Korg Microkorg

Modelled Analogue Synthesizer & Vocoder

Published in SOS January 2003
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Reviews : Keyboard

Photos: Mark Ewing
Korg's Electribe grooveboxes presented their analogue-modelling technology in an affordable, dance-friendly format and were a smash success. Now, using the MS2000 virtual analogue synth as a starting point, they're hoping for similar budget triumph with the fun-sized Microkorg...


Paul Ward

The latest product to feature Korg's analogue synth-modelling technology, the diminutive Microkorg synth shares many of the features of the company's well-respected MS2000/MS2000R. It arrives in a cute package, capable of running on six AA batteries, with a mini-keyboard and more synthesis features than any machine its size should have any right to boast. Apart from its four-voice modelled-analogue synth, Korg have endowed the Micro with a highly capable vocoder (also four-voice — see the box later in this article), a programmable arpeggiator, virtual patching system and a very healthy MIDI spec.

Something about the style and colour of the Microkorg reminds me of such mid-'80s Korg classics as the Poly 800 and DW8000. It took me a while to also realise that the control knobs bear more than a passing resemblance to those on my Minimoog — in fact, apart from the position marker on the knob, they are nearly identical! Spooky...

A quick glance around the back reveals a 3.5mm headphone output, a pair of 3.5mm left/right line outputs, two sets of audio inputs, a trio of MIDI connectors (In, Out and Thru), a power switch and the connector for that justifiably hated external power supply! However, there are no sockets for pedals or footswitches.

First Impressions

The Micro's keyboard is a 37-key C-C type, incorporating velocity response, but lacking aftertouch sensitivity, and it's composed of mini-keys, which is a little strange to my way of thinking. Serious players will be dismayed by it, and yet it's not quite aimed at non-players either, as they would surely have been quite happy with even fewer notes?

Korg Microkorg £399
pros
Powerful, convincing analogue synthesis.
Compact design.
Simple, effective real-time editing controls.
Flexible vocoder with external audio inputs.
Dedicated microphone included.
Optional battery operation.
Good MIDI controller capabilities.
cons
Limited polyphony.
Mini-keyboard not suited to 'serious' playing.
Involved editing can be a pain.
Small, sometimes cryptic LED display.
External power supply.
summary
The Microkorg sounds great, and may suit some live applications, but others are going to find fault with the mini-keyboard, four-note polyphony and fiddly in-depth editing regime. It's good as a MIDI controller, though, and the battery operation allows you to use it on the move. Whether you like it will therefore depend on your particular needs, but it's definitely worth an audition.

There are 128 program memories, any of which are available for overwriting with your own creations, though the factory presets can be recalled at any time in future if required. The programs are arranged in two 'sides' of eight banks of eight programs. The two 'sides' are selected by a dedicated button, and you access the eight banks via a large knob which clicks around a questionable series of genre titles, such as Trance, Electro and Hip-Hop/Vintage. I'm not convinced as to how useful these titles are, to be honest — it all smacks a bit of home-keyboard territory, and anyway, once you've edited a few of the programs, the chances are the descriptions will no longer be valid. Maybe simply numbering the banks from one to eight might have been preferable; this is, after all, how the Microkorg's simple three-digit LED denotes the bank and program numbers... Programs within the current side/bank are accessed by eight numbered buttons just below, and using these buttons in conjunction with the Shift key allows you to access various housekeeping functions. Most of the Microkorg's buttons are illuminated, which is useful, though I doubt the panel legending would be visible on a darkened stage.

Editing & Synth Architecture

I was concerned on first looking at the Microkorg that I was in for hard time programming the machine, given its relative paucity of controls (see the 'User Interface' box towards the end of this article). To a great extent, I'm afraid my fears were realised. If you are heavily into sound programming, I'd strongly suggest you find a suitable computer editor, or get used to 'ship-in-a-bottle'-style twiddling. Also, thanks to the absence of any other form of screen, Korg have had to resort to cryptic LED messages to display some of the parameter values, and it will take time to become familiar with these.

