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Korg R3 Synth/Vocoder

Synthesizer & Vocoder Keyboard By Paul Nagle
Published September 2007

Korg's new synth may be small, but there's much more to it than meets the eye...

Korg R3 Synth/VocoderKorg's Radias was a curious synth, pairing a small, neat module with an optional, but disproportionately large, keyboard and tilting rack. I fell in love with the Radias sound instantly and longed for a smaller, more portable version of its keyboard, or perhaps an MS2000-style complete package. Hearing of the R3, I crossed my fingers that Korg were thinking along the same lines. As details percolated through, I realised that the R3 was a more modest creature; it does indeed borrow from the Radias, but with a keen eye on budget. The lower price is refected in a pruning of knobs, polyphony and multitimbrality, so does it retain enough Radias sparkle to satisfy?

Rather Radical Revamp

Externally, the R3 looks closer to the Microkorg synth than the Radias. Happily the keys are full-sized, protruding slightly over a rounded plastic body. I found the keyboard action to be acceptable — but there's still no aftertouch!

If the keys have grown up, the size of both the mod wheel and pitch-bender suggests that they originated in Hobbiton; the mod wheel in particular has a very short travel, ideal for hobbit fingers. I'm not complaining, though; I prefer my gear as petite as possible and three octaves is a serviceable length, made cheerier by octave transposition buttons that change colour according to the amount of transposition, passing through green and orange and finally arriving at red to denote that the maximum three octaves up or down has been reached.

For its power needs, the R3 is accompanied by yet another variation on Korg's plastic carpet-carbuncles. Given that we are doomed to suffer these things eternally squatting on our four-ways, why on earth can't they settle on just one type? Sadly there's no battery option either, which, given the R3's weight of less than 3kg, is a blow to potential portable performers.

Everything else in the connection department is as you would expect; there are the requisite number of MIDI sockets (three), a USB port, stereo audio outputs and assignable footpedal connectors. The R3 has two inputs for the processing of external audio, while on the front panel there's an additional XLR socket for the supplied gooseneck microphone. Slot in the mic and you can bend it round when you fancy a bit of vocalising and thrust it to one side when you don't. It's neat and effective and will surely encourage lots of gratuitous vocoding, plus all kinds of malarkey involving the onboard filters and effects.

Sounds Like...

Initial exploration is childishly simple. A large LED-encircled rotary encoder is used to select a patch category. There are 16 available (designated A-P) and they include Pad/Strings, Lead, Bass, and so on. On first glance you might miss the final two categories, as they are labelled in a very dull red text, but they contain splendid vocoder and formant-motion patches, so you should try not to overlook them for long.

I'm not keen on grouping my creations under hard-coded category names (you can define your own in the Radias) but fortunately there's nothing to stop you storing, say, a vocoder patch in the bank labelled 'Perc/Hit' should you wish. Each category contains eight patches — making just 128 in total, which feels a bit stingy.

As shipped, the R3 contains a high proportion of bright, clear patches, and to some this will maintain the perception that Korg's synthesis is lacking in warmth or fullness. I've even read comments from Radias users who are convinced the synth is only capable of 'the glossy Korg sheen' — yet with thoughtful programming it's not difficult to duplicate the muddy slush of other instruments. There are a fair number of fizzy, trance-type examples ready to go, but there's also a decent collection of vintage-style basses, leads and polysynths. Throw in a smattering of bells, electric pianos and sound effects and the factory sounds give enough of an impression of what the R3 can deliver. As is often the case, it'll probably be the delay-swamped arpeggios and sequencer-type outings such as 'K-1 Phospho' that will instantly grab attention.

Missing In Action

The R3 isn't quite half a Radias, and not simply because of its eight notes of polyphony. For a start, it lacks the drum PCMs and the ability to construct drum kits. It also takes a different approach to digital waveforms. Although each synth has a total of 64 digital waves, the R3's consist wholly of DWGS (Digital Waveform Generation System) waveforms, created by harmonic additive synthesis. The Radias, on the other hand, offers a selection of PCM waveforms, including some particularly good electric pianos, choirs and electric and acoustic basses. So the R3 won't cover all the sonic real-estate that the Radias can.

