Korg Kronos

Honey, they shrunk the OASYS. Well, its weight and physical size.
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By Stephen Fortner

Honey, they shrunk the OASYS. Well, its weight and physical size. In nearly all other respects, the Kronos, which debuted at Winter NAMM 2011, equals or surpasses the features and sounds of Korg’s groundbreaking (and now discontinued) do-it-all behemoth. More significantly, Korg shrunk the price from the OASYS’ rock-stars-only $8,000 to a level that’s competitive with the other flagship workstations and multi-sound-engine gig keyboards currently on the market. Let’s dive in and try to answer the intentionally provocative question we asked on this issue’s cover.

Getting Around

Got a gig that requires a tuxedo? With its piano-black cheek blocks, burnished gun-metal body, and icy white LEDs that light the buttons and main joystick, the Kronos looks like it’s already wearing one. In the studio, the printing on the panel looked readable enough, but tended to wash out under changing stage lighting. Fortunately, the “Control Surface” view is an onscreen duplicate of the knobs, faders, and all the buttons that select pages of functions for them. You can see (and change) all the assignments from here, and thanks to the visual correspondence between screen and panel, the Control Surface view is the best way to get fluent in using the physical controls.

The OASYS’ touchscreen was larger, but the Kronos’ is higher-res: 800 x 600 as opposed to 640 x 480. Th ose extra pixels make small fonts more legible. Single-touch operation may seem old school, but unlike today’s smartphones, you can navigate the Kronos with a stylus or fingernail, which I found works best when selecting stuff from optionpacked pop-out menus. The screen almost always refreshes instantly when you do something—some other keyboards have some catching up to do there.

Editing is made easier by several ways of changing values. Let’s say you tap a filter cutoff knob onscreen. The Value fader to the display’s left will sweep it quickly, while the main data dial to the right moves it slowly—coarse and fine. You can also use the increment buttons, or type exact values on the keypad.

The only physical controls you give up compared to the OASYS are the velocity-sensitive pads that triggered drums or memorized chords. In their place is a touchscreen page with eight playable strips—the vertical axis translates to velocity.

I will say that Korg has favored a low-profile look over a touchable feel—I prefer the chunky, rubbery knob and fader caps on the Yamaha Motif ES and subsequent models, not to mention the slightly longer throw of their faders. Points for the Tap Tempo button, but what—no dedicated octave shift buttons? Instead, the assignable switches above the pitch/modulation joystick do this on a per-sound basis.

Synth Engines

The Kronos comes closer to the experience of having a music laptop stocked with your favorite virtual instruments than any self-contained keyboard yet has, minus the usual computer headaches. Seven of the nine instruments here were either originally part of the OASYS or later released as expansions for it, but the first two—the SGX-1 acoustic pianos and EP-1 electric pianos—are exclusive to the Kronos.

SGX-1 pianos. For me, the “bank A, program 1” acoustic piano sound has never been the strong suit of Korg workstations. Good enough for the gig, but no industry leader. The Kronos does a dramatic 180, with the best sounding factory pianos ever to show up in a workstation.

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The two main piano flavors are full-bodied “German” and brighter “Japanese” grands. Both sound gorgeously detailed in recordings, and the brighter variants of each cut through a live rock mix without sounding brittle. Each piano streams 4.7GB of full-length samples from the internal solid-state drive, so you’ll hear no loops, no phase weirdness, no unnatural decay, and no clunker notes with skewed harmonics. Switches between the eight velocity layers are nigh imperceptible.

Lid position, sustain pedal resonance, mechanical noise, and release sample volume are all adjustable, as is whether you hear the stereo picture from the audience or player’s position. The best pianos in a plug-in like Synthogy Ivory use several times more memory, and you will hear that difference listening carefully to solo piano pieces. I also wouldn’t say the Kronos deals a clear drubbing to high-end digital pianos like the Roland V-Piano or Yamaha CP1. But the fact that those are more relevant comparisons than other workstations—and they are—is really saying something.