The Microkorg's basic synthesis architecture is fairly normal for anyone familiar with analogue synthesis, and is very similar to that of Korg's MS2000. The smallest building-block of sound is referred to as a 'Timbre', this being the result of a pair of oscillators (plus a noise generator), a multi-mode filter, amp, envelope generators, LFOs and virtual patching blocks (of which more later). Either of the two possible Timbres may be solo'ed during editing and Timbres can be swapped and copied to aid programming. The Timbres are then presented to the input of the effects, which consist of a single modulation effect, a delay and an EQ processor, before the result arrives at the stereo output. Although the Microkorg is bi-timbral in the sense of being capable of producing two synth sounds at once, it is not possible to address the timbres separately over two different MIDI channels — so you couldn't have a sequence and bass line playing different notes at the same time.

At best, the Microkorg is four-voice polyphonic, and the voices are allocated depending on the voice assignment set for each of the two Timbres. If both Timbres are layered together in Poly mode, the synth will become two-note polyphonic. Mono mode is provided to emulate a true monophonic synth, whilst Unison mode layers all four Voices together with a variable degree of Unison Detune to create a richer, fatter sound.

Oscillator pitch is variable over a range of four octaves, with fine-tuning to one-cent steps. The range of effect of the bend lever from -12 to +12 semitones is adjustable, as is the vibrato depth imparted by the mod wheel. Portamento is available, and portamento time is adjustable, but unfortunately there is no option to specify a fixed portamento rate, making longer portamento times sluggish over short key spans, and rendering old Minimoog portamento lead sounds a tad difficult to emulate convincingly.

Of the two oscillators, Osc1 has the lion's share of the waveforms, with a complement of saw, square, triangle, sine, vox, DWGS (of which more in a moment) and noise types. Alternatively, Osc1 can be replaced altogether by the signal arriving at either of the two audio inputs. Oscillator sync and ring modulation are also available and both may be utilised simultaneously. A pair of controllers assigned to Osc1 allow for a range of basic sound-shaping features to be applied to the raw waveform — these vary with the selected waveform, but include pulse-width, cross-modulation (with Osc2), and the introduction of higher harmonics into the waveform. These are sophisticated wave-bending features and very welcome in such an unassuming synth.

The 64 DWGS (Digital Waveform Generator System) waves hark back to the days of the DW8000. These waveforms are the result of additive harmonic synthesis, and usually sound glassy, hard-edged and 'digital'. They allow the creation of all kinds of metallic, bell and electric piano sounds which are normally outside the scope of a purely analogue synth.

Osc2 is an rather simpler affair, capable of generating only saw, square and triangle waveforms. Independent tuning is available to generate detuning or musical intervals in semitone steps. Once both oscillators reach the mixer they are joined by a noise generator, independent of Osc1. Finally, each of the three signals may be individually attenuated before passing to the filter.

The Microkorg is supplied with its own mic for vocoding purposes, and although it's a little physically flimsy, it makes a fine job of it.

The filter is again surprisingly advanced, with options for a full-blooded 24dB-per-octave low-pass filter, in addition to 12dB-per-octave low-, high- and band-pass variants. In addition to its basic cutoff and resonance controls, the filter has its own dedicated ADSR envelope generator and key-tracking, both with variable positive or negative depth controls, and it will happily go into self-oscillation when the resonance control is turned up sufficiently high. Both the filter and amp envelope generators are of the ADSR type, with the option to force the envelope to reset to zero amplitude each time a new note is played, or to pick up from the release level of the previously played note.

In the amplifier section, there's a simple level control to determine the overall patch level, although this acts as a balance between Timbre 1 and 2 when a layered patch is created. A pan pot determines left/right balance and variable key-tracking will increase or decrease volume level across the keyboard. The amp section also offers a useful distortion processor, a simple on/off control which relies on the levels set in the mixer to determine just how much distortion is applied.

The Microkorg's two LFOs are near-identical, with the exception that LFO2 offers an triangle wave rather than LFO1's sine wave, and also contains an unusual 'positive-only' square wave in place of LFO1's more usual positive/negative square wave. A positive-only wave can be useful, for example, where you might want a pitch warble to flip between the played pitch and a higher interval, whereas the more usual positive and negative wave would warble the pitch at above and below the played pitch. There's no positive-only equivalent for the sine or triangle wave, though, which could have been useful in simulating guitar vibrato. Key sync of the LFO is possible, as is tempo sync, so modulation can be synchronised to either the internal arpeggiator tempo, or an external MIDI Clock source at a variety of cycle values, from four beats per one cycle to one beat per two cycles.

