Korg Opsix Altered FM Synthesizer ‘Reimagines’ FM Synthesis

Korg today officially introduced the Opsix, described as an ‘expansive reimagination of classic digital synthesis’.

The Korg Opsix is described as an “altered” six-operator FM synthesizer, because the keyboard’s sound engine goes far beyond traditional FM synth capabilities.

Although the instrument has a six-operator FM sound structure like classic FM synthesizers, the Opsix goes further, featuring new operator modes, 11 filter options, 30 effects, a polyphonic step sequencer and more.

The Opsix was originally previewed at this year’s NAMM Show. At that point, the prototype that they showed was more of a flagship keyboard design:

The Opsix that they are introducing, though, is closer in design to the recently introduced Wavestate. And that’s how they are positioning the new synth:

“Much like Korg did when bringing wave sequencing back in a more powerful, more musical, and more immediately accessible way with wavestate, so was the approach to FM sound generation of the opsix, resulting in another incredibly flexible and unique synth.”


  • True six-operator FM synthesis
  • Full editing with the DATA ENTRY knobs
  • Five operator modes that expand FM synthesis
  • 40 preset algorithms and user algorithms
  • Three EGs, three LFOs and 12 virtual patches offer an extensive range of modulation
  • Eleven powerful filters, including MS-20 and Polysix
  • Three series of 30 types of high-definition effects
  • Visual editing with a spectrum analyzer and oscilloscope
  • 16-step polyphonic sequencer
  • Add unpredictability to sounds with the Randomize feature
  • Favorite and smooth sound transition (SST) functions
  • Compact design featuring a 37-key keyboard

Korg Opsix Audio Demos:

Pricing and Availability

The Korg Opsix is expected to ship in December, priced at £699/€799. See the Korg site for more info.

45 thoughts on “Korg Opsix Altered FM Synthesizer ‘Reimagines’ FM Synthesis

    1. The cost of a synth has nothing to do with how many keys it has. It has to do with what is under the hood. This synth isn’t released yet so I personally do not know what I think yet. Spec-wise I’m not too convinced, but lets see what a full review reveals.

      1. “The cost of a synth has nothing to do with how many keys it has. It has to do with what is under the hood.”

        I think you’ve got it backwards. If you look inside a modern synth, there’s almost nothing there. But adding another octave makes a synth a lot bigger and heavier – making it more expensive to manufacture, store, ship, etc.

        Why do you think the Behringer knockoff keyboards all cut the keyboards down by an octave? It’s the easiest way to cut costs.

    2. $940US? I hope the street price will be a lot less. Yes, it does a competent job, as Mr. Bristow wrote. Nice, competent sounds.

      I hope we haven’t plateaued with FM synthesis.

  1. sounds really awesome, price seems a bit high, i think a price point similar to the Minilogue would have been great. i’d also like to see a keyless module version.

  2. The quote from Dave Bristow on the Korg website is pretty frank! It’s refreshing in an era of hyperbolism.
    For me it is tempting but I’ll pass, because I know I could link up my BCR2000 to dexed or FM8 or my DX11 to get a similar effect, but I haven’t, which probably means I don’t need to.

    1. Oh, this is a shame. The DXs were better in that they mostly had aftertouch and expression pedal and breath control inputs. FM really benefits from performance modulation. Not sure a keyless version could sell for much — why not just load up an FM VST.

  3. Make a modular and 5 octave version instead of this sh**..im realy getting tired of all these manufacturers with their 3 octave garbage.

    1. Unless you’re Rick Wakeman, you only need one good controller keyboard. There’s no point in paying hundreds of dollars extra for a room filled with massive 5 octave instruments. Let’s not forget that the DX7 was released in 1983 at a price of $1,995. Adjusting for inflation, that’s $5,213.44 today.

      1. A Prophet 5 Rev 3 was $4595 in 1982 … about $12K in 2020 dollars and of course no MIDI on the original. Even a 16-voice Moog One is something like $8500 today (though I don’t know its official MSRP if it has one.) Even these don’t seem too bad compared to the pricing of traditional instruments like acoustic pianos, which many people buy. A Moog or Prophet 5 seems likely to be a comparably worthy long-term investment.

        Maybe some of the synthtopia “it’s so overpriced” complaints are sidestepping the fact that we live in an insane era of embarrassing synth wealth and affordability, from cheap or free softsynths to behringer to modulars to analog reissues to boutique and monster synths.