EP-1 electric pianos. Th e mighty OASYS relied on “regular” multisamples for its vintage electric pianos. EP-1 is in a whole other league. Two reed (Wurlitzer) and four tine (Rhodes) pianos are on hand, including a Dyno. Details you can tweak include hammer width, attack brightness, and release noise. You can insert one of nine virtual stompboxes, including the must-have MXR Phase 90, and cabinet modeling simulates either the Fender Suitcase amp or the internal speakers of a Wurly. How does it all sound? Real. Bass bark and mid-high pop jumps out of the speakers when you spank the keys. Play delicately, and you’ll get beautiful ballad timbres. Ask for the dynamic range between those extremes, and you’ll get all of it. A+.

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CX-3 organ. Korg recently discontinued the “new” CX-3 as a standalone B-3 clone, but it lives on inside the Kronos. You get splittable upper and lower drawbar parts (but no bass pedal part), and Korg’s EX drawbars if you want to add four harmonics not found on the real thing. Sonic details such as leakage, percussion, and vibrato/chorus are deeply editable, as is rotary simulation—you get separate speeds, speed-up and slowdown times, and mic placement settings for the treble and bass rotors.

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I give the organ model itself a grade of A, and the rotary effect a solid B+. It was one of the best available when Korg introduced the new CX-3, will still make organ fans at any live gig wonder where you hid the Leslie, and is certainly as good as it gets on any workstation. Listening in isolation, though, I felt that a couple of dedicated clones I’d recently reviewed (the Studiologic Numa Organ and Nord C2, both in May ’11) treated high frequencies a bit more realistically at fast rotary speed.

AL-1 synth. Any attempt to describe this analog-modeling monster concisely is doomed to be a gross understatement of its depth. Just a few highlights are two oscillators with continuously variable waveforms; a suboscillator you can swap for external audio input; dual multimode filters with serial or parallel routing, plus a “Multi-Filter” that can morph between two types in real time; hard sync and audio-rate FM; five fivesegment envelopes; and seemingly bottomless modulation options, including a step sequencer that can “play” any eligible destination.

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More significant than any of this is the sound quality of the modeled waveforms and filters. It’s simply unparalleled. There’s no appreciable aliasing, even on very high notes, and no stepping or zipper noise when you sweep parameters. To sound any more analog than this, you need a real analog synth.

PolysixEX and MS- 20EX synths. Know what I don’t like about these replicas of Korg’s classic Polysix and MS-20 analog synths? Nothing! In short, they sound like the originals. Only with more polyphony and the ability to be layered with other sounds, routed through effects, and modulated a zillion ways from Sunday. Korg elegantly handles the MS-20’s patch panel on the touchscreen: Tap any jack twice, and a flashing yellow square surrounds it. Tap the second jack, a patch cable appears, and your connection is made. The Kronos won’t let you do things that don’t make sense, like connecting two outputs together. If you’re new to synth programming, either of these synths serves up more instant gratification than AL-1, and both have markedly different sonic characters as well.

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MOD-7 VPM synth. Imagine a Yamaha DX7 with a modular patch panel that lets you alter or override the algorithms for how the operators interact. Imagine that the operators could make not just sine waves as on the DX7, but saw, square, and triangle—or use a waveshaper to get more harmonically complex results. Imagine you could also use multisamples as modulators, or just patch them in as a separate layer. That’s the very tip of the iceberg of MOD-7, a variable phase modulation (VPM) waveshaping synth. If you don’t need a sound designer’s paradise, just enjoy the factory sounds, which range from DX-like to surprisingly analog sounding—a testament to how sonically versatile FM synthesis can be. The kicker: If you can get original DX7 sys-ex files onto a USB drive, MOD-7 will load the sound banks.

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STR-1 string modeler. I could joke about “string theory” in quantum physics, but in fact, Korg’s modeling synth for plucked strings is a little easier to understand. “Plucked” understates its capabilities, as it can also sound like the virtual strings were struck, bowed, scraped with car keys, or vibrated in other ways. Anything from acoustic guitars to John Cage-style prepared pianos to resonant drones reminiscent of Star Trek: The Motion Picture is possible. You can decide not only what kind of string is used, but how and where it’s “excited” as well. Similar to MOD-7, you can layer a PCM sample, or actually use its attack transient as your “pick.” Bonus: Both MOD-7 and STR-1 give you the same dual filter setup, including the Multi-Filter, as AL-1.

