QuNexus 2.0 Firmware - new MPE key algorithm and three track step sequencer / arpeggiator

Dear PolyExpression members,

KMI has released a major update to our QuNexus controller. While we are very excited about the new RED enclosure (with a new smooth ABS-Polycarbonate that does away with our previous soft-touch coating), the new 2.0 firmware, which is backwards compatible with legacy units, is something I am particularly proud of.

QuNexus is a 25 key silicon keyboard controller, the keys each sense continuous pressure and “tilt” (equivalent to slide along the Y-Axis). QuNexus has always had “Channel Rotation”, a MIDI implementation that in 2012 was ahead of its time. Using the right settings, you could make QuNexus behave like an MPE controller. With 2.0 we are now fully MPE compliant, using proper manager/member channel settings that can be instantly recalled with factory preset C.

In addition, we have added a three track arpeggiator/step sequencer, and Track 1 will arpeggiate and sequence MPE tilt/pressure data. It’s worth noting that the sequencer tracks are each monophonic, and while this is a limitation of the original QuNexus hardware design (there is only 64k of shared program/data memory in the 8051 microcontroller), we have found that this creative limitation is an interesting and fun take on MPE, and allows us to provide this update to our existing customers as well as new. And while the MPE sequencer playback is monophonic, you can still play live polyphonically while the three tracks are playing back, and all of the mixed MPE member channels will be allocated correctly.

But of most interest to this community will be the new key algorithm. The original 2012 QuNexus tilt algorithm was built around the key “tilt” controlling pitch bend. To engage tilt, you would have to press down and intentionally “grab” the center of the key before moving it. Since then we have learned a lot about playing MPE instruments, and what makes that playback intuitive and “feel” right, and most of the MPE community has standardized around the Y-axis controlling modulation through CC74. So, we have borrowed heavily from our K-Board Pro 4, and rebuilt the QuNexus algorithm from the ground up. The new “tilt” behaves much like the K-Board Pro 4 Y-axis, and is sensitive and instant. You can slide or tap your finger up and down the keys and they will instantly respond. You can see this playability in action in the video below:

One other improvement that we borrowed from K-Board Pro 4 is an updated factory calibration procedure. This is something only available with the new RED units, because it requires us to run the QuNexus through a custom built machine that applies standardized pressure values to the keys and stores the output values into program memory. The new algorithm then takes this data and calibrates the key sensors so that they respond consistently when compared to one another. This process also vastly improves our quality control, so that every new QuNexus RED is guaranteed to respond well and play evenly across all of the keys. We have also added more ways to customize the playability using our editor, allowing you to independently adjust the velocity, pressure, tilt, and bend pad sensitivities.

And on top of all of this, we have lowered the price to $179USD. With the global microchip shortage, some people have seriously questioned this decision, but for now we are going to see how well this is received.

It is hard for a company, especially one as small as we are, to invest so much into an “old” product. This industry is built around product life cycles that typically range from 18-36 months, with new product refreshes that put previous versions at end-of-life with no more updates. It’s a very disposable and trend driven business model, one which requires a constant churning and burning of ideas, instruments, and people. We hope that you see the value in what we have done with QuNexus, and that we are making a statement about our new approach to our customers and products. Since coming on board with KMI in August of 2020, it has been my goal to take us in this direction, and there is much more to come, including new products and designs. But we cannot do this without your support, whether it’s word of mouth or a product purchase.

Legacy users can now download the new 2.0 firmware from our downloads page, and new QuNexus RED are being shipped to dealers as I type these words. We also have RED replacement enclosures available for purchase through the parts page on our website.

I’m happy to answer any questions that you might have.


Eric Bateman
Keith McMillen Instruments


What a spectacular and very clever update! Respect, congrats and thanks to KMI.

The original QuNexus always hit a few very special sweet spots and was rather innovative, as mentioned. Still, I knew that it had more potential that was waiting to be unlocked. It didn’t always function as I had wished, (especially Tilt and the overall key sensitivity, including the pitch bend pad). I don’t want to get into all the gory details, but I can say that this update has completely addressed all of my qualms and so much beyond that. It’s truly impressive how much better the QuNexus functions and feels to play now.

Also, with all of the surprising features and essential fixes/upgrades, that makes even my old QuNexus feel like an entirely new instrument. It’s really worth looking at with a fresh pair of eyes. The new sequencer and arp modes make wonderful use of the LED feedback in a way that I felt I always wanted to use the controller anyway. That sort of thing contributes to making it feel even more like an instrument rather than “just a controller”.

This is definitely the update we were all waiting for and simply so much more than that too. I love the new RED finish and I will most certainly be ordering at least a single new one (for improved sensitivity) and a new RED chassis to upgrade my current QuNexus.

What’s the ETA? :grin:

Edit: It’s worth noting that the new editor also received a very notable improvement (as did the manual), but it’s super that you can do so much on the fly now without needing the editor.


I am very favorably impressed! The whole reason I sold my QuNexus at a loss was because Tilt and Pitch Bend were miserably difficult and inconsistent to use. If it now plays like a K-Board Pro 4, I am SO there. Does the pitch bender work any better now?

Many thanks!

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I just received the new RED hours ago, I will try that and let you know. I still have the old QuNexus to compare against, but it’s already upgraded to the latest firmware, which had thankfully improved it considerably!

The pitch bend pad was the very first thing that we overhauled when the project began, the difference is night and day. It’s easy to engage, it’s balanced, and it will reach the full range of values from -8196 to +8196. There is also a new “Pitch Bend Sensitivity” setting in the editor that adjusts a multiplier in the algorithm before we quantize the data down to 7 bits.

There are also new “Tilt” and “Pressure” sensitivity settings that have the same affect, although the Tilt sensitivity is a little more complex. The old algorithm was designed with pitch bend in mind, and by default you had to intentionally press and wiggle the tilt for it to engage, and it tended to only go up or down. The new Tilt algorithm was designed with modulation (MPE CC74) in mind, and by default it engages immediately and is very sensitive. You can still dial this setting down to make it behave like the old algorithm, but out of the box it will behave like the slide gesture on a KBP4.

The new algorithms apply to both the old black and the new RED hardware, however only the new RED versions use the new factory calibration data method. This is because a new bootloader is required to store the calibration data, and the QuNexus has to be run through our calibration machine.

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Here are some screenshots from the new editor:

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Thank you for the followup! I will buy a RED and try it for myself as soon as I can. But MAN that color is eye-hurting… couldn’t you guys have used the K-Mix blue instead? :grin:

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Did y’all notice there’s a typo on the last screenshot? Sorry… professional copy editor here.

Also, any plans for an iOS version of the Editor?

The screenshot was taken before we fixed that typo, good eye!

For the RED - I promise you it looks great in person, photography can only take you so far when you’re trying to capture LEDs lighting up silicone. Anytime you pick a non-neutral color you potentially annoy someone, but there is too much black and grey in our studios. Another added benefit of us removing the soft touch coating is that you can now paint the enclosure any color you want.

iOS editors - when we reworked the QuNexus editor for 2.0 we laid the groundwork, but how soon we can begin building for iOS all comes down to economics. Let’s hope step sequencing MPE is popular this holiday season.

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Thank you very much for the answers. I am looking forward to trying out the little guy. :slight_smile:


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