Your next modular input might just be an iPad or iPhone headphone jack.

Control voltage inputs, once associated only with racks of modular synths, are now showing up on all kinds of synthesizers and keyboards. Arturia’s MicroBrute and MiniBrute are two very lovely, very affordable examples, priced less than most entry-level digital synths were just a few short years ago.

And since all you need is a sound signal to modulate those inputs, even a phone or tablet app will do the trick. Developer Justus Kandzi, who came to one of our music app meet ups here in Berlin, has built some brilliant, compact apps for the job. Brute LFO is the cost of a cable — just five bucks; Trigger Box is free.

Plug them in, and you can use touch to create elaborate sound sculpting shapes (Brute LFO), or spawn Euclidean sequencer rhythms (Trigger Box). These apps don’t replace anything already on hardware; they add to what’s already there, and in the case of Trigger Box, can use an interface and design paradigm that makes sense on a display but might not on physical hardware.

Here’s a great example pairing the iPhone app with Arturia’s keyboard:

A second film shows analog voltage measurements.

Of course, part of what’s nice is that this sort of tool is agnostic. A new Arturia? A vintage KORG? Yes – both. Here’s a PolySix:

And then there are sillier possibilities, like an accelerometer shaker (upcoming):

Brute LFO may have fake knobs on it, begging the question of why you wouldn’t want to add these controls to the synth itself. But on the other hand, that’s part of what keeps the Arturia keyboards portable and affordable, and Brute LFO is a powerful, flexible tool in combination.

And yes, I’m aware I missed this earlier this summer – but now, with autumn coming for some of us, it seems the perfect time to wrangle some useful tools.

The old “MIDI versus analog” debate seems long forgotten. Now, both MIDI and control voltage are becoming no-brainers on new hardware. They each solve a particular problem conveniently; they each work with a massive variety of hardware – they’re about the two easiest tools hardware makers could implement. And they each coexist as well with vintage hardware as new, affordable hardware, DIY creations, and the latest computers and Apple gizmos.

Brute LFO on the App Store

Trigger Box on the App Store

More Euclidean rhythmic goodness:
Polyrhythmus is an Insanely-Great, Free Generator of Rhythms, Arpeggios