NOVATION XioSynth 25

Novation packs a lot of features into the compact plastic body of the XioSynth analog modeling synthesizer.
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Click here to read Electronic Musician's
comparison of Novation's X-Station and the XioSynth.

Jamming three devices into a tiny case is usually a recipe for frustration, but Novation has done something remarkable. For a few hundred bucks more than a standard USB MIDI controller, the XioSynth 25 gives you rich-sounding virtual analog synthesis, fistfuls of MIDI knobs and buttons, and a 24-bit audio interface — all in a compact keyboard that runs off AC, batteries, or USB power.

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FIG. 1: Combining analog-modeling synthesis, a computer audio interface, and dozens of MIDI controllers, the Novation XioSynth 25 is a terrific value.

The XioSynth (pronounced zy'-oh-synth) contains the same basic synthesis engine as Novation's flagship X-Station but adds sound-shaping features such as filter overdrive and the X-Gator, a rhythmic sound slicer. Of course, Novation did make some adjustments to reach the XioSynth's friendly price point (see the online bonus material at Having reviewed two previous Novation synths for EM (the K-Station and KS4; see and owning a third (the original BassStation), I was excited to try out the company's latest marvel of miniaturization.

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Click here for product specifications for the Novation XioSynth 25

Xio, Silver!

Novation packed a lot of features into the XioSynth's compact plastic body (see Fig. 1). An attractive, 4-page Getting Started guide gets you going quickly, and there's a lot more detail and some handy shortcuts in the nicely illustrated 82-page PDF manual. In between, I highly recommend watching the included DVD tutorials, which walk you through the XioSynth's functions and offer Web links to the artists behind some of its sounds.

Be sure to visit the Novation Web site as well. The USB driver on my disc was outdated and the promised template editor was missing, so I downloaded both from the site. (Note that the XioSynth is USB class compliant, so the driver is not required.) Online, you'll also find an explanation of the clever Preview mode, along with an Answerbase of brief articles addressing common questions. There's even a diagram of the XioSynth modulation matrix, submitted by a customer. I haven't seen this level of support for a new instrument since the original Yamaha Motif came out, and it's very welcome.

Review of the NOVATION KS4 rack synthesizer

Review of the NOVATION K-STATION performance synth

The XioSynth keyboard feels like nothing else I've played. Like other 2-octave keyboards, it uses keys hinged where they disappear into the case rather than farther back, making the black keys hard to press unless you play near their tips. But the XioSynth's white keys also contain substantial weights, which give them surprising heft and make them quiver when they snap back. The strange thing is that the white keys also squish down and seesaw when you press them at the bottom of their travel, as if they were generating Aftertouch (which they don't produce). Nonetheless, I soon grew accustomed to the action and preferred it to the wimpy, switchlike keys on most small keyboards. You can choose among 7 Velocity curves or 120 fixed Velocity values and assign different ones to controller templates (more on those in a moment). The keys transmit Release Velocity as well.

Two octave-shift buttons lengthen the keyboard's range. I was pleased to discover that I could hold a chord with one hand, shift octaves, and solo with the other, a favorite trick (see Web Clip 1). I wish that pressing both buttons simultaneously would reset the octave shift to normal, though.

Real-Time Controllers

Novation's signature joystick and x-y touch pad anchor the control panel's left side. The spring-loaded joystick controls pitch on its x-axis and LFO depth on its y-axis, but you can assign other parameters, such as filter cutoff and delay amount, to the y-axis as well. You can even specify a different bend amount for each of the three oscillators. You can't unhook the y-axis spring, however, as you can on the X-Station.

On the factory patches, the x-y pad is mapped to filter cutoff and resonance. I really liked how rolling my finger slightly produced subtle swells in the sound, while stirring my finger on the pad made dramatic sonic gestures (see Web Clip 2). Unfortunately, tapping the pad makes its output glide to the new value rather than changing immediately, which means you can't play percussive sample-and-hold effects by drumming your fingers.

The control panel furnishes 11 rubberized knobs and buttons. In Synthesizer mode, they control parameters such as oscillator detuning and ADSR settings. In Controller mode, they transmit MIDI Control Changes over USB or the MIDI Out jack. The slick new Hybrid mode routes the knobs and buttons to external devices while the joystick, touch pad, or both control the internal synth. Hybrid mode also lets you use the keyboard to control an external instrument while your sequencer plays the internal synth over USB.

