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Bat Utility Belt: Building a Briefcase Synth System



You can take it with you…and jam along the way.

I’m a big fan of little synths. They’re easy to play anywhere, from picnics to planes, and each has a unique personality. (I used to keep a Korg Kaossilator in my car to tickle during red lights and traffic jams, but that got a bit too distracting.)

The more synths I gathered, though, the longer it took to set everything up. Cables, mixers, MIDI controllers, batteries, effects… That’s when I found the BlipCase, a compact, hard-shell briefcase developed by Create Digital Music’s Peter Kirn and Blipsonic’s James Grahame. It’s sized to hold four Korg Volcas or six of their own MeeBlip synths. 

At $79.95 plus shipping, the BlipCase is pricey, but when a special offer dropped that to $49.95, I jumped in. That purchase kicked off a wonderful adventure of designing and playing briefcase synthesizer systems. So far, I’ve built three and learned a ton of tricks, which I’ll share below.

Figure 1: Part of the fun of building a briefcase synth system is experimenting with the layout and logic. My first attempt with the BlipCase didn’t work well because the plugs were too long. Switching to right-angle cables and adapters (center top) fixed that.

Case #1: BlipCase — the TARDIS of Sound

Like Dr. Who’s time machine, the BlipCase is somehow bigger inside than out: It holds a surprising amount of gear in a svelte profile. Internal dimensions are 16.4″ × 10″ × 2.75″ (415mm × 255mm × 70mm). Loaded with synths, effects, and batteries, my current setup weighs about 9lbs (4kg). The case comes with 15 foam-covered dividers that slot into grooves around the inner sides (see Figure 1). I used them to pressure-fit a variety of oddly shaped gear, and everything stays snug.

Filling the space optimally was a fascinating puzzle. My first setup had just two synths: a Korg Kaossilator and a MIDIPlus MiniEngine. I often swap the MiniEngine among my cases because it’s so small and weird. This battery-powered General MIDI module has a hundred wheezy sounds and a handful of richer ones, but it includes both USB and 3.5mm MIDI inputs, so you can connect two controllers, set them to different MIDI channels, and play two patches simultaneously.

I ran the MiniEngine’s output into a Boss Tera Echo to gloss up the sound, and then mixed the Tera Echo and Kaossilator through a Rolls MX42 passive mixer. The stereo signal then flowed to an EHX 720 looper, and finally to a Korg Mini Kaoss Pad 2 for global effects. The Kaoss Pad has a built-in recording function to capture everything to a microSD card, and a line/headphone output to share your noise with the world.

Both Korgs run on AA batteries. I powered the two guitar pedals from a USB power pack via a MyVolts Ripcord, which boosts USB’s 5V to a pedal-friendly 9V. A splitter routed the juice to the two pedals.

Figure 2: My current BlipCase rig features an Audiothingies MicroMonsta wavetable synth, Cornfield Electronics ArduTouch (for drones), and an FM radio for up-to-the-minute sound bites. The BlipCase’s detachable lid has enough space under the foam to store the CME XKey controller when traveling. Rotating the Tera Echo 90° made it easier to reach.

BlipCase Reloaded

Although I had two stereo inputs left on the mixer and sometimes filled one with iPhone soft synths, I wanted more dynamic sounds with hands-on control. So, I replaced the 720 looper with an Audiothingies MicroMonsta, a fantastic wavetable synth with six performance knobs and MPE support. Adding a Mode Machines Cerebel USB-to-MIDI converter let me connect a CME XKey, gaining aftertouch and full-size keys. 

The Ripcord powers both the MicroMonsta and the Tera Echo via a splitter and a polarity inverter. I was able to use the USB power pack’s second output to run the Cerebel. (Typically, using dual USB outputs to power different audio gear induces a nasty whine. I suspect the optoisolator in the MIDI circuitry prevented that.)

I like the build quality and compactness of the Rolls mixer (four stereo channels in the size of a business card!), but I got tired of adjusting the knobs. Because it’s a passive mixer, changing any fader throws off the balance of all faders. So, I replaced the Rolls with an even smaller MyVolts MickXer (hidden under the FM radio in Figure 2). The MickXer has five stereo inputs on convenient 3.5mm jacks, as well as output transformers designed to reduce noise. Mostly I noticed it reduced the volume, so I added an Electric Avenues PA2V2 headphone amp to boost the signal on its way to the Mini Kaoss Pad 2.

The silver switch between the PA2V2 and Kaoss Pad is a little gadget I made for the radio. Flipped left, it sends the signal to the mixer. Flipped right, it lets me preview the radio signal on headphones so I don’t land in the middle of a song or commercial. The other sound source is a Cornfield Electronics ArduTouch, a $30 Arduino-powered synth kit that makes lovely drones. I added an inline volume control (the white cord). Velcro anchors the smaller items.

