You are here

Korg X5

AI 2 Synthesizer By Derek Johnson
Published January 1995

The X5 is Korg's cheapest fully‑featured keyboard synth, with a spec that belies its modest price tag. Derek Johnson finds out whether it's really the bargain it seems.

Last July's British Music Fair saw the unveiling of Korg's cutting‑edge Wavedrum percussion synth (see review in November SOS), which understandably grabbed a lot of the limelight on the Korg stand. Slightly outside that limelight, but likely to be of interest to rather more musicians, due to its price tag, was the new X5 synth, which impressed the SOS team on a number of points — not least its compactness and superficial cosmetic similarity to Kawai's perennially popular cult second‑hand buy, the K1.

The X5 is a 32‑voice polyphonic, 16‑part multitimbral, General‑MIDI compatible digital synth sporting Korg's AI2 synthesis — the same method as that found on the 01/W and subsequent Korg synths. Look at the X5 as an 05R/W with a keyboard (and the 05R/W was itself more or less an X3 without a keyboard — confusing, isn't it?), and you'd be in the right ballpark.

Anyone familiar with virtually any Korg synth released since the appearance of the now classic M1 in 1988 will know exactly what to expect. This is a 'Sample + Synthesis' (S+S) instrument, equipped with 6Mb of waveform ROM. That provides 340 Multisounds (multi‑sampled waveforms, including eight preset drum kits) plus an additional 164 percussion samples for use in the two user‑definable drum kits. The basic waveforms are of good quality — clean, bright samples with hardly a buzzing loop in sight. There are compromises on the multi‑sample front — the basic acoustic piano waveforms, for example, have some rather obvious crossover points — but this is hardly noticeable when you're actually playing the X5. Apart from straightforward, 'bread‑and‑butter' instrumental samples — piano, strings, guitars and so on — there is a healthy and varied selection of basic sampled synth waveforms and off‑the‑wall noises.

Each basic Program consists of one or two waveforms, coupled with a comprehensive selection of synth editing parameters. There are 100 user‑editable Programs, plus a bank of 136 preset General MIDI‑compatible Programs. In common with previous AI/AI2 instruments, the X5 also has a bank of Combi(nation)s — 100, to be exact — each of which can comprise up to eight Programs. The X5 also features a single, 16‑part multitimbral setup that's optimised to play back GM standard files. Effects aren't left out of the equation: the X5 sports dual stereo multi‑effects processors, with a choice of 47 different effects.

On The Outside

We've established that the X5 is physically compact and internally related to the Korg synths that have gone before. The front panel once again shows the Korg pedigree, with a backlit LCD and a selection of chunky clear buttons, some of which light up when selected. There are dedicated buttons for selecting Programs (a Bank button toggles between the GM and RAM banks) and Combis, for entering edit or global modes, and for choosing the multitimbral setup. A numeric keypad, value and parameter page buttons, and a data slider round out the control panel. Round at the back, there's a simple stereo output, MIDI connections (In, Out, Thru) and a computer connection marked 'PC to Host' (more on this later). Footswitch and volume pedal also have a socket each; the volume pedal can be used to control volume or filter cutoff, and the footswitch can be used as a sustain pedal, to scroll through programs, or to turn effects on or off. Power comes from an external supply — a backwards step, perhaps. The X5 does sport a headphone socket (on a stereo mini‑jack), which is, thankfully, at the front of the unit.

On The Inside

Programming the X5 is exactly as I remember programming the M1:

  • Multisounds/Programs: you can choose one or two 'oscillators' (Multisounds) for each Program, and alter the range of synth parameters for each Multisound. These parameters include a fairly traditional synth signal path: each oscillator is treated by its own modulation generator and passes through its own VDF (Variable Digital Filter), with attendant Envelope Generator, and a VDA (Variable Digital Amplifier), which also has its own EG. In addition, each Program has a Pitch EG, as well as a VDF Modulation Generator. The resulting Program passes through the dual stereo effects processor, and that's it. The major compromise to keep in mind here is that if you use two 'oscillators' (Multisounds) per program, the X5's polyphony is halved to 16 voices. Note also that the otherwise excellent filter lacks a resonance control.
  • Combis: As mentioned earlier, the X5 has a bank of 100 Combis. Here, up to eight Programs can be combined, with their own volume level, MIDI channel, transpose value, detune value, top and bottom key (for keyboard layering), and velocity high and low values, as well as pan position and effects send values. A Combi can be an 8‑part multitimbral setup (with each Program on its own MIDI channel), or can provide the player with comprehensive key and velocity layering and splitting facilities — great for producing impressive sounds in a live setting.