HD-1 engine. All the previous sound engines come under the umbrella term “EXi” for “expansion instruments,”—ironic, because it implies they’re add-ons when they seem more like the star attractions. The Kronos also packs the core sampling engine from the OASYS, called HD-1. An HD-1 program can have one or two “oscillators.” An oscillator is really a complete synthesizer that plays up to eight velocity-crossfaded multisamples, any two of which can “speak” as a non-switched, full-time layer. Any of the eight slots can also hold a tempo-synced wave sequence. You effectively get all of the moving, morphing madness of Korg’s classic Wavestation synth, as you did on the OASYS.

On the Kronos’ internal solid-state drive, you’ll find every EXs sound expansion pack Korg created for HD-1 since the OASYS era; the new ESx4 Vintage Keyboards library is my favorite, and I like its Clavinets better than any that the STR-1 string modeler can cook up. (Korg, please make an EXi that does for Clavs what EP-1 does for electric pianos!) The Kronos preloads selected instruments on power-up into the 2GB of sample RAM—there’s actually no factory ROM. Officially, sample RAM isn’t user-expandable, though some clever folks at korgforums.com have done this (and installed larger SSD drives) fairly painlessly. Since opening the Kronos will void your warranty, we recommend waiting for Korg to make any expansion options official.

Sound Quality

I could take up the rest of this issue describing the variety of sounds in the Kronos. Instead, I’ll call out what they all have in common: pristine audio fidelity. From synths to saxes, pianos to piccolos, and tympani to TR-808s, everything sounds smooth, rich, and not at all grainy. Things that are supposed to be punchy, like kick drums and synth bass, kick you in the gut. Things that are supposed to be crystalline, like wave sequences you’d layer over pads, swirl around your head. Things that are supposed to be warm, like analog brass, are.

Is there any sound category where the Kronos could do better? Acoustic and electric guitars come to mind. The best specimens come from the STR-1 string modeler, but somewhat surprisingly, my aging Motif ES has more of what I want to hear in this area. Also, while the acoustic string, brass, and woodwind patches (all from the HD-1 engine) offer lots of variety for pop and R&B lines, I’d like to see more power-user features for these sounds, such as proactive, realtime articulation management, voice allocation for divisi, and other stuff a composer would want for serious mockups of orchestral scores. Roland’s “SuperNatural” and Yamaha’s “Expanded Articulation” technology have some of these moves, and the Kronos’ stellar job on piano, keyboard, and synth sounds is raising my expectations here. There’s no reason a future Kronos EXi couldn’t work similar magic for orchestral sounds.

Usually, no matter how good a keyboard’s sounds are individually, if you do an entire multitrack production on one instrument, the results will sound kind of glassy. Some audio experts blame it on hearing everything through the same digital-to-analog converters. Whatever the reason, the Kronos seems to suffer from this less than any other keyboard in recent memory. Its EXi instruments have distinct enough characters to create a convincing illusion that your all-in-the-box song used a bunch of different keyboards.

“Smooth sound transition” is Korg’s term for the fact that changing sounds doesn’t cut off sustained notes. Other keyboards have done this, but the Kronos is especially fluid. You won’t even hear any audio “bump” normally caused by effects switching, and it works in all play modes regardless of whether you change sounds with the dial or increment buttons, by tapping a slot in a Set List or the category browser, or via the numeric keypad. It only retains notes from the most recent sound played, so two consecutive program changes will cut off the audio—of the first program but not the middle one. This is the best implementation yet of a feature that should be required on all keyboards by law.

Dual Programs

On the Kronos, a program can be what’s effectively a two-way combi— though it lives in a single program slot and you’re not in Combi mode. Th is can be quicker and more intuitive than dealing with all the options of Combi mode, especially if all you’re after is a simple split or layer.

With EXi sounds, you can simply touch-select a second instrument (SGX-1, EP-1, etc.) under “EXi2” on the “Common” page and just start tweaking until it sounds good. Better, if you remember a layer you like from some other program, use the “Copy EXi Oscillator” function to grab it with all its settings intact. I do wish this function let you browse sounds by category as you otherwise can on the Kronos, but it’s by bank and number only. You can also quickly set keyboard zones for each instrument, and mix their volumes using the first two faders.

