note and loudness necessarily decreases over time. There is an instant attack time, and no sustain level. Because decay time is the only thing you need to adjust, you can use a Decay EG, or if using an ADSR EG, set attack and sustain to minimum, and match the release time to the decay time. That way, it won’t matter whether you hold the note, or let it go early. For Bass, Guitar, and Piano sounds, you probably want long decay and relatively short release times. This simulates damping by the player at the end of the note.

These are just some examples of how to manipulate your synth’s envelope generators to approximate sounds of instruments you know and love – but of course half the fun of playing synthesizers is to experiment and come up with brand-new sounds.