Kurzweil XM1 Expression Mate

MIDI can be a creative tool as well as a functional one, and Kurzweil's new stand‑alone ribbon controller is designed to help you exploit its artistic possibilities. Derek Johnson & Debbie Poyser open up a new world of expression.

MIDI Controller messages, which can change subtle and fundamental aspects of sounds in real time, are a gift to those seeking extra depth and interest in their compositions. But few of us use them fully, perhaps firstly because you've got to imagine an effect MIDI Controllers might help achieve, and secondly because tweaking parameters to set it up is fiddly and uncreative. The physical limitations of commonly available tools for playing with MIDI — usually a keyboard and two little wheels, and maybe a handful of knobs — can be a barrier.

To access MIDI's expressive power you need something that looks a bit like a light sabre, along which you can run your finger up and down to wildly produce cascades of note and Controller information. And wouldn't it be great if it also offered three arpeggiators, other control inputs, over 30 ways of using MIDI, and master controller facilities? OK... so you weren't thinking that specifically! Fortunately, Kurzweil were. They've taken the oversized ribbon controller from their K2500 and K2600 workstations, added extra sparkle, and made it available as a stand‑alone device to anyone with MIDI gear and £399 to spare.

What It Is

The Expression Mate MIDI processor comprises a 28‑inch long, 1.5‑inch wide ribbon controller with non‑slip backing (plus a velcro kit for semi‑permanent fixing), and a control box 'brain'. The control box's rear panel hosts a footswitch input, switch/pedal input, breath controller input suitable for a Yamaha BC1, BC2 or BC3, and two sets of merging MIDI I/O. Further potential is offered by two front‑panel buttons which can transmit notes, Program Changes, SysEx strings and other data, as well as starting and stopping the arpeggiators. Every one of the Expression Mate's physical controllers can be set up to transmit any MIDI data and this is done via the control box's rather inscrutable parameter‑access/LCD interface. The one potential physical weak point in the system is the telephone‑style plug that connects the ribbon and brain — not the most robust option.

What It Does

Essentially, the Expression Mate processes MIDI in terms of one or three zones. In the latter case, the ribbon is divided into three sections, each capable of transmitting different MIDI data on different MIDI channels. With it set up as one zone, you can generate high‑resolution pitch‑bend, while with three you can generate notes in one zone, filter cutoff in another, and volume in the third, for instance. There are numerous possible applications: adding expression to sounds easily and intuitively with vibrato and volume swells; creating realistic pitch‑bends and glissandi (a fretless bass for keyboard players!); even playing MIDI notes with the ribbon, using a choice of preset and user scales. The last works well with practice, creating a totally different effect to playing with a keyboard. The Expression Mate could also be a great tool for musicians with limited movement.

The Expression Mate's sophisticated master controller facilities make it ideal to add to a MIDI keyboard lacking such features. They centre around its zones and its ability to assign each a key range, MIDI channel, Program Change number, and transposition amount. If a keyboard can't set up a layer of different sounds, the Expression Mate lets you layer its zones to do the same job. It will also transform Controller data into other data — if your keyboard can't transmit aftertouch, the Expression Mate can transform mod‑wheel data into, say, aftertouch.

The Expression Mate's arpeggiators also work in terms of three zones, so three different arpeggio patterns could play at once in response to note input from different key ranges on your controller keyboard. The arpeggiators can play with note input from the ribbon, or from one of the other arpeggiators (in so‑called 'cascade' mode). Options are comprehensive: there's a wide range of note values, control over note order, key range, note duration, transposition, and more. In addition, you can choose one of eight preset 'rhythms', or create up to 64 rhythms of your own. Tempo can be synchronised to MIDI clock, and you can even sync arpeggios in real time by tapping a footswitch.

Using It

The 31 (overwritable) presets show off the Expression Mate's capabilities. Especially good is the 'Big Strum' preset, which uses the arpeggiators to break the notes of a chord into a huge strum. It doesn't sound like arpeggiation, since each note triggers only when you move your finger along the ribbon. 'Harp Glissando' has a similar feel. Even the simpler presets present ideas for using the ribbon on more mundane tasks, such as controlling volume for super‑smooth fades. The presets are all set up to work with General MIDI, so some tweaking is required to use them with non‑GM instruments.

One preset sorely lacking is a theremin simulator. However, using a single‑zone pitch‑bend preset spreads the available pitch‑bend resolution (potentially over 16,000 steps if a 14‑bit controller is chosen!) across the whole ribbon, allowing very fine pitch control and creating the sweeping glissando effect for theremin impressions. The target sound should have its pitch‑bend range altered from the fairly standard two semitones to 12 or even 24 for best effect. With a suitable patch the results are fabulous; markings along the ribbon even help you find correct note positions, making it easier to play than a real theremin! It's even possible to trill convincingly. Be warned, though, that playing tunes like this generates lots of controller data!

While the ribbon itself is a joy to use, interfacing with the Expression Mate's brain via the control box's 2‑line x 16‑character display makes accessing the dozens of parameters per preset a little irritating. There are a few helpful shortcuts, but the LCD is still a bottleneck.

Physically, some synths will accommodate the ribbon controller perfectly well on the front panel, above the keyboard, but others won't: we couldn't position the ribbon conveniently across our Korg Trinity Pro's panel, since there are no unimpeded flat spaces on the Trinity, so we had to use the ribbon on a desktop.

Buying It?

At first glance, £399 for a MIDI add‑on might seem expensive but if you like the idea of what the Expression Mate can do, you probably won't think it is too much. You should get more than £399‑worth of useful and clever effects, increased expressivity and plain fun from it, as well as squeezing more juice out of synths you already own. If you like to push the boundaries of a keyboard‑based setup, this is a unique system with many applications for studio and stage.