Korg Opsix Synthesizer In-Depth Review

In his latest loopop video, host Ziv Eliraz takes an in-depth look at the new Korg Opsix keyboard synthesizer.

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

The video starts with an overview of the Opsix, and then digs into the details of the synth engine, effects, performance options and more.

Topics covered:

0:00 Intro

0:50 Overview

4:55 Randomization

5:30 Connectivity

5:50 Operator basics

9:05 Algorithms

12:10 OP envelopes

13:30 OP params

14:50 Ring mod

16:05 Filter mode

17:50 Filter FM mode

18:25 Wave folder

19:20 Voice filter

20:30 Effects

23:00 Arp, sequencer


25:55 Bi-timbral split

28:25 Tri-timbral seq

28:55 Velocity mod

29:30 More arps?

30:30 LFO key sync

30:50 Massive chords

31:20 Chord trigs

31:40 Seq to arp

32:00 Fake hard sync

32:30 Cutoff knob

34:40 Pros & cons

37:25 All 250 Presets

Check out the video and share your thoughts on the Korg Opsix!

29 thoughts on “Korg Opsix Synthesizer In-Depth Review

  1. I will watch this review in its entirety even though I have no intention of buying this synth because Loopop is just the best.

  2. Had a DX7 a long time ago….sold it….never regretted it. Korg did a good job on the Opsix, great sound and price…but I’ll never buy it …..Loopop’s review was awesome….as always!!!

  3. Yawn…aren’t people completely fed up with this FM stuff? Especially when there is already SO much of it out there….

    1. It’s FM but it also does wave folding and bread and butter VA sounds. Besides physical modeling, I love wave folding stuff; if you’re not into it, go grab yourself a Virus, modular system, Moog, etc.

    2. bad, lazy take. new ways of interacting with FM synthesis (and really, any type of sound generation) will always affect and change how people respond to it. changing the hands-on qualities of a synth will appeal to new people and change what FM engines spit out – not all FM synths are going to do the same things. new tools for working with the synthesis method will also yield imaginative new soundscapes. it’s fine that you’re not interested in this specific iteration for your own workflow, but scratching it as redundant just shows a lack of imagination on your part.

      1. I’ll be interested to see what comes out. But there must be a reason why yamaha didn’t put these sliders on most of the FM synths or on the Montage, apart from the cost. My theory is that these sliders alone aren’t enough to give a tangible grasp of FM, rather you have to have a grasp of all the different envelopes etc. and possibly do a bit of math with the Bessel functions.

  4. Its design reminds me a little of the MS2000–the odd blue, and the screenprinting. Not enough to convince me that it’s worth having in addtiion to a Digitone, though.

    1. I sold my digitone because the sounds I most enjoyed were polyphonic sounds and 8 voices are not enough for the music I make. The Opsix fixes that. But obviously very different machines.

  5. Maybe it will have a reasonable amount of bugs once they come out with the xd version in a year or two. Or, perhaps pajen will upgrade the firmware to a useable state for free once they drop official firmware support in a couple of months.

  6. First impression: wow I’m gonna buying this one.
    Then: mh, 3 octaves without aftertouch…
    So: back to my trusty VSTis.

  7. Does anyone think this really sounds good compared to the FM synth from 40 years ago?
    The OPSIX might look easy to use but isn’t sound the most important feature?

    1. I have a DX11 (=TX81Z keyboard version). Does it sound good? Yes and no. I can get some really wonderful sounds out of it, but it can also be quite lofi. Lots of noise, and aliasing with some sounds, especially when you play higher up the keyboard. But to me, this is the charm of old school FM, which uses early digital technology. I don’t think you could get such a textured sound out of the Opsix (I wasn’t able to do it with either Operator or FM8). Just offering the same possibilities (number of operators, waveforms, etc) as the old machines doesn’t get you their sound, the limited specs are an integral part of the sound. But maybe the Opsix also includes options to make it sound more like oldschool FM machines.

      1. I think what he means is it sound smuch thinner than the 80s-90s FM because it no longer ises FM chips and is basically a VST in a box.

        1. I don’t see why a general purpose chip running a ‘VST in a box’ would sound thinner than a dedicated vintage FM chip. The only difference would probably for the lower bitdepth and samplerate. Which is exactly what I meant to say. But the difference has not much to do with ‘thin’ and ‘not thin’ to my ears.

          1. Because nearly everyone gets complex DSP wrong at some point in the chain-leading to strange filtering problems, that’s why. Thus why the much older, simpler implementations, even with aliasing, often sound (and indeed, are) more spectrally open.

  8. Hey, its FM For Dummies, in a fairly accessible package. If you just want something from the FM family, this is an easy way to get it without tackling a VST or a vintage Yamaha. It sits in a nice sort of middle.

  9. There are lots of options for FM beyond VSTs and vintage Yamaha gear. Having used all the ones below but the Digitone and now the opsix, here’s how I’d rank your FM choices (from worst to best) – oddly this list matches up pretty well with the cost:

    0. VSTs – amazing powerful, but obviously if you’re reading this you want something with physical controls.
    1. Volca FM – powerful, but editing is a little frustrating given how tiny those knobs are. Lack of velocity response when used as a module nerfs it (there are hacks, but…)
    2. Reface DX – great new take on FM editing interfaces. Only held back by only 4 operators, only 8-voice polyphony, mini keys, and the way the voices cut out when changing presets or effects.
    3. Vintage Yamaha – super powerful and you get that vintage gear feels, but horrible to edit, heavy and huge. The smaller ones are usually only 4-op which is a bit limiting.
    4. Opsix and Digitone. Clearly modern FM implementations. Digitone looks like it focuses more on sequencing / percussive sounds. Opsix has more options for other types of sound generation.
    5. I’m probably forgetting some things.

    1. 3. DX11 is quite easy to edit I would say, even from the panel. And you can attach a BCR2000 which gives you direct physical control over all parameters (the DX will choke every now and then though). And it’s a myth that 4-op is not powerful. In fact, I can build you a kingdom with just 2 ops.

  10. So interesting question – Yamaha Reface DX at only $559 AUD, or Korg OpSix at $1199 AUD. Is it worth almost the double the cost of the Yamaha? Yes, it has a better keyboard, and looks to have just as easy to use controls for editing, but is it worth the extra cost over the Yamaha?

  11. Where the Wavestate has clearly a better implementation of wave sequencing then the Kronos, the OP-6 seems rather a slimmed down version of the MOD-7 of the Kronos. So I think the main purpose of this synth is making FM more accessible. Or am I missing something here?

    Otherwise, if you like Korgs FM, but fancy more keys, and you have some more money to spent, you could consider a (second hand) Kronos. The MOD-7 engine will offer everything the OP-6 offers, but you get also completely free patching (instead of fixed algorithms), the use of external audio and samples, import sysex from DX7, multitimbrality, more keys with aftertouch and using its USB ports you can even use USB breath controller like the DX7 (yes, it is possible to import the HARMONICA patch from the DX-7 and use a BC to get the sound of the harmonica solo in Tina Turners “Whats Love got to do with it” …;-).

    Oh, and besides the MOD-7 you will get 8 more different synthesis engines, including wave sequencing (HD1 engine), so you have almost a combined version of Wavestate and OP-6 in one package…

    1. I think you’re right about MOD7. It is weird that none of the reviewers are commenting on the history of this or where the engine comes from. The MOD7 is also in the Nautilus, so it was quite funny to see Sonic Talk where they dismiss the Nautilus as a new wedding band keyboard and then linger over the opsix.

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