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Wired for Sound: Making Connections

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We discussed the history and recent resurgence of analog music synthesizers in Part One of this series, and briefly touched on some currently manufactured gear that offers basic facilities for pitch, parameter, and clocking control via control voltage. In this installment, we’ll dig deeper into the what, whys, and how-tos of this electrically based method for interfacing sound modules, and discuss several scenarios that may provide the basis for your own musical experimentation and inspiration.

It Takes Two to Tango

The most basic connection that can be made between two synthesizers is to set them up to play in unison. More than simply doubling the power of a basic synth voicing, unison play allows for the creation of complex timbres—results that may not always be possible with a single synth voice. In actuality, this is similar to how most multi-oscillator synths work, except with those synths, all the components needed for a sound are generated and routed internally—imagine a hearty cassoulet with all the ingredients simmering away to perfection inside a common cooking pot. But much like a tasty meal, a simple accompaniment—in this case an extra synth voice—can lend added dimension to otherwise basic sonic fare.

"The most basic connection that can be made between two synthesizers is to set them up to play in unison."

Two of the most complementary flavors of analog synth come from French manufacturer Arturia, with their MiniBrute and MicroBrute. Both are powerful, single-oscillator monophonic synths with the ability to mix in relative levels of different oscillator wave shapes. This provides the user with a clever way to sculpt complex, harmonically rich wave shapes from a single, shared oscillator. While that’s indeed a neat little trick to get more mileage out of a single tank of gas, so to speak, it’s still no match for the horsepower that can be generated with a true multi-oscillator mono synth like the Minimoog or ARP Odyssey, which have signal paths with three and two discreet VCOs, respectively.

When matched against the prices of vintage Moogs and ARPs, owning both Arturia synths isn’t out of reach for a certain level of enthusiast. And for those lucky enough to own both, a first-class ticket to fat, multi-oscillator bliss awaits! By simply connecting the MiniBrute’s Pitch CV and Gate outputs to the MicroBrute’s Pitch CV and Gate inputs via mono mini-jack cables, notes that are played on the Mini’s keys, or via an external MIDI controller (both synths are serviceable as MIDI to CV convertors), are tracked by the Micro’s sound engine. Route the Micro’s audio output to the Mini’s external audio input and you’ve got a dual-oscillator monster capable of ripping leads and thunderous bass tones. Experiment with various combinations of waveforms or harmonic and inharmonic tunings to create buzzing, metallic tones or sweeping, flange-like effects.

That Syncing Feeling

One of the coolest applications of control voltage is as a tempo-based clocking pulse for a synthesizer’s arpeggiator or step sequencer. Before the advent of MIDI clock sync—a common standard for synchronizing recent drum machines, keyboard workstations, and DAWs—compatible sound-generating devices were set up to play back rhythmic sequences in parallel through the use of periodic voltage triggers. In the early 1980s, Japanese electronics manufacturers, such as Roland and Korg, equipped many of their drum machines with trigger outputs, allowing a would-be one-man band to start pre-programmed sequences on synthesizers with the simple press of a Play button. This may seem primitive in this age of DAWs with unlimited sequencing tracks, but some musicians are discovering that limitations like these can breathe new life into the music-making process.

"You’ll see that the synth sequence now plays in perfect sync with the drum machine’s tempo."

Spawned by the immense popularity of Roland’s classic “X-0-X” boxes of the 1980s, including the TR-909, TR-808, and TB-303, Korg has released the diminutive Volca series of trigger sync-able groove boxes. Volca Beats, an analog drum machine modeled in the style of booming bass thumpers like the TR-808, is particularly well suited for driving musical sequences on either of the previously discussed Arturia synths.

Let’s say you’ve programmed a groovy 4-bar bass line using the MicroBrute’s built-in step sequencer and want a snappy little beat to play in time with your new creation. This is easily achieved by connecting a mono mini-jack cable from the Volca’s Sync Out to the Brute’s Gate In. When Play is initiated on the Volca, a sync trigger is sent on every eighth note of a bar, advancing the Brute’s sequencer in eighth-note increments. Because the MicroBrute’s sequencer advances steps in 16th-note increments, some care will be needed to program rests on every other note to achieve a bass line that does not play at double the Volca’s tempo. You’ll see that the synth sequence now plays in perfect sync with the drum machine’s tempo. Now try slowing down or speeding up the tempo on the Volca—the sequence should stay in perfect time and locked to the beat.

Movin’ & Groovin’

As entertaining as it is to set up a repetitive synth line that playfully putters along to a steady beat, a static sequence can be made far more interesting by creating subtle or dramatic modulations over time. An interesting companion to the MicroBrute is Arturia’s new BeatStep analog sequencer/controller. This low-cost device is a viable alternative to classic CV/gate step sequencers such as the Doepfer MAQ16/3 and the ARP Sequencer. With its CV and Gate outputs and 16 rotary encoders and LED-lit pads, the BeatStep can easily be used as a note sequencer for nearly any voltage-controlled synthesizer. But there’s nothing preventing you from using its CV Out to apply sequenced voltage changes to non-pitch parameters on the MicroBrute and other synths.