    1. Minilogue XD and KARP odyssey both have desktop versions. Perhaps they don’t sell enough to make the module version worthwhile…

      I could imagine sub-1000$ synths to mostly sell to non-professionals who prefer keys, hence it doesn’t make sense to make desktop versions profitably.

  4. I have an old DX11 that is 8 part multi-timbral, but this new Korg appears to be mono-timbral? Is it that manufacturers now seem to think that as everyone is now used to analogue devices, that no one is interested in multi-timbral equipment? There does not seem to be an excuse for this when we’re talking about a digital instrument. Is this anything more than a DX7 with no multi-timbrality but with a tweaked sound generator, effects and a sequencer?

  5. It’s imaginative, creative, beautiful, superbly functional (which puts it head and shoulders above the vast majority of the hardware alternatives), and tempting as hell.

    Unfortunately, for most potential customers (pro or hobbyist) this price, combined with the lack of aftertouch and (yet another) severely limited keyboard, inevitably raises the question: can I afford spending €799 so I can do just a little bit more of what I can already do with my existing hardware controllers, a free DAW/host, and the free Dexed?

    There is no question that Opsix offers some unique features, but are those features in themselves worth the price given the economy and the speed of technological development…? (But it is so effing TEMPTING!)

  6. Sounds pretty decent. I could get a ton of great sounds out of this, wavefolder is a nice addition. Interface seems pretty good too. Well done Korg.

  7. I do like the ability to replace any OP with another filter, or an audio-rate modulated filter. The latter in particular is a very useful feature.

    That said, this strictly has ADSR envelopes, mono signal path before fx, no microtuning, and a poor choice of waveforms.

    And the results are what I’d expect. Bleggh. Sounds like a tin can.

    Designers need to pass a quiz on the SY77/99 before deluding themselves they are releasing the next generation of DX like FM.

    1. “Designers need to pass a quiz on the SY77/99 before deluding themselves they are releasing the next generation of DX like FM.“


  8. I heard quite a bit of zippering in the sweeps in the demo– I wonder if that was deliberate or just a short coming of the engine? Past examples of FM synthesis have not inspired my interest. This does appear to take it to a logical next level. I’ll check out Loopop’s in-depth review to get a better sense of it’s capabilities.

    1. In the manual it describes several LFO waveforms that are step quantized: TRI4, TRI6, SAW4, SAW6. Might have been one of those, in which case it was a deliberate patch design choice.

    1. Dull? If anything FM is known for producing “bright” and metallic sounds, though it can produce woody and fluty sounds as well. 😉

      FM was popular in the 2000s for making grungy sounds and the infamous “bass drops” but it’s a lot more versatile than most people seem to think it is.

  9. This seems like a bit of a hobbled ‘white elephant’ having an expressive synth engine with non-aftertouch keybed.
    Heck I’ve got 2* Novation SL controllers (37,48keys) both with aftertouch and this in a (cheaper) keyless desktop profile would be ideal.

  10. Skip to the 1 minute mark- they show off a filter mode called BRF.


    Never knew I needed a synth with puke mode. Well done, Korg. You just made another sale.

  11. How about what it gets right? The Opsix passes the “Does it sound good?” test, which is job #1. I have enough FM/additive tools, so this would be a sonic duplication for me, but its a smart way to fill the gap if you don’t. People who pair this with a Wavestate should get a free Korg t-shirt. They’d be great partners in weirdness. Those Randomizer buttons are a secret weapon.

    I can forgive the three octaves. FM always feels like one-handed lead/bass/effects material unless you’re one of those rare souls who sits and plays it like a piano. This ain’t for that, IMO. Its for composers, Kebu-stackers and (as Zaphod said) those who wisely use a controller, especially if its multi-zone-capable. Besides, see those +/- octave switches? Its at least 5 octaves inside. That should take some of the butthurt out of it.

  12. I wish the demos would spend less time trying to re-create the 80’s (although the Sakamoto homages on ‘Simple PWM’ & “Mallet Piano” are appreciated), and more time showing us what uncharted territories it’s capable of exploring.

    Also, it would be nice if you could load your own algorithms into the effect slots, as on the XD, Prologue, and NTS-1.

    1. As far as I can tell it’s the MOD7 engine from Kronos and Nautilus which was earlier VPM in the Z1 (and OASYS). So the only unchartered thing is the knobs and faders and colours. That sounds rude and I’m not meaning it that way, there was so much exciting stuff in the OASYS project that is still worth bringing to a bigger market.

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