Since the R3 has just two parts, a stereo pair of outputs is sufficient. More of a loss is the reduction in modulation sequences, from the Radias's three to just one per timbre. There are minor changes too, of varying importance. You lose the ability to set the different portamento or decay/release envelope curves that I find invaluable on the Radias. The R3 has no step sequencer, no alternate scales or user scale function. There is no internal bus and no envelope follower — the latter so useful as a control source or note trigger. But none of these omissions have a major impact on the R3: I think Korg have chosen well.

Deeper In

There are just four knobs with which to edit your creations or make mid-performance tweaks. This minimal knobbage is supplemented by five separate displays, each backlit in a moody red. I was none too enamoured of either the colour or quality of these poky little screens. Although a contrast knob on the rear panel permits adjustment according to playing position, I still found the viewing angle uncomfortably narrow. If, as I do, you alternate between sitting and standing during performance, you may find your fingers wearing a regular path to that diminuitive contrast knob. If you don't move about too much or rarely glance at displays, you may be OK, but it's definitely something to check out, should the R3 be on your 'watch list'.

Navigation through the various edit pages is via a single dial, with each page containing up to four options. Many of these pages show the parameter name initially in the display, then when you turn the knob its value is revealed. In some instances this is irritating; for example, when setting up modulation via the virtual patch cords, the main display might say 'Patch 6' while the first of the sub-displays says 'Source 6' and the next 'Dest 6'. You must turn the knob before seeing what the sources/destinations actually are. I'm confident some bright spark at Korg could devise a better method of labelling than this.

Fortunately the knobs have green LED sleeves that graphically illustrate the underlying values. These, combined with the 'original value' LED, should be adequate to undo things speedily when a tweak doesn't work out. There's an alternate knob mode, 'Catch', in which the parameters begin to change only when you turn the knob past the stored value; ideal for seamless changes, as with non-programmable synths of yore.

Multiple Modelling Technology

Having explored the menu system, I saw how similar the R3 and the Radias are architecturally. Therefore, rather than wastefully retread old ground here, I'll refer you to the Radias review from the April 2006 edition of SOS. That, plus the 'Missing In Action' box above, should give you a feel for the main differences between the two. I'll mention any significant others as I go along.

Essentially, the R3 is a bi-timbral synth with a maximum of eight notes of polyphony. This puts it in the category 'fun, portable keyboard' rather than 'multitimbral powerhouse' — although it can function perfectly well as a two-channel multitimbral synth. Even a three-octave keyboard can make surprisingly good use of splits, and layering two R3 timbres can produce rich, lush results. As each timbre maintains individual knob assignments, you can select key controls for instant access, twice over.

All of the R3's features can be operated using the rather minimal set of controls on the front panel.All of the R3's features can be operated using the rather minimal set of controls on the front panel.The R3 is blessed with Korg's Multiple Modelling Technology (MMT), so don't expect to only hear analogue-type sounds. Each timbre features a twin oscillator and filter structure with a versatile drive/waveshaping section, two LFOs and three envelopes. Getting a final spit-and-polish courtesy of two insert effects and an EQ, a master effect section then processes both timbres equally. By anyone's standards, this is a varied box of sonic screwdrivers, especially when you factor in virtual patching, modulation sequencers, a vocoder and an arpeggiator. If you can't get the job done with the R3, it won't be for lack of tools.