Since we’ve already set up a nice beat and sequenced bass line, let’s try creating some further movement to the sound by modulating the Brute’s filter cutoff frequency. In addition to its voltage outputs, the BeatStep happens to be equipped with a MIDI Out, allowing us to send a MIDI clock signal to the Volca’s MIDI In. This will lock the Volca’s tempo to the BeatStep, while simultaneously triggering the bass line sequence on the MicroBrute via the Volca’s voltage Sync Out. This allows us to connect the BeatStep’s CV Out to the Brute’s Filter CV In jack so that now when we apply voltage changes to each of the 16 steps, the filter opens and closes in time with the sequence. It’s also feasible to modulate any of the other parameters on the Brute’s Modulation Matrix, opening up possibilities for intriguing, ever-evolving timbral changes.

Press ‘Play’ on the Volca Beats.
Sequences on both machines now play in perfect sync.

As you can see, control voltage gives a uniquely hands-on window into the ins and outs of synthesis, while providing immediately satisfying results that can be applied to your sound design and music making. In the final installment in the series, we’ll discuss more advanced setups that bridge CV/gate-enabled gear with the brave new future of DAWs and digital audio. Stay tuned.

Click here for Part One of this series.

13 Comments

Previous commenters are correct to note that the setup between 'brute and volca as described in this article will not behave as advertised.   The sequencer on the 'brute runs at half the speed of the volca, not the other way around.   WIth all due respect, I believe the author wrote the article without testing the volca/brute setup, and is now lecturing commenters on the impracticality of troubleshooting individual setups in the comments section in order to sidestep this criticism.  The volca beats is not "particularly well suited for driving musical sequences" on the mini or microbrute.  The two sequencers are only barely compatible, which can be frustrating if one doesn't have another piece of gear or a computer to send clock to both.

Thanks for an interesting article. I have just bought a MiniBrute and I'll probably get a MicroBrute too. Maybe it's a stupid question but what's the difference between your setup and just using midi and route the sound output from both synths to different channels on a mixer? Are there any difference regarding sound? Yes, it's a noob question but I have to ask. Anyway, I own a Volca beats too so I'll try your advice regarding that and MB tonight. Thanks

Hi Dan -

We suggest that in the above article in the third paragraph of "It Takes Two to Tango".  Try it and see for yourself. You may like the results.  Experimentation is what it's all about with these devices.

Please contact us via e-mail if you have additional questions: askbh@bandh.com   

I only have a very old ("Big 80's") Roland TR-505 drum machine.(plan to upgrade very soon!) Problem: When I Connect it via MIDI in to the Microbrute:  Problem 1: instead of just syncing & playing drums the 505 trigers a pulsing F# note that I can't get rid of.   Problem 2: I can no longer transpose the pattern to different Keys unless I hold the the chosen Key down and hold it. If I let go the Microbrut goes bac to the F#.............Help!

Hi Nick -

Troubleshooting your actual set-up is not practical via this platform.  Please contact Arturia directly for support with your specific set-up.

Please contact us via e-mail if you have additional questions:  AskBH@BandH.com

I would contend that addressing Nick's problem here is wildly practical.  I'm having the same problem and any discussion concerning the issue presented here would be of great help to me, and in all likelihood, to others as well.................unless you got something to hide!

Nick, u figure this out?  I'm having the same problem and any help would be most welcome!

nice connectivity ideas there, for micro and mini and volca... good.

but

has anyone tried connecting moog Theremini to micro or mini brutes to see how things go ?

thanks

Hi Kay -

Although we have not tested this hook-up, there is no reason that connecting a Moog Theremini via its analog audio output to the analog input of the "Brutes" should not work. 

Please contact us via e-mail if you have additional questions:  AskBH@BandH.com

Hey, I've been trying different ways to sync the Microbrute and Volca beats for over a month now and I'm not sure what you're saying in that section is accurate. Using your method, the Volca sends an 1/8th note pulse to the Microbrute via sync. This means that you can only get the Microbrute to register a pulse for every other beat of the Volca. The method you suggest of adding rests would only exacerbate the problem and reduce the Microbrute to only playing quarter notes. The only ways I've found to sync them with both playing 16th notes are 1). to send cv out from the Microbrute to the Volca sync in, which leads to the frustrating problem of the Volca pausing it's sequence on every rest or 2). running the LFO out of the Microbrute to Volca sync in which results in being able to get 1/16th notes or even 1/32nd notes from the Microbrute, but unfortunately makes it impossible to use the LFO except very rigidly (1/8th note LFO on 16/th note patterns or 1/16th note LFO on 1/32nd note patterns).

If you know something that I don't, I'd love if you could please include more detail on how you pulled this off. This has been a bit of a let down for me, as I'm very pleased with both synths otherwise.

Hi Lucas -

Troubleshooting your actual set-up is not practical via this platform.  

 It could be that the Volca devices are not CV compatible or that the CV implementation is different.Llooking at the Arturia and Korg forums this issue does not appear as a topic, it could also be that the CV connectors are faulty but that is hard to determine without a tester. Please contact Arturia or Korg tech support: 

https://www.arturia.com/support

http://www.korg.com/us/support/

Please contact us via e-mail if you have additional questions:  AskBH@BandH.com

Sorry but I've never seen anyone say that on an article's comments page, seems a bit snooty to me - definately unhelpful. Both questions asked here on setups are perfectly relevant and any answers would be beneficial to many others. 

Poor show

Hi Eoghan - 

 It could be that the Volca devices are not CV compatible or that the CV implementation is different.Llooking at the Arturia and Korg forums this issue does not appear as a topic, it could also be that the CV connectors are faulty but that is hard to determine without a tester. Please contact Arturia or Korg tech support: 

https://www.arturia.com/support

http://www.korg.com/us/support/

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