The Korg iMS-20 on iPad: Digital has never seemed so analogue

When you launch the Korg iMS20, the new iPad app developed for Korg by Detune Ltd, the splash screen shows a picture of the iconic Korg MS-20 analogue synthesiser patched to an SQ-10 analogue sequencer with yellow patchleads, and next to the picture are the words 'Korg iMS-20 Analogue Synthesiser'.

Now, that's enough to make a die-hard fan of analogue synths (such as the Korg Monotron ribbon synthesiser) start to get very nervous. I'm looking at a piece of digital multitouch hardware less than a centimetre thick telling me it's an analogue synthesiser... and I'm worried. I'm about to spend an evening with the iMS-20 on the Apple iPad and, as an ex-MS-20 user, my expectations are perhaps somewhat high.

The interface

In all honesty, I nearly forgave Korg as the interface screen appeared. It really is a complete MS-20 interface, with every control knob lovingly recreated on its black and white panel (plus a couple of extra discreet little switches). All  the patch sockets are exactly the same, and even the single mod wheel and funny little trigger button are exactly as I remember them. OK, Korg, you've got my attention.

Although there's a keyboard built into the app, with a choice of two zoom sizes (the historically accurate 3-octave one and a less fiddly, variable width 2-octave one), I found that I could plug my Novation X-Station keyboard straight into the USB port on Apple's optional Camera Connection Kit for iPad and get MIDI control. Not only that but the iMS-20's audio came out through the X-Station. Bonus! Any class-compliant MIDI interface or keyboard should work, provided it has mains power. I guess that since the Novation has audio interface and MIDI capabilities, it does both jobs at once. You can see how I achieved this set-up in the video at the bottom of the page.

The controls

Before I started to play with the controls, I wanted to get a basic feel for the sound and this is where the digital side of synthesis scores hugely over the original. Touching the patch name in the top right corner brings up a full-screen list of patch memories. There are 50-odd 'templates' in the list, and you can preview them by touching them without having to leave the list page. On the left are sub-categories of template - Synth and Drum (yes, drum) sounds - and recently created, updated and loaded sound. I picked one and returned to the control panel.

My first impressions are good. The controls operate exactly like rotary controls - you touch a control and move your finger in a circle to alter the parameter. Yellow text tells you the value you've produced as you turn, but it appears right under your finger. You can slide your finger away from the control and the circular motion still works - effectively you're making a giant rotary control with your finger, and now you can read the text. However, if your finger momentarily loses contact, you might have inadvertently strayed on top of a different control and suddenly you're turning the wrong control knob. This takes a bit of getting used to, but the big advantage is that the further 'out' from the control you go, the finer the control you get. Those tiny little detunes which made the original MS-20 so fat are perfectly achievable in the iMS.

My main gripe with rotary touch controls is that it's impossible to alter more than two of them at once - the brain just can't draw more than two circles at the same time. Luckily, Korg have thought about this and in the Global page you can change the action required to turn a control from Rotary to Linear (i.e. up and down movements) and reposition the text. There are also two X/Y touch controllers accessed by touching the 'Kaoss Pad' controller button. These are slightly odd in terms of what you can control with them, but I suspect they might be really handy in a pinch. They override the parameters assigned to them, but only while your fingers are on them which is great for impromptu slides, squeals and filter sweeps.

The sound

So what does it sound like then? Good, actually. The circuits behave pretty much how I remember them with precise envelopes and single triggering monophonic keyboard just as expressive as the original and oscillators which are maybe even slightly better behaved. Filters, both HPF and LPF are nice and not perhaps as frighteningly unpredictable as their analogue ancestor, but they self-oscillate as they should and seriously distort each other in ways that make me very happy indeed. I dug out my ancient folder of MS-20 patches and started drawing in yellow patch leads and tweaking controls. Yes, it's all there and pretty damn close to the real thing. But there's more - a lot more.

Remember that SQ-10 sequencer in the splash screen? It's also just visible on the main control panel at the top and all you have to do is drag the screen downwards for the three banks of 16 rotary voltage controls to become available. What's slightly less apparent is that you actually have no less than seven sequencer 'tracks' to play with, all of them simultaneously playing. Six tracks are accessed with the 'Drums' button at the top, revealing a 6x16 button matrix. Pressing a button switches a particular drum sound on or off on each step, like the TR808/909/606 drum machines.

The amazing thing here is that each track is controlling a full instance of the MS-20 synth and, since each row of control voltage knobs can control a parameter of the synth, there's nothing to stop you playing a sequenced synth or bass part rather than a fixed pitch drum sound. It's hard to believe all that power is hidden inside this slim piece of Apple technology, but delving deeper reveals the 7-track, 16-step sequencer has 16 pattern memories, and the patterns can be chained into a song of up to 256 patterns in length. Each track can have an independent number of steps for syncopated or polyrhythmic sequences. Sequences can loop forwards, backwards, bi-directionally, by odd steps followed by even ones... it's immense.

The verdict

So, overall scores? Ten out of ten for the recreation of a timeless analogue classic. It's as close as I think it's possible to get, and just as much fun as its parent. In some ways though, there's an inherent problem in the design. It's great for someone like me to see that well-loved black and white panel again, however, it was never the friendliest of beasts to get your head around, nor the easiest to read.

OK, the Zoom MS-20 button fills the iPad screen with just the control knobs, losing the keyboard, wheel and patch panel to make the text more legible. Dare I say it, alternative skins with colour-coded controls might make it easier for new users to figure out what's happening. But that really is all I can find to improve the iMS-20. It sounds amazing and makes you just want to plug things in and twiddle the controls to see what happens. This is more than just a synth - it's a full composition tool and, you know something? It's worth buying an iPad just to own it.

For more information on Korg synthesisers and controllers or Apple hardware, give us a call on 03332 409 306 or email audio@Jigsaw24.com. You can also drop us a comment in the box below if you've used the iMS-20 synth - we'd love to hear your thoughts.

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