Important answers to the most frequently asked questions

Modular Synth Basics: How do modular systems work?

Usually modules are installed as building blocks in a rack that takes care of the power supply. Depending on their purpose, the modules offer different numbers of controls and connections for audio and CV signals. The latter are controlled voltages, i.e. voltages in the low-frequency, inaudible range. Some modules generate signals (oscillators, LFOs, etc.), while others modify them (e.g. effects, ring modulators, etc.). A striking difference to usual synthesizers, which seems unusual at first: the oscillators send their waveforms permanently and not only when a note is played.

How do I use and patch modular systems?

That‘s easy: since there are virtually no rules with modular systems, cables can be plugged into any CV port almost without exception. Most modules mark inputs and outputs differently, so it‘s easy to see where signals are being received and sent.

What are semi-modular synths?

These are synthesizers that provide inputs and outputs for CV data, but don‘t need to be patched to create sounds. Rather, the various parameters are pre-wired internally. These connections are broken by manual patching.

But many modules in the rack also offer pre-wired parameters. For example, if audio input 1 is „normalized“to audio input 2, that means audio input 2 will receive the same signal as input 1 as long as no cable is plugged into input 2.

Why are modular synths so expensive?

Of course, the purchase of a rack with basic modules first costs a lot of money. It needs oscillators and envelopes, at least one filter, maybe an effect and various tools, until a sound comes out of the synthesizer Frankenstein. There are quite a few complete systems, such as those from Dreadbox or Erica Synths, but even these come at a price for which you could easily buy several small desktop synths. But as mentioned above, a modular system usually stays in the studio for a longer time and can be modified again and again for new tasks.

How can I control my rack via computer or how do I integrate a modular system into my studio and DAW?

There are several ways to do this: On the one hand, there are various modules that take care of exactly this case. The Doepfer A-190-2 MIDI/CV interface, for example, converts MIDI data to CV. Other modules offer USB ports for direct connection to the computer. And then there are audio interfaces that allow CV signals to be sent from the DAW to the rack and received from there. You can find an overview of current DC interfaces in the table on this page.

But the CV signals themselves have to be generated by specialized software like Ableton Live or Bitwig. Alternatively you can use CV Toolkit from Spektro Audio [1], Reaktor from Native Instruments [2], SQ4 Sequence Processor from dialog audio [3], Volta from MOTU [4] or Silent Way from Expert Sleepers [5].

How do I record the output of a modular system?

Since all modules that have something to do with sound automatically provide audio outputs, you can always tap the signals and route them to your audio interface. However, depending on the scope, a mixer module in the rack can make sense to mix the output first before recording it.

Are modular systems also suitable for guitars?

Absolutely! Although the handling is certainly unfamiliar at first, but the sheer mass of available modules allows the compilation of all conceivable effects in a small space. In contrast to floor pedals, a small rack could even be much more space-saving, is easier to move around, and the power supply is taken care of via a single cable. And thanks to accessories like the ADDAC311 [6] there are even foot pedals for the rack.

What do the volt specifications on the rack mean?

Eurorack and 5U modules as well as modern complete instruments equipped with CV paths usually work with a pitch logic of one volt per octave. So if you send +1 volt into an oscillator first and then +2 volts, the tuning will change by twelve semitones. Trigger, gate and clock signals typically have a voltage of +5 volts. However, modules usually interpret significantly lower values as „active“.

With Doepfer, for example, +3 volts is enough, but it doesn‘t make any difference to introduce 8 or +10 volts either. Small differences between products of different companies do not harm the precision. The Eurorack inventor specifies the working range of its LFOs with -2.5 to +2.5 volts, envelopes cover 0 to +8 volts. Here, too, the values can vary more or less with third-party suppliers.

Signals that are too hot can be dampened with an attenuator. Many modules already have such circuits integrated directly into their CV modulation paths, sometimes including an inverter. In this case the control voltages can be additionally „reversed“, i.e. applied in positive as well as negative direction. Such a combination is sometimes called an attenuator. If there is no attenuator in the CV path, you can use an external attenuator module or, for example, a VCA or mixer, preferably with a linear characteristic. Weak signals can be boosted in level via an amplifier. If you actually come across equipment that does not work with one volt per octave and positive gate/trigger voltages, there are adapters for this. One such special case is Korg‘s MS-20, a synthesizer that works with Hz/V logic and S-triggers, also called short-circuit or negative triggers.

Are there modular systems for Android and iOS tablets?

Yes, iOS users get miRack, a comprehensive modular application based on VCV Rack. Android users, on the other hand, can fall back on the somewhat more cryptic SunVox.

Do I need a modular synth for ambient and techno?

Certainly not mandatory, but due to their completely alternative approach in contrast to ordinary synths, modular systems also lead to completely different results. Above all, the focus is not on the monitor and fancy plug-in GUIs, but on controls you can touch and the sound. You usually spend more time with that than with a plug-in, so the results are more lengthy or hypnotic and therefore perhaps more suitable for various styles. Whether this approach suits you, however, you have to find out.

Hardware is too expensive for me. Are there also good modular systems as software or plug-in?

Absolutely! And in every price range there’s something: in the magazine downloads you‘ll find the free VCV Rack app, plus the plug-in version VCV

CardinalSynth, our Voltage Modular Beat version from Cherry Audio and the semi-modular banger Aalto-Solo from Madrona Labs. When it comes to paid plug-ins, Arturia Modular V, Softube Modular and u-he‘s semi-modular bacilli are way ahead.

Are modular systems available online in the web browser?

Yes and no. There are some approaches to implement modular synths in the browser, but none of them really gives you the right feeling. The elegant pulling of the cables is simply missing. That‘s why we recommend the apps mentioned above for tablets or the standalone racks and DAW plug-ins for desktops.

How can I use modular systems live on stage?

While at home cables can be patched in peace, because even mistakes are no problem, on stage every move has to be right, so as not to irritate the audience with all too crooked pitches, disturbing sounds or wobbles in the beat. We therefore recommend a rather compact rack with a mix of „untouchable connections“, for example paths from the oscillator to filters and effects and finally to the master out, as well as „dynamic connections“that you can switch around on stage. Use a solid color for the „untouchable“group and tie all associated cables together with zip ties.

Hardware or digital? Do VST and software modular systems sound better?

No. The basis in both worlds are oscillators, filters and other sound generators and effects. The big difference is in the approach: Hardware is more haptic and thus leads to different results than mouse-based tinkering on the computer.