In the past decade or so, the analog modular synth—of the kind pioneered by Robert Moog and Don Buchla—has made a comeback, creating a booming niche market full of musicians chasing the sounds of the 70s and 80s. These inscrutable racks of patchbays, oscillators, filters, etc. look to the non-initiated more like telephone operator stations of old than musical instruments. But the sounds they produce are sublime and otherworldly, with a saturated warmth unparalleled in the digital world.

But while analog technology may have perfected certain tones, one can't beat the convenience of digital recording, with its nearly unlimited multi-tracking capability, ability to save settings, and the ease of editing and arranging in the computer. Digital audio workstations have become increasingly sophisticated, able to emulate with “plug-ins” the capabilities of sought-after analog studio gear of the past. It has taken a bit longer for virtual instruments to meet this same standard, but they may be nearly there.

Only the most finely-tuned ears, for example, can hear the difference between the highest-quality digitally modeled guitar amplifiers and effects and their real-world counterparts in the mix. Even the most high-end modeling packages don't cost as much as their real life counterparts, and many also come free in limited versions. So too the wealth of analog synth software, modeled to sound convincingly like the old and newly reissued analog boxes that can run into the many thousands of dollars to collect and connect.

One such collection of synths, the VCV Rack, offers open-source virtual modular synths almost entirely free, with only a few at very modest prices. The standalone virtual rack works without any additional software. Once you’ve created an account and installed it, you can start adding dozens of plug-ins, including various synthesizers, gates, reverbs, compressors, sequencers, keyboards, etc. “It’s pretty transformative stuff,” writes CDM. “You can run virtual modules to synthesize and process sounds, both those emulating real hardware and many that exist only in software.”

The learning curve is plenty steep for those who haven’t handled this perplexing technology outside the box. A series of YouTube tutorials, a few of which you can see here, can get you going in short order. Those already experienced with the real-world stuff will delight in the expanded capabilities of the digital versions, as well as the fidelity with which these plug-ins emulate real equipment—without the need for a roomful of cables, unwieldly racks, and soldiering irons and spare parts for those inevitable bad connections and broken switches and inputs.

You can download the virtual rack here, then follow the instructions to load as many plug-ins as you like. CDM has instructions for the developer version (find the source code here), and a YouTube series called Modular Curiosity demonstrates how to install the rack and use the various plugins (see their first video further up and find the rest here). Modular System Beginner Tutorial is another YouTube guide, with five different videos. See number one above and the rest here. The longer video at the top of the post offers a “first look and noob tutorial.”

VCV Rack is only the latest of many virtual modular synths, including Native Instruments’ Reaktor Blocks and Softube’s Modular. “But these come with a hefty price tag,” notes FACT magazine. “VCV Rack can be downloaded for free on Linux, Mac and Windows platform.” And if you’re wondering how it stacks up against the real-life boxes it emulates, check out the video below.

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Josh Jones is a writer and musician based in Durham, NC. Follow him at @jdmagness.