You can stack any two EXi instruments, or create dual HD-1 programs, but you can’t combine EXi and HD-1 sounds in the same program. (In fact, HD-1 and EXi programs have to live in different banks.) Of course, you can pop up to Combi mode and freely combine programs that use EXi and HD-1 sounds. All in all, creating dual programs feels less like “programming” and more like being in a virtual music store, happily stacking keyboards atop one another.

Song Recording

The Kronos’ facilities here are more like a computer-based DAW than any other keyboard workstation’s are. Alongside the usual 16 MIDI sequencer tracks, you can record up to 16 audio tracks to the internal solid-state drive. Audio tracks are mono, but you can link them in stereo pairs. Up to four tracks can be recorded at once, and 24-bit resolution is now supported, though the sample rate is still fixed at 48kHz. Th e two balanced 1/4" audio inputs around back each have a trim pot and mic/line switch, but neither handles high-impedance signals, so you’ll need a preamp to get proper tone from most electric guitars. Other input choices include optical S/PDIF, any of the Kronos’ internal busses, and even streaming over USB, as the Kronos is also a USB 2.0 audio interface.

Audio and MIDI track mixers are on separate screens for space reasons, but a unified Track Edit view shows all tracks together, along with the master track that handles such things as in-song tempo changes. Here, you can issue track-based, measure-based, and (for MIDI) note-based editing commands, as well as do step recording. Some commands take you a level deeper, where you’ll find features like a MIDI event list and zoomable audio wave editors.

Th e sequencer/recorder is so similar to the OASYS—virtually identical, in fact—that instead of excavating more features I’ll just say that recording on a standalone keyboard doesn’t get more powerful than this. Any nitpicks I have don’t concern what you can or can’t do, but occasional quirks of how you do it. For example, I’d prefer that touching the onscreen fader for a given MIDI track let you play its sound on the keyboard. Instead, you have to select the track from a pop-out browser above the mixer area. Along similar lines, the Track Edit overview could use a zoom function and a more visible play wiper than that little yellow dot that ticks across the timeline.


Both for sheer effects power and for handling routing, the Kronos slams it out of the park. You can run up to 12 insert effects simultaneously, plus two “master” (send-based) effects. Then, two “total” effects are on the final output, downstream of any other routing. Good choices for this stage include a multiband compressor, mastering limiter, reverb, or any other final spit ’n’ polish.

Best of all, when dealing with complex songs or combis, or processing external audio through the effects, you can bring up routing diagrams (shown above) that make it crystal clear what’s going through what—no small feat given the extensive bussing possibilities. As to effect types, about the only thing I couldn’t find was convolution reverb (though there are plenty of conventional reverb options), probably because it’s such a CPU-hungry process. For overall sound quality, these effects easily compete with many dedicated plug-ins.

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Performance Enhancers

Even though we’re running out of room and the following features aren’t new to the Kronos, I’d be remiss not to mention them, as they add to the playing and composing experience.

KARMA 2. For the uninitiated, this latest iteration of programmer Stephen Kay’s realtime music generator can be oversimplified as a multitimbral, polyphonic arpeggiator on steroids—hence this section’s title! Depending on how it’s set up, it can sound close to arranger auto-accompaniment, create choppy dance floor effects, roller-coaster into unexpected musical twists, or do anything in between. It’s a world unto itself, and you can learn how it works at karma-lab.com.

Drum Track. Want straight-ahead rhythmic accompaniment? Either preset or user-created drum patterns can be set to play when you hit the keys. You can set the keyboard zone that triggers the pattern to start, mix any pattern with any kit, and even transpose the drum map by halfsteps with the Shift parameter, resulting in subtle to dramatic changes in the hits. Note that with some programs, KARMA will have drumming plans of its own even if the Drum Track isn’t active—though you can sync the two up.

RPPR. Short for “Realtime Pattern Play/ Record,” this long-standing Korg feature lets you record patterns using the sequencer, then assign them to keys for tempo-synced triggering. Patterns can also be set to trigger at pre-determined points in an otherwise linear song recording.

In-track sampling. One of the many abilities of the Kronos’ full-featured sampler is to assign a given bit of sampled audio for triggering via a MIDI note in the sequencer. In ReCycle fashion, you can also slice audio according to the transient peaks, then trigger each slice separately, or time-stretch the lot to song tempo.