As mentioned earlier, four so-called virtual patch routings are available, and it is here where much of the Microkorg's strength lies. Each Patch allows the selection of a modulation source and its application to a modulation destination, with a variable positive/negative intensity. Modulation sources include both LFOs, both envelope generators, velocity, keyboard tracking, and the mod and pitch wheels. Destinations include pitch, Osc2 tuning, noise level, filter cutoff, amplitude, pan and LFO2 frequency. As you might well imagine, this gives you scope for a whole world of modulatory mayhem, and some of the factory presets show what can be achieved with a little thought and application.

  The Vocoder  
  The Microkorg's vocoder retains the synth's four-voice polyphony, utilising an oscillator and a noise generator per voice. As with all vocoders, two input signals are used. The so-called Modulator signal (often, but not necessarily, a vocal input from a mic input) is analysed by envelope followers and split into 16 frequency bands, the relative level of which are used to impart the incoming signal's frequency spectrum on the other signal, the so-called Carrier (often a synth pad or tone, although again, this doesn't have to be the case), by means of 16 corresponding band-pass filters.

The cutoff points of the filters can be shifted up or down to raise or lower the overall frequency response of the vocoder effect (carefully set, this could allow you to simulate a male vocal from a female voice, or vice versa), and resonance may be added to colour the sound. The current vocoder frequency response can be 'frozen' at any time by pressing the Formant Hold button. For editing purposes, the filters are arranged as eight pairs, or 'channels' and, at the output of the carrier signal, each channel has an individual level and pan control. The Envelope follower sensitivity is adjustable, as are gate threshold and gate attack time. Controls are provided to determine how the modulator signal's high-frequency content will be treated, either passing through unhindered, or being heard only when a note is being keyed. The volume of the passed high frequencies can be altered for subtlety or overly sibilant effects, and experimenting with this can aid intelligibility if the modulator is a voice.

The vocoder modulation options are not as varied as they are for a synth patch, but this is to be expected. The carrier filters may be modulated by the amp envelope, either of the LFOs, velocity, keyboard tracking, the pitch-bend wheel, or mod wheel. The provision of individual volume and pan controls for each of the eight output channels is generous, and allows the creation of lush stereo spreads.

The supplied microphone slots into a socket on the rear of the case and has a flying lead that plugs into Audio In 1 via the 'condenser' mic mini-jack socket. A second 'dynamic' standard jack socket is also available to which line sources may also be connected, and there's a mic/line selector switch, which is a nice touch. Audio input 2, on the other hand, accepts line-level signals only. Both audio inputs have a small trim control knob by the socket (labelled 'Volume'!) in order to match as wide a range of sources as possible. Unfortunately, I found it all too easy to overload the inputs, yet keeping the level back didn't give me a hot enough signal into the vocoder. A compressor would help, but that's not really a sensible option if you're only using the supplied mic. The mic is suspended at the end of a long bendy plastic arm, and Korg warn against bending this arm any more than necessary; I'll admit to wondering how long this device would last with some players I could name! The quality of the mic, though, is well up to vocoding standards — in fact, it seemed to me to produce better results than a high-quality mic, probably due to the vocoder's analysers and filters having an easier time of it with an signal of slightly reduced bandwidth. One very useful aspect of this vocoder is that an external signal can be used as a Carrier if you wish, so you're not limited to the classic '70s-style 'robot voice' effect, where a voice is used as the modulator, and a synth pad as the carrier; you could, for instance, vocode rhythm guitar with a drum loop. There's certainly no shortage of creative possibilities!