You switch between Synthesizer and Controller mode with a button press. Another button flips the 11 knobs and buttons to a second bank of assignments, giving you a whopping 22 knobs' and 22 buttons' worth of control. The LEDs that indicate which bank is active are very close together, though, so I often found myself adjusting the wrong parameter.

Another button transforms the 11 control buttons into menu triggers. For example, normally button 11 toggles the arpeggiator on or off, but when you press the Menus button, button 11 instead calls up an effects menu in the display. Pressing and holding the Menus button for one second switches the 11 knobs to Audio mode, in which they control settings such as input level, panning, and the balance between the synth and external audio (I had to crack the manual to figure out how to get to that mode). Several of the other buttons do special things when you hold them down or push them twice as well.

Those layers of complexity make navigation confusing. There were several times when I destroyed a sound I was working on by pushing the wrong button because the XioSynth was in a different mode than I expected. Another big annoyance is the white-on-gray labels, which are impossible to read unless the lighting is just right.

Read more of the Electronic Musician review of the Novation XioSynth 25

Xio I/O

For a tiny keyboard, the XioSynth has a surprisingly well-endowed jack panel (see Fig. 2). In addition to the expected stereo line output and headphone jack, you get a sustain pedal jack (sadly missing on the K-Station), and an XLR mic input with switchable phantom power. If your mic supports it, you can set the phantom voltage to values lower than the standard 48V to save battery drain and USB draw. The XLR jack is bolted to the back panel, unlike the jacks on some competing keyboards that attach only to the circuit board. You get dedicated knobs for line and headphone output level.

Because the XioSynth sounds so good, I wanted a MIDI In jack so I could play it as a sound module without a computer. A cord lock for the USB cable would have been reassuring for live use. I also wish the XioSynth had stereo line inputs instead of just a mono one (if that's important for you too, consider the X-Station instead).

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FIG. 2: You can power the XioSynth with batteries, USB, or the included AC adapter. Other connections include MIDI Out, sustain pedal, headphones, left and right line output, mono line input, and XLR mic input with phantom power.

Audio routing is flexible, with dedicated preamp and pan knobs for each input channel. The mic input provides a heroic 70 dB of gain, although hiss starts to creep in around +35 dB or so. You can crank the line input up to +48 dB, which is more than enough to support recording guitar.

For latency-free monitoring, a Monitor knob adjusts the balance between input signal and output from your computer. One of the XioSynth's coolest features is its ability to stream the synth output and the incoming audio over USB simultaneously. Three more knobs control the local synth level, the level sent out over USB, and the panning of the USB synth output. That design made it simple to record a MIDI performance into my sequencer, route the MIDI track back into the XioSynth, and then record the synth's output back into the sequencer as an audio clip.

Architecture 101

The XioSynth's voice architecture is very similar to the K-Station's, which I covered in detail in the November 2002 issue of EM, so I'll hit the highlights here. It has 3 oscillators, each with 17 waveforms — saw, sine, triangle, square/pulse, 4 kinds of noise, and some single-cycle sampled waves such as electric pianos, which are great for adding bell-like harmonics. I did notice some aliasing, though.

The XioSynth is monotimbral and 8-voice polyphonic. Oscillator-warping options include pulse-width, ring, sync, and frequency modulation, giving you scads of ways to animate the sound (see Web Clip 3). The 2 LFOs are fantastically flexible; each offers 32 waveforms and can run in one-shot mode, becoming an extra envelope to complement the amplitude and filter ADSRs (alas, you still can't modulate envelope attack time with Velocity). A Preglide function creates a rudimentary pitch envelope that can punch up note attacks.

The all-important filter section offers lowpass, bandpass, or highpass modes with 2- or 4-pole slopes. Its new Shape and Overdrive parameters add a pleasing distortion (see Web Clip 4). From subtle swirling to throaty leads and booming basses, the XioSynth filter delivers.