Of the two oscillators, oscillator one is the more complex, offering modelled analogue waveforms, formant (vocal-type) waves, noise, 64 digital waveforms and the audio inputs as sound sources. This oscillator is further spiced up by a selection of modulation types, each applicable to the wave selected. There's pulse-width modulation, cross modulation, unison and also VPM (the latter a simple but effective form of FM). If, by contrast, oscillator two seems basic, we shouldn't complain too much. It still features the usual analogue waveforms, plus oscillator sync and ring modulation. And at the mixer stage, a separate noise source is always on tap to instantly satisfy any urge to whoosh or swoosh.

It may surprise you to discover that chunky bass and full-bodied solo patches can be programmed using just a single oscillator. A cunning way of adding extra fatness involves the Drive/Waveshaper, whose charms include hard clipping, drive, several sub-oscillators and an electromagnetic pickup simulator. Drive/Waveshaper can be positioned before or after the filter and is responsible for some of the R3's rougher, more cutting tones. When used subtly, it can impart a surprisingly organic, warm character to sounds.

The filters are smooth and creamy, with only high resonance settings threatening to betray their digital nature. Filter one features a continuously variable sweep through low-pass four-pole, then low-pass two-pole mode, followed by high-pass, band-pass and, finally, 'thru'. Although the second filter doesn't accommodate these smooth transitions, it does boast a comb filter along with its low-, high- and band-pass personae. You can use one filter alone or configure the two in series, parallel or individual modes — the last of which meaning that each oscillator is processed by a separate filter.

Finally, the two LFOs and three envelopes are vital inputs to Korg's virtual patching system. This is a means of connecting a small selection of modulation sources to a similarly small selection of destinations. Virtual patching may be underwhelming for those of us who cut our teeth on Access, Alesis or Oberheim synths, yet it does add some programming depth.

Closer To The Edit

Korg R3 Synth/VocoderThe R3's software Editor provides a clear map of all the different functions. Bundled into the package is a CD containing additional documentation, editing software and a USB driver. The driver acts as a convenient MIDI interface for your PC or Mac, and once this and the Editor are installed, all worries about the R3's interface could dissipate forever. The Editor may be rendered in a rather drab shade of brown but at least it lays out all the R3's entrails before your eager eyes. Using it, you will quickly gain a deeper understanding of what lurks inside; within minutes you should be hurtling around, tweaking wildly or performing minor surgery on your formant data. Or perhaps remapping every parameter to a different MIDI Continuous Controller, if so inclined. Incidentally, if thoughts of mice make you want to stand on a chair and scream, the R3's comprehensive MIDI spec offers the opportunity to draft in an external knob or slider box, giving direct hardware access to every important parameter. Yay!

Vocally Yours

Vocoding is clearly an important role for the R3, so it's good to be able to report that this 16-band implementation is both clear and articulate. Whether for robotic voice effects or more off-the-wall, experimental choirscapes, the vocoder is just as willing to work with your voice or external samples. Your source may even be derived from 'Formant Motion' — a function transported intact from the Radias. Using this you can store 16 'formants' (the results of the vocoder's input analysis), each of up to 7.5 seconds. These formants can then be used, with no further audio input, to drive the vocoder.

Having used formant motion in my Radias for the last year, I find it slightly limiting that you can't alter the tempo of formants post-capture. Also, I'd love to be able to step through the transients by playing notes, V-Synth-style. As it is, you can either loop your formants or you can retrigger them from the start, on each note. That said, it's a worthwhile feature to have, as demonstrated by several factory patches.


We've seen that each timbre has EQ plus two insert effects, and that their combined output is processed via a single master effect. In a sense, this works better on the R3 than on the Radias, because on the Radias it's much less likely you'll find a master effect suitable for all four timbres at once. Remember that the master effect works like a blanket; it lacks individual send levels for each part. On a solo synth this is not such an issue — in fact it's jolly useful to have a global reverb or delay that is controllable by a single knob

There are 30 different effects on offer ranging from cabinet simulators, limiters and gates to Korg's marvellous grain shifter — and more. With a decent enough reverb and a generous assortment of delays, Korg have once again turned up trumps in the effects department. My only gripe is the inability to control effects parameters using either the virtual patching system or the modulation sequencer.