Figure 3: Prototyping my BigBlip case with a cardboard box.

Case #2: BigBlip — More Is More

The BlipCase is good for pedals and small synths, but its latches are flimsy and I had bigger synths I wanted to carry. For my second case, I began by mocking up the layout in a cardboard box (see Figure 3). I used a box the same size as a Harbor Freight Voyager tool case: 18″ × 13″ × 6″ (457mm × 330mm × 152mm). The Voyager lists for just $29.99, and the ubiquitous 20% off coupon drops that to $24. Fully loaded, “BigBlip” weighs 15lbs (7kg). Solid latches and a hefty handle inspire confidence.

The extra depth fit my SwineWAV sample player perfectly. In fact, I had to add a platform to bring my Kaossilator Pro up to playing height. (See Figure 4.)

Figure 4: My 18-inch Harbor Freight Voyager case holds a mass of gear, including a Korg Kaossilator Pro, two effects pedals, three batteries, and a sample-playing pig. A RocketLife LightBox drives 43 LEDs in the rim of the lid under MIDI control. Magnets on top of the Joyo power supply grip a MIDIPlus MiniEngine synth.

BigBlip features three synthesizers: SwineWAV, the Kaossilator Pro, and a guest synth (typically the MiniEngine) that I run through SwineWAV’s auxiliary input. Because the Kaossilator Pro has an aux input too, I don’t need a mixer. SwineWAV’s combined output feeds a DigiTech Obscura delay pedal, which feeds a lovely Neunaber Immerse reverb, which feeds the Kaossilator. The signal then mixes with the Kaossilator sounds and goes to the Kaossilator’s line and headphone outputs.

MIDI is streamlined, too. An Arturia KeyStep controls the MiniEngine and a RocketLife LightBox through a custom splitter under the reverb pedal. Each keypress triggers an animation on a strip of addressable LEDs lining the lid, with Velocity controlling brightness. (Addressable means any LED can be any color at any time.) The Kaossilator’s MIDI Out feeds the KeyStep, which I set to external sync. That lets me create arpeggios on the keyboard that are synced to the Kaossilator’s tempo. 

Synth and effect power comes from two USB battery packs (with another Ripcord for the Kaossilator) and a Joyo JP-05 9V power bank. The LightBox has an internal battery.

Figure 5: BinderBlip lives inside a 3-ring binder. A Keith McMillen QuNexus keyboard controls the MIDIPlus MiniEngine. A Gechologic Gecho V2 Loopsynth adds spacey effects and recording. The red knob is an additional modulation control. The glowing crystal responds to the QuNexus’s CV and gate outputs.

Case #3: BinderBlip — A Three-Ring Circus of Sound

The night before the 2020 NAMM show, I decided I wanted a synth system for the flight to Anaheim, so I built a tiny rig inside a three-ring binder. First, I drilled out the binder clips. Then I Velcroed in a KMI QuNexus, Gecho Loopsynth, and the MiniEngine. (I learned a little bit of Velcro goes a long way.) Because I find the QuNexus pressure and positional sensors hard to control, I attached a potentiometer to its CV input. Depending on the preset, the pot controls modulation (CC1) or filter cutoff. Wiring details are in the QuNexus manual.

For extra bling, I embedded two color-changing LEDs in a chunk of acrylic ice and attached a 3.5mm TRS plug. Connecting that to the CV/gate output produces a variety of colors that flash and evolve as I play. The Loopsynth functions as an effects processor for the MiniEngine, with trippy granular algorithms ported from Mutable Instruments Clouds. Add a microSD card, and it can record everything you play as well.

Good to Go

Building and playing your own portable synth system is more fun than a briefcase of monkeys. I’m already plotting my fourth rig. I even considered using identical cases with different contents so I could grab one and be surprised when I pop open the lid. Last November, synthmeister Mark Vail and I performed a briefcase duet at Sacramento Audio Waffle. While other artists took 25 minutes to set up, we simply flipped open our cases, plugged into the PA, and started playing. Here’s a board recording of our improvised jam, with photos of Mark’s setup. Notice how he packed in even more gear by mounting it in the lid of his Pelican case. Happy travels!

What’s in Your Utility Belt?

The Bat Utility Belt series covers surprisingly useful synth gadgets that cost less than $100. Got a tip? Post it on Facebook, Instagram, or Twitter and tag your nomination #BatUtilityBelt. You can also reach me through If I feature your submission in an upcoming column, you’ll win a free subscription to Synth and Software. Oh, wait—that’s free already. Blip!

Websites: BlipCase | Harbor Freight Voyager

Price: $29.99 & up

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