 

Effects, Arpeggiation & Global Settings

The Microkorg has are two onboard effects types: modulation and delay. Modulation effects are confined to three basic types: a flanger/chorus, ensemble effect and phaser, and the only controls provided are speed and depth. The Delay effects also come in three flavours: stereo delay, cross delay (where feedback is interchanged between left and right) and left/right delay (ie. stereo ping-pong). Despite their simplicity, the effects are of good quality. I particularly liked the phaser: it seemed capable of bringing out a certain 'graininess' in the synth's sound that reminded me of an old MXR stompbox.

In addition to the two effects, a two-band equaliser puts in a welcome appearance too. This seems to be standard fare for the current crop of analogue-modelling synths, but Korg offer sweepable frequency bands, which increases the EQ's usefulness.

The onboard arpeggiator offers six basic types of arpeggio, including up, down, up/down and random settings. A further 'Trigger' option is not strictly speaking an arpeggio at all, but is very handy nonetheless; it allows staccato chords to be retriggered at the arpeggiator tempo. The arpeggiator allows a very generous degree of control over its abilities, including note resolution (which is adjustable from quarter- to 24th-note settings), gate time (0 to 100 percent), range (one to four octaves) and swing (-100 to +100 percent). The number of arpeggio steps can be set between one and eight, and the arpeggiator may be set to run freely, or to retrigger from the start of its pattern with every key press. An option to latch the arpeggio after all keys have been released is also provided, but it would have been nice if this control had made it to a dedicated front-panel button. The arpeggiator can act on either or both of the synth's Timbres.

Not a bad range of connections for such an affordable product — there's the full complement of MIDI connections (no dual MIDI Out/Thru here), plus the two sets of audio inputs and headphones socket. It's a shame there are no pedal connectors, and there's only a stereo output, but this is hardly unreasonable at the Microkorg's price.

It's a nice touch that when you're editing an arpeggio, the Program Number buttons light to represent the active steps in the current arpeggio pattern. By turning individual steps on and off with these buttons, it's possible to modify the arpeggio's rhythmic pattern. If you don't have fun with this, it's time to take up a new hobby!

Global settings determine the Micro's master tuning, transposition, and whether signals arriving at the audio-input sockets will be passed through to the synth's audio outputs. That the Micro's keyboard is velocity sensitive at all must be seen as something of a bonus, so I was surprised to see a parameter to alter the keyboard's velocity curve. It was slightly disappointing, then, to realise that this actually only allows the selection of the keyboard's 'normal' velocity curve, or to fix the velocity output at a predetermined (ie. non-velocity-sensitive) value between 1 and 127. I was extremely pleased, though, to see an option to determine the routing of external MIDI. Essentially this enables an external keyboard to act as if it were the Micro's own keyboard, with its signal capable of triggering arpeggios, or alternatively to bypass the arpeggiator and play the synth's Timbres directly.

MIDI Capabilities

While we're on the subject, the Microkorg's MIDI capabilities are not to be scoffed at either. Local control can be switched on or off, and the synth will respond and transmit on any of the 16 channels, although there doesn't seem to be an Omni option. The Microkorg will also send or receive MIDI Clock messages. In addition to the usual discussion of note, control and SysEx implementation, Korg have included a very comprehensive section in the manual detailing the Microkorg's many MIDI NRPN messages. These allow the user an exacting degree of control over the arpeggiator (even allowing it to be switched on or off over MIDI) and the vocoder, to name just two parts of the synth. If you're not afraid of using controllers, there's a great deal of power to be tapped here. I tried a few examples using a combination of controllers sent from Cubase and my old Kawai MM16 fader bank, and can happily report that everything worked fine.

A MIDI filter feature can be accessed by holding down the Shift key and hitting Program Number button 4; here program changes, control changes, pitch-bend and SysEx messages can be selectively removed from the MIDI stream. Holding down Shift and hitting Program Number key 5, on the other hand, allows you to specify the control message transmitted by many of the Microkorg's parameters. This in turn enables you to use the Microkorg as a programmer for software synths, and makes it an viable companion to a compact, computer-based recording setup. Combine this with the Microkorg's option for battery operation and it's not hard to imagine a neat laptop system with this synth in tow — though dedicated USB connectivity would have made this neater still.