Novation is strong on tempo-synced effects, and the new X-Gator supplies a fresh twist. It's a tempo-controlled gate that can mute or attenuate the synthesizer up to 32 times per bar, producing rhythmic pulses (see Web Clip 5). You can change the level of each slice, set the attack and decay of all slices, and even route alternate slices to the left and right outputs. The effect is lighter than arpeggiation, although you can run the XioSynth's multipattern arpeggiator simultaneously for more pizzazz. I was disappointed that the XioSynth doesn't have an LED to indicate when the X-Gator and arpeggiator are running.

Six effects processors round out the sound, and you can run them all at once. The reverb sounds metallic and the phaser is too subtle, but being able to apply all six effects at once is excellent.

Two Novation reps told me they thought the onboard patches were the instrument's highlight. Five dozen patches came from celebrity artists (none of whom I knew). Many patches seemed designed to show off the various distortions, which I found harsh and tiring after a while. Fortunately, the XioSynth is so hands-on that tweaking the sound into something personal is almost automatic.

The factory sound bank offers a hearty helping of synth basses (definitely a strength for the XioSynth), some sawtoothy pads and leads, a side dish of arpeggios and X-Gator effects, and lots of sound effects. You can audition all the sounds online with Novation's XioSynth simulator (see Web Clip 6). I started to like the instrument a lot more after I downloaded and installed some X-Station banks, which showed more variety, including acoustic instrument emulations and the Novation smoothness I'd missed in the parade of fuzz.

Templates in a Teapot

In MIDI controller mode, the XioSynth provides 16 sets of knob and button assignments called templates. The Ableton Live template, for example, maps the first eight knobs on the XioSynth to the first eight volume faders in Live's mixer. Press the Group B button, and the knobs control the effects-send levels for those channels instead. The adjacent buttons mute or solo the channels. In mode B, the last three buttons map to Live's Start, Stop, and Record buttons. I loved the knob control, but I found the XioSynth buttons too small and wiggly to make comfortable transport controls.

When you twist a knob or press a button, the XioSynth displays the target function in its LCD. The knobs have a pickup mode that prevents them from sending data until you rotate them through the current value. Holding down both Effect-select buttons for one second puts the XioSynth in Preview mode, in which the 11 knobs and buttons stop transmitting MIDI completely so you can see what they do. However, the keyboard and left-hand controllers remain active; I could tell that the designers put a lot of thought into how the XioSynth would be used live.

Some of the templates, like the one for Propellerhead Reason (a separate download), require configuration on your computer, dragging files to various places, and enabling checkboxes. The manual does a clear job of walking you through that setup process, but I found that the MIDI mappings for Reason were not useful. Novation provides a downloadable template editor that makes it fairly easy to create new assignments and transmit them to the XioSynth for storage (see Fig. 3). The editor's screen could be much bigger; the labels are cramped and tiny.

It's Off to Work We Go

Five years ago, I praised the compact Novation K-Station in EM, and my ears still perk up whenever its demo songs shuffle around on my stereo. I really like Novation's signature palette of crisp attacks, swirly textures, and juicy filtering. In the XioSynth, the company addressed almost all my wish-list items for the K-Station, added an audio interface and extensive MIDI control, beefed up the bass and filter, and shaved $350 off the price.

The XioSynth is a triple hit, combining three key tools for the computer musician in a flexible, portable instrument with an equally compact price. With a little less miniaturization — simplifying the intertwining modes and restoring the X-Station's input features — it would be a giant home run, even if it cost a couple of hundred bucks more.

David Battino ( is the coauthor of The Art of Digital Music (Backbeat Books, 2004) and the audio and digital music editor for O'Reilly's Digital Media site (


5 = Amazing; as good as it gets with current technology

4 = Clearly above average; very desirable

3 = Good; meets expectations

2 = Somewhat disappointing but usable

1 = Unacceptably flawed

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Click here for product specifications for the Novation XioSynth 25


XioSynth 25
keyboard synthesizer



PROS: Elegantly combines synthesis, audio interfacing, and MIDI control. Up to six simultaneous effects and X-Gator. Battery and USB power. Helpful tutorial DVD. Great price.

CONS: White-on-gray labels and template editor screen are tough to read. No MIDI In. No arpeggiator-on indicator. Touch pad ramps up to tapped value. Multiple modes can be confusing.