Vector joystick. Able to map multiple parameters to its X and Y axes, the Kronos’ “other” joystick is, at minimum, a high-powered macro-morpher. The “vector envelope” can even automate a series of joystick moves in sync with tempo. As on the classic Wavestation, vector envelopes are used to particularly animated effect with wave sequences, but nearly every program in the Kronos employs this joystick in some musically pleasing way.

AMS. “Alternate Modulation Sources” is Korg’s term for programmable modulation routings—they’re alternate relative to the defaults. The real power is in the AMS mixer, which is how you tell the Kronos, “Modulate this with that, by way of another thing.” A simple example is vibrato: varying oscillator pitch via an LFO, with the joystick controlling depth. But the selectable mixer algorithms can get much more sophisticated about how the two modulation sources interact—they can add up, multiply, off set one other, or use more complex if-then logic. Maybe only hardcore sound designers will spelunk this deeply, but it’s nice to know that whether you’re an audio mad scientist or just want awesome Rhodes and synth sounds for “Living for the City,” the Kronos isn’t about to let you down.


Every once in awhile, a pivotal instrument truly raises the bar, and thus sets the tone for future industry competition, about what a given type of keyboard—workstation, analog synth, drawbar organ, stage piano—can and should do. This sure feels like one of those times. As discussed, there are some acoustic sounds the Kronos doesn’t render with the highest standard of playing realism—at least not right now. But right now, if I had to pick one keyboard to be marooned with on a desert island, the Kronos would be it. No other single product does this much, this well, all at the same time, at this price or anything close to it. That’s our definition of a Key Buy.


PROS Best acoustic pianos ever in a workstation. Electric pianos and drawbar organs could justify a keyboard in their own right; so could the virtual analog synths. Overall sound quality and diversity are stunning. Does 16-track audio recording. Lots of effects, and they all sound great. Plenty of polyphony for multiple synth types in a song or combi.

CONS Sample preload on power-up is convenient, but makes for long boot time. Neither sample RAM nor internal SSD are user-upgradeable. Segregation between HD-1 and EXi programs seems odd. Difficult but not impossible to hit that polyphony ceiling with dense songs or combis.

POLYPHONY Varies with instrument type; 80–200 voices.
RECORDING 16 MIDI tracks plus 16 audio tracks. Extensive automation and MIDI filtering. Track, measure, note, and audio waveform editing.
SAMPLING Full audio processing and editing functions, including sampleto- track and assigning loop slices to MIDI notes. Can sample to 2GB RAM or 30GB SSD.
SIMULTANEOUS EFFECTS 16 (12 insert, 2 master, 2 total).

PRICE 61 keys | List: $3,499 | Approx. street: $3,000
73 keys | List: $4,350 | Approx. street: $3,500
88 keys | List: $4,750 | Approx. street: $3,800


Set Lists

Korg may not have been first with a unified mode to access anything you need for the gig: patches, combis, or sequencer songs. Kurzweil’s Quick Access banks and Yamaha’s Master mode are similar ideas. The Kronos’ Set Lists take the idea to new heights, though. A Set List can have up to 128 touch-access slots in groups of 16 per screen. You can enter a name of up to 24 characters (e.g., a song title) and add notes of up to 512 characters—useful for a few lines of forget-prone lyrics. You can’t drag-move slots like they’re iPhone apps, but copy and paste functions let you reorder them. Last but not least, a nine-band EQ is exclusive to this mode and affects all slots in the Set List. This lets you grab the faders and adjust to the room acoustics without dealing with individual programs’ EQ settings.

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Keyboard Feel

Korg put fully weighted keys on both their 88 and their midsized (73-key) model, something we see on gig keyboards like the Nord Stage but not usually on full workstations. I found Korg’s RH3 action very non-fatiguing even for extended piano practice, and just right for electric piano sounds. My synth-accustomed fingers would have preferred a bit less weight for organ and synth licks, as I had to play more deliberately and thus more slowly. A 61-key semi-weighted Kronos is also available, of course. The aftertouch did a good job of translating the full range of finger pressure to smooth sonic changes, as opposed to going too quickly from zero to full.

*Go to korg.com/kronos and click "Hear Kronos" for factory examples.

*Video: First impressions in the studio.