  User Interface  
  There aren't a lot of controls on the Microkorg's top panel; this is clearly a synth designed with speedy live editing in mind. To the left is the volume control, the arpeggiator On/Off button with associated LED tempo indicator, and a pair of tri-colour up/down keyboard transpose buttons. Both pitch and mod wheels are present, though they are slightly smaller than those on a less size-conscious synth; as a result they are a little more difficult to use with subtlety. Further to the right are the Program selection controls, audio input activity LEDs, the three-character LED display, and Write and Shift buttons. To the right of the Program Selection controls are the Edit Select controls (see above). The rest of the control surface is taken up with the printed matrix of program/vocoder parameter descriptions and the five Edit Controls (above).

The Edit Controls are normally assigned to adjust (from left to right) filter cutoff, filter resonance, envelope attack, envelope release and arpeggiator tempo, but once the Edit Select controls have been moved, the five knobs then control the corresponding parameters denoted in the screen-printed matrix below. Alongside the Edit Controls is an LED that lights to indicate when the physical position of the control being moved matches its current parameter value. This is important since in order to prevent sudden jumps when editing, you have to turn a control to pass through its original value before any changes take place. While this is undoubtedly useful in a live context, I did find it becoming annoying in the privacy of my studio, and would have liked the opportunity to turn the feature off. Fine incremental edits are carried out by using the Octave Shift buttons while holding down the Shift button, and holding down both Octave Shift buttons resets a parameter to its original stored value.

 

Sounds

Whilst I'm suitably impressed by the Microkorg's extensive synthesis capabilities (as I was with those of the MS2000), I have to say that many of the presets don't truly do it justice. I'm the first to admit that this is largely a matter of taste, but I think it would be a shame if the Microkorg's presets remained in place, as they might if users don't wish to tangle with the editing interface. There are some good factory sounds in there, but there are also some turkeys just waiting to be overwritten — maybe that's Korg's ploy to encourage you to come up with material of your own! Probably due to the restricted polyphony on offer, there aren't many pads, but I programmed a few of my own and achieved acceptable, if slightly 'cold' results — even allowing for the polyphony. Some of the basses, on the other hand, are superbly fat, and there's enough edge in many of the lead sounds to cut through the densest of mixes. Chunky sequence lines are also handled with aplomb.

Conclusions

I'm finding it hard to sum up my feelings about this synth. The synthesis engine is first class, and the vocoder is up there with the best of the current breed, but I can't help feeling they have been delivered in the wrong box! The mini-keyboard is where the problems will start for serious players, and although it has MIDI inputs so that you can connect a full-sized keyboard, it can't be rackmounted. Gigging DJs might be interested in the vocoder and hands-on filter tweakability, but the powerful synthesis features are unlikely to be tapped by that market — indeed they might even prove off-putting. For the serious synthesist who will find these features attractive, there's plenty of depth and flexibility here, but accessing it via the Microkorg's interface can be frustrating. It's to Korg's credit that they have designed an editing system that works as well as it does, with so few actions needed to leap between so many parameters, but although I was itching to get at the controls, I was slowed down greatly by the need to keep running my finger along the printed matrix and spinning the Edit Select knobs to get at the parameter I needed. Maybe time would bring familiarity.

Then there's the price... if the Microkorg had cost three hundred quid instead of four hundred, I could have forgiven it a lot, but as it is, there are other synths within reach that are also worthy of a close look, such as Novation's A-Station. The second-hand market is also beginning to pass down machines such as Roland's JP8080 (which also contains a very capable vocoder), and even Korg's own MS2000 and MS2000R are also available at a not-too-dissimilar price.

In short, the Microkorg has plenty of positive aspects and some negatives. It's a powerful synth in a compact, affordable package, but you have to go through a fair bit of button-pushing to tap that power. It offers flexible vocoding options with a dedicated ready-to-use microphone, and if you like the idea of working on the move, the battery operation will be a godsend to you, but you may not like the mini-keyboard and limited polyphony. Personally, I felt that the Microkorg's compromises might prove too much to accept — but depending on your priorities, you might feel it's made for you.

 information
£399 including VAT.
Korg UK Brochure Line +44 (0)1908 857130.
+44 (0)1908 857199.
Click here to email
www.korg.co.uk
www.korg.co.jp

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