Recording - December 2013 - 62

B Y M I K E M E T L AY

Keith McMillen Instruments QuNexus
An unusual portable controller opens new performance possibilities

The QuNexus is a new USB and CV
controller from Keith McMillen Instruments.
KMI is known for unusual approaches to
controller design; previous releases include
the SoftStep, a pedalboard-style controller
where every "footswitch" is actually a pressure-sensitive 3D control joystick, and the
QuNeo, an iPad-sized control surface with
a highly customizable array of backlit
pads, touchstrips, and other controls. The
QuNexus is KMI's approach to the keyboard controller form factor that was first
popularized with the Korg nanoKEY: a 2octave controller, relatively flat, that can
easily slip into a laptop bag.
The QuNexus is 12.8 x 3.3 x 0.43 inches in size and weighs about 12 ounces. Its
primary controls are an array of 25 backlit
pads in the layout of a 2-octave piano keyboard; there are also five buttons (a Shift key
and four marked A/B/C/D), Octave up and
down buttons, and an oblong Pitch control
pad. Note that these pads do not move like
those of a conventional keyboard; the
QuNexus has no moving parts, which may
contribute to a sturdier design. The case is
solidly built and resists flexing, a good sign.
Many ins, many outs
There are two USB connectors: a microB connector on the left end for connection
to a computer, and a mini-B connector on
the right that connects to the KMI MIDI
Expander. This add-on device allows the
QuNexus to function as a MIDI interface
as well as a controller, and will power it for
use away from a computer if desired. You
can also use the QuNexus as a straight CV
controller by powering it from a conventional USB wall-wart power supply.
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RECORDING December 2013

There are two TRRS minijacks and two
TRS minijacks on the ends of the
QuNexus. These offer, between them,
two Control Voltage inputs that can be
used by a sustain pedal and an expression pedal or accept CVs from a modular
synthesizer or compatible effects processor, plus four outputs, three CVs and one
Gate. This lets the QuNexus act as a flexible MIDI/CV converter as well as a control surface. The manuals carefully
explain the voltage ranges expected by
and produced by the QuNexus, and
even describe a number of simple homebrew circuits that allow users to convert
bipolar CV sources into something the
QuNexus can understand, or permit the
keyboard to work with two expression
pedals or two sustain pedals. Tinkerers
will love working with this keyboard!
When are keys not keys?
The keyboard itself consists of 25 backlit pads that respond not only to being
played in a conventional manner (sending MIDI Notes and Velocity data) but
also to Pressure and Tilt, which is a signal
sent depending on whether you rock your
finger forward or backward on the pad.
In the main Keyboard Layer (more about
Layers below), Tilt is only sent by one key
at a time, usually the last key played.
The manual doesn't (yet) explain how best
to use Tilt; for best results, hit the key at the
center, press down firmly (this will also send
Pressure data if you've activated it), and then
press your finger forward on the key as if trying to push up a stuck fader, or pull toward
yourself as if trying to pull one down. Your fingertip doesn't actually move, but the pushing

or pulling activates Tilt data. It takes quite a bit
of practice, but it works as advertised.
Four front-panel buttons allow you to turn
Velocity, Pressure, and Tilt sensitivity on and
off, and to switch the pads between
momentary and toggle operation, in which
you touch a pad to play a note, and touch
it again to turn it off. Toggling can let you
latch multiple notes at once, or operate in
Legato mode, where selecting a new note
turns off the previous one.
This allows a lot of expressive capability over the whole keyboard or for individual pads, as the pads (unlike the keys
on a conventional keyboard controller)
are capable of individually sensing and
sending Pressure data; this lets you control hardware and software synths that
understand Polyphonic Aftertouch (Key
Pressure) data, a very expressive feature
that's been almost completely absent from
MIDI keyboards since the 1990s. This is
especially nice when using the QuNexus
over USB to an Apple iOS device via the
Camera Connection Kit; the pads let you
perform poly aftertouch tricks common to
apps like Moog's Animoog synthesizer
with actual tactile pressure rather than
sliding your fingers around on the screen.
This sort of polyphonic data transmission
can be further simulated using Channel
Rotation, in which every note you play
sends data on a different MIDI Channel.
Imagine being able to polyphonically bend
pitch on every note with pressure, for steelguitar licks!
Part of a system
The QuNexus is seen by your DAW as
having three sets of MIDI In and Out ports;
Recording - December 2013

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