Arpeggiator & Modulation Sequences

The R3's arpeggiator is able to drive either timbre individually, or both at once. So, for example, you can generate a bass loop with one hand while playing chords with the other timbre. An arpeggio may be up to eight steps in length (compared with 32 on the Radias) and during editing the patch-select buttons are employed to toggle activation of each step, thus enabling the creation of more varied, broken-up patterns.

The R3's rear panel houses all of the synth's connections apart from an XLR socket for the vocoder's microphone, which is situated on the front panel.The R3's rear panel houses all of the synth's connections apart from an XLR socket for the vocoder's microphone, which is situated on the front panel.The usual directions (up, down, random and so on) are provided, along with a swing option, which progressively shifts the even-numbered beats for further groove variation. As with all the best arpeggiators, there are dedicated on/off and latch controls on the front panel. Admittedly, there aren't a gazillion different modes or options, but I'm personally content with the R3 in this area — especially when you add modulation sequences to the rhythmic equation.

Seen on earlier Korg synths and the Electribe series, modulation sequences are a means to specify knob widdles to be played back automatically, just like an old-style analogue sequencer. Each timbre has one modulation sequence (the Radias has three) of up to 16 steps and is designed to control an individual R3 parameter or one of the performance knobs you've assigned. Actually, some parameters are frustratingly out of bounds; for example, any that are effects-related. You only learn which parameters cannot be modulation sequenced when you try to record them and find that nothing happens.

The easiest way to create a modulation sequence is to activate the Mod Sequence function, then hit the adjacent Record button. Then, while holding down notes on the keyboard, turn the knob of your choice. That's it! The ring of 16 LEDs that indicates the category in play mode is used to good effect here: during recording, a light chases around this ring to indicate the Mod Sequence's progression. For greater precision, you can edit each step's value by turning a knob acting as 'step number', while a second knob is used to adjust the value. The resulting modulation sequence can be smoothed or stepped and can run in a choice of directions and clock divisions.

Seasoned sequencer and arpeggiator users will feel duty-bound to add clock-sync'd gate, delay and LFO effects, before generating complex polyrhythms by combining arpeggios and modulation sequences of differing lengths. Warning: this can be dangerously addictive.


The R3 is a portable plastic synth capable of some sweet, and even heavyweight, tones. Pinning its colours to the mast, its label cries 'Synthesizer/Vocoder' — and the vocoder alone may be enough to justify purchase. Certainly there's ample choice for voice-based effects once you've spent time mastering it. Sticking my neck out, I'd say it's more versatile than my old Korg VC10 vocoder — and don't forget there's a cracking synth thrown in too!

Having just four knobs means the R3 is never going to be as fast and immediate as some of its competitors and, as you've probably gathered, I wasn't too impressed by those gloomy red displays. However, anyone of a computery disposition will find that the supplied Editor software quickly eases any editing pains, while also being the perfect tool to assemble libraries of your favourite patches, ready to shunt around those precious 128 memory slots.

In a year of use, I have grown ever more fond of my Radias and can imagine the R3 appealing to any who desire those lush, juicy tones in a more affordable, compact and convenient form. Capable of filling many different roles, the R3 is a little synth with a big heart. 


  • Excellent onboard vocoder with free gooseneck mic thrown in.
  • Clear, bright sounds and quality effects.
  • Effective combination of arpeggiator and Modulation Sequencer.
  • Editor software and USB MIDI included.


  • Displays could be clearer.
  • Keyboard lacks aftertouch.
  • Not quite half a Radias.


The R3 is a light, readily-transportable keyboard, loaded with classy sounds and more options than its impassive exterior might imply. As a vocoder, solo synth or simply something to noodle with on a rainy day, the R3 should provide hours of pleasure.


£552 including VAT.

Korg UK Brochure Line +44 (0)1908 857150.

+44 (0)1908 857199.