For a more comprehensive multitimbral setup, press the Multi button. This is optimised for General MIDI use — a GM sequence will be reproduced perfectly on the X5, with all the correct Programs being chosen from its GM sound bank. The Multi section can access all Programs, however, not simply the GM Programs, simply by using Bank Select messages to access the Programs in the RAM bank.

Two features that I particularly like are the inclusion of 10 alternate tunings (including Arabic, gamelan and pure major), a user‑definable tuning — even my Yamaha SY85 lacks this option — and drum kits that respond to pitch bend. This last point may be of limited use to most people, but it's good to see it included.

It's More Fun To Compute

Apart from not transmitting aftertouch from the keyboard, the X5's MIDI implementation is very good, with no gaping holes. One really neat point is the inclusion of a socket for direct connection to a computer. Korg's optional connection kits include a cable and software driver disk for IBM compatible or Macintosh computers. I used the X5 with an office Mac and found no difficulties — I installed the driver and connected up the keyboard and had instant, painless access to various bits of sequencing software. In fact, I ran the X5 during my review of Opcode's great new Overture scorewriting package, seen in last month's SOS; it operated flawlessly and sounded pretty good too.

The X5's compact size and great complement of sounds make it an ideal candidate for the desktop musician. If you are running a PC or Mac‑based system, a keyboard such as the X5 will provide you with cost‑effective, yet quality sounds, a nice keyboard, and a computer interface all in one box. It certainly beats the sound quality of the average budget PC sound card by a long way. Admittedly, there are a number of sound modules that come equipped with MIDI interfaces, which is a very tidy facility in itself, but having the keyboard in the same package is even tidier. Add the connection kit and a pair of headphones, and you're up and running.

Advanced MIDI users will welcome the comprehensive MIDI specification chart at the back of the manual, and if you're in any doubt as to how to connect the keyboard up to a computer, the manual provides very clear instructions.

Adding It All Up

While the X5 may offer nothing wildly original, it certainly has its attractions. Not for nothing is the M1 a classic, and the X5 provides the latest generation of this technology in a highly affordable package. It simply oozes classic and classy sounds, and you can afford it — honest! As an entry level synth, this instrument's spec certainly belies its low price.

However, I must point out some entries that appear on the negative credit list. First of all, as I mentioned earlier, the velocity‑sensitive keyboard doesn't transmit aftertouch — the X5 does respond to aftertouch, and it can be transmitted by the mod wheel, but there's no joy from the keyboard, I'm afraid. In common with other M/T/0‑series Korg synths, the X5's filter — which is otherwise a musically useful device — lacks resonance; some users may find the single multitimbral setup to be not quite enough, and the fact that it resets itself each time you turn the power on can be a bit frustrating; I've mentioned the external PSU already, and no, we don't like them; and remember that the nominal 32‑voice polyphony will be reduced to 16‑voice polyphony if you use two‑waveform programs — though, in fairness, this type of waveform/polyphony trade‑off is the case with most modern S+S synths.

But I only mention these demerits for the record. The bottom line is that the X5 offers Korg's established AI2 synth system, in a keyboard, at its lowest price point yet, just £799. At this price, these niggles can be rebutted in one go, and what's more, the X5 has little competition. Off the top of my head, Ensoniq's SQ1+ retails for £899 (though it adds a 16‑track sequencer), and only Yamaha's much simpler SY35 is actually cheaper at £599. The only other way you'll beat this price is by going for an up‑market home keyboard of some kind — bang goes your street cred (Elitism rools OK — Ed.).

Many GM‑dedicated instruments lose out on editing facilities — not the X5. It's a real synth with as many synth parameters and effects as you could reasonably expect, meaning that, for once, the fiscally challenged can go for the cheapest option without losing out on sounds, editability and fun — and let's not forget the computer interface. Good move, Korg!

