New Gear Review: Opsix (Altered FM Synthesizer) by Korg

“The opsix represents a new and expansive reimagination of classic digital synthesis.”

All the way back at NAMM 2020, the Korg booth had many synthheads’ hearts aflutter.

Funnily enough, it was for an instrument that they couldn’t hear yet, or even touch, as the sole prototype was displayed in a translucent case, at an angle, as if to highlight its angular, sleek design.

That synthesizer was the Korg Opsix, and though it arrived in slightly altered form over 18 months later, many were still clamoring for it.

The Opsix is Korg’s first FM synth since the Volca FM and is said to build on some of the lessons learned from that instrument. Importantly, the Opsix is called an “Altered FM” synth, as it can go beyond what previous FM synths could do.

So, how does the Opsix live up to the initial hype now that it’s seen some time in the hands of many qualified users? Let’s dig in and find out.

Features

The 32-voice Opsix comes in a lightweight plastic case with a 37-key keybed. It’s a great length for sitting on your desk without taking up the entirety of the surface while still allowing for two-handed playing.

The rear of the instrument features a stereo output on the traditional ¼” jacks, a headphone output (which mirrors the main out), a USB port for MIDI and firmware updates, a sustain pedal input, and the usual full-size MIDI ports, as well as the power adapter input port.

A good portion of the front panel is taken up by the Operator Mixer, which has six knobs sitting atop six fairly long faders. The knobs control Oscillator ratio by default, whereas the faders are set to control Oscillator level.

In typical FM fashion, you can choose through an assortment of algorithms that alter the arrangement of carriers to operators, but it’s also possible to create user algorithms that are only limited by your imagination.

Calling the Opsix just an FM synth would be a faux pas, as in reality, Korg have included five synthesis methods under the hood. The front panel shows each clearly in case a visual reference is needed, much like the classic MS2000.

Along with FM, there are Ring Mod, Filter, Filter FM, and Wave Folder modes, each with their own assortment of presets. Speaking of presets, there’s a gigantic range to choose from and the breadth of sounds is quite astounding. Korg have done a really terrific job showing off what the Opsix can do.

There are eleven filter types to choose from, with all the usual suspects being included, as well as Korg specific models of the MS20 and Polysix filters. These sound great and each have their own characteristics, with the MS20 filters sounding just a touch more aggressive, as you’d expect.

Three LFOs and three Envelope Generators are included per patch, so you aren’t short of modulation options. As you’d expect, almost all of the operator characteristics can be modulated.

Further down the signal chain are three effect slots, of which you have 30 options to choose from. Again, Korg have given you a lot of variety, even including things like a guitar amp simulator, auto wah, and BPM-matched phaser and flanger effects. Each effect comes with its own custom parameters.

Korg also recently announced a new 2.0 firmware update that adds a new Effect operator mode, pink and blue waveforms to the Noise source, improved aftertouch routing, and an additional 100 new preset sounds.

In Use

So, how does it all sound when the chips are on the table? Well, the Opsix synth engine is very responsive to dynamics; so simply playing through the presets is a joy, as it feels like there are several timbres available at once.

The large pitch and mod wheels are fun to grab and very easy to tweak, as are the dedicated octave up and down buttons, which are always within reach. Deep pads, rumbly basses, smooth glassy bells, electric pianos? Check, check and check. The Opsix can handle those bread and butter FM sounds with aplomb but it’s also not afraid to get weird if pushed.

In general, the front panel of the Opsix shows great ergonomics, as it felt fun to explore without feeling overwhelming with options. The operator mixer is a lot of fun to play with during performance, as this ‘mixer’ feature is completely new with any hardware FM synths I’ve seen.

The Data knob / macro system here works well given that there are only six main pages to sort through. Pressing shift accesses six additional settings per patch, such as arpeggio settings, sequencer range, swing amounts, and more. There’s also an incredibly handy Virtual Patching system that allows you to route a number of destinations (including keyboard notes) to almost any mapping in the synth engine. Incredibly complex patches can result from this.

The 16-step sequencer is similar to the sequencer on the Korg monologue where each step can be turned off individually with its respective button. This makes for a very dynamic way to perform with the step sequencer as you can also play over top of whatever sequence you’ve got going. The sequencer has a fair number of options as well. You can control the direction, shuffle, and musical note value, among other specs.

To Be Critical

There wasn’t much to be critical of regarding the Opsix. However, the keybed did feel a bit flimsy given the sonic power here. Compared to the Fatar keybed of such offerings like the Prophet, you’d wish Korg would offer a more ‘premium’ keybed option.

Similarly, the input and output jacks are a bit hard to get to given the recessed panel. Finally, there’s no way to sort or filter through presets. Given the breadth of what’s available, it’s a shame because it makes it a bit of a hassle to quickly locate your favorite preset again.

Summing it Up

All in all, there’s a lot to love about the Korg Opsix. Korg put together an impressive package in a small 37-key instrument that not only tackles a plethora of FM tones but can form the basis of your entire sound studio.

The number of hands-on controls on the front panel makes using the Opsix as much fun as it sounds great. With the newest update, there’s even more to love and it also shows that Korg cares about the longevity of this product. You can expect to see the Opsix as a favorite in many studios for years to come.

Leo Maymind is a producer, DJ, and writer living in Los Angeles, CA. He is obsessed with sound, and you can reach him at lmaymind@gmail.com.

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