Collage of patch cables.
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VCV Rack & Modular Synthesis Series

Cabling Conventions in VCV Rack | a user interface note

Michael Filimowicz, PhD
Modular Synthesis
Published in
4 min readNov 24, 2020

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Photographs of modular synthesizers are replete with high density color tangles of the dozens of cables used to create complex patches, e.g.

Image of an analog modular synthesizer with messy patch cables.
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At the very start of your learning, the patches won’t be very complex, but eventually you’ll want to develop a cable management UI (user interface) strategy. In Rack, you can have multiple cables connected to one output — by CMD-clicking (Mac) or CTRL-clicking (PC) on the output — which can add to the visual snarl, and there are hardware analogies for this. In the image above, you can see connector types where multiple (called stackable) cables can be attached to a connector, but also the more typical kind where only one cable connection is possible.

Two key strategies for managing the eventual visual mess are to color code the cables, and to use mults such as the module by Bog Audio. A good module for organizing your cable colors is Count Modula’s Cable Palette. This is one of the easiest tools to use, certainly easier and faster than going into VCV Rack’s JSON files for visual presentation and modifying the code.

To use Palette, just click on a color, and the next cable you create will be that color — of course, it helps if you’ve already decided on a color scheme :~) You can use a NOTES modules as a color legend for your coding scheme.

Software user interface showing the Notes module.
You can remind yourself of your color scheme with NOTES.

Right-clicking on one of Palette’s buttons allows you to add more colors, up to a rainbow maximum (and short term memory average) of 7. If 7 isn’t enough for you, you can of course add more Palette modules, but then the point of color coding cables starts to be defeated!

Software user interface showing the palette module.
Count Modula’s Palette module for controlling cable colors

There isn’t a universal convention for color coding the various kinds of signals used in modular synthesis. Omri Cohen likes Red for Audio, Blue for Clk/Trg/Gate, Yellow for V/Oct, and Green for Modulation. If you follow along with the video tutorial sequences of someone who uses color coding, you may want to follow their conventions so your patches look more like their’s. Palette’s default setting is to switch to the next color after each cable is created, but the handy LOCK button will keep the selected color from changing until you unlock it to create a new cable color type.

Another UI strategy for cleaning up the cable mess is to use MULTs instead of attaching multiple cables to the same output. A mult is usually a very thin module that doesn’t take up much space in the rack, and can help you avoid the visual pain of tracing back cables to their origins where those origins have multiple destinations. In the Bog Audio MULT, shown below, you can have either 2 inputs with 3 signal clones of each, or a single input where the second group of 3 outputs is normalled to the top input, giving you 6 clones of the signal in total. Typically (I would think), such mults are of maximum utility when placed as close as possible to the outputs they are multiplying, at least if you are using them for UI purposes.

Below, the mono output of a MIXER is sent to MULT to provide two outputs for the inputs of cf’s MASTER module (which is a great module for quickly switching the audio off and on, while also providing gain, metering and direct out options). The MASTER then sends the final 2 channels of audio to the hardware USB breakout box. Since all of the signals below are of the audio kind, they are all the same color.

Software user interface showing Mults modules.
Mults help us to break the habit of sending multiple cables from the same output.

Everyone’s workflow and aesthetic preferences will differ of course, but if you find yourself getting annoyed at the visual mess of your cabling’s visual goulash, see if Palette and MULT can ease your eye pain.

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