It's A Family Affair

Korg's family of AI and AI2 synths now covers a wide range of current and discontinued instruments; here's an abbreviated list, which is limited to those reviewed in past issues of Sound on Sound.

  • M1 keyboard synth (uses AI synthesis; reviewed August1988).
  • M1R rack synth (AI; reviewed July 1989).
  • T2 keyboard synth (AI; reviewed December 1989).
  • 01/W FD keyboard synth (AI2; reviewed October 1991).
  • 01/W Pro keyboard synth (AI2; reviewed June 1992).
  • 01/W Pro X keyboard synth (AI2; reviewed June 1992).
  • 03R/W synth module (AI2; reviewed May 1992).
  • 05R/W synth module (AI2; reviewed October 1993).
  • X3R synth module (AI2; reviewed February 1994).

X‑Ray Spec

  • 6Mb waveform ROM with 340 multisounds and 164 percussion samples.
  • 32‑voice polyphony.
  • Two independent multi‑effects processors with 47 effects.
  • Built‑in computer interface.
  • 61‑note velocity‑sensitive keyboard.
  • 100 User Programs.
  • 136 preset General MIDI Programs.
  • 100 Combinations.

X‑Citing Effects

  • REVERBS: Hall, Ensemble Hall, Concert Hall, Room, Large Room, Live Stage, Wet Plate, Dry Plate, Spring.
  • EARLY REFLECTION: ER1, 2 and 3 (ER 3 offers a reverse envelope).
  • DELAYS: Stereo, Cross Delay, Dual Mono, Multi‑tap 1 (2‑channel multi repeat delay), 2 (adds cross panning) and 3 (adds crossed feedback).
  • CHORUS: Left/Right out of phase, left/right in phase, Quadrature Chorus, Crossover Chorus, Harmonic Chorus.
  • FLANGER: left/right in phase, left/right out of phase, Crossover Flanger.
  • PHASER: Left/right in phase, left/right out of phase.
  • OTHER: Exciter, Enhancer, Distortion, Overdrive, Rotary Speaker, Auto Pan, Tremolo, Parametric EQ.
  • SERIAL COMBINED EFFECTS: Chorus‑Delay, Flanger‑Delay.
  • PARALLEL COMBINED EFFECTS: Delay/Hall, Delay/Room, Delay/Chorus, Delay/Flanger, Delay/Distortion, Delay/Overdrive, Delay/Phaser, Delay/Rotary Speaker.

X‑Otic Sounds

To get an idea of the sound of the X5, I can point you in the direction of all the M, T and 0 series synths that have gone before, with sparkly, rich sounds that are fun to play. The same goes for the 47 excellent effects. What's really remarkable, and you've probably gathered this from the main review, is that these sounds and these effects have been packaged at an unmissable price. Even though the style of sounds is quite familar, I find myself quite attached to a number of the factory Programs and Combis. Here's just a few of my personal favourites.


  • A07 The Strings: swirly, thick‑chorused ensemble strings that still impress without the effects.
  • A30 Space Wing: a sweet, ethereal sound with a shakuhachi‑like attack and a lush fade‑in.
  • A37 Chamber Ens(emble): live‑sounding, in your face small string section.
  • A63 Whirly: electric piano with an edge when played hard.


  • 00 Star Burst: musically pointless but exceedingly impressive texture. Hit lower octaves hard for instant dive bombing, while sparkles fade in and out in the upper octaves.
  • 05 Calcutta: nice ethnic feel, with velocity switched tablas and split santur/strings. Instant Bollywood.
  • 47 Orchestral: the name says it all; a classy, classic layer of woodwinds and strings.
  • 89 Death Stars: Seriously gloomy texture, with explosive attack at high velocities.

The GM bank of sounds is also very good. It has high and low points, as with any manufacturer's interpretation of the spec, but in general the quality is high.


  • Compact and light.
  • Very nice sounds and effects — no compromises here.
  • Computer interface.
  • Excellent value for money.


  • No aftertouch from keyboard.
  • No filter resonance.
  • Only one multitimbral setup.


A worthy instrument at an extremely fair price. The X5 could well be this season's 'must‑have' synth for newcomers to the marketplace.