The strength of the Alesis Ion is in the depth of its voice programming. No other hardware synth in this price range that can boast three oscillators, dual multimode filters, and a fully functional modulation matrix. Plus, it just plain sounds great. Two compromises keep the price down: The Ion has only 8-note polyphony, and its effects section is very minimal.
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The strength of the Alesis Ion is in the depth of its voice programming. No other hardware synth in this price range that can boast three oscillators, dual multimode filters, and a fully functional modulation matrix. Plus, it just plain sounds great. Two compromises keep the price down: The Ion has only 8-note polyphony, and its effects section is very minimal.

In only a few short years, modeled-analog synths have shaken off their novelty status to become a mature technology. Europe has built up a dominant position in this field: the formidable reputations of Novation (the United Kingdom), Access (Germany), and Clavia (Sweden) have left even the Japanese giants scrambling. So it must have taken a bit of courage for an American manufacturer to dive into the modeled-analog shark tank.

But Alesis was undaunted. The company has been building keyboards for years, of course. It started with the popular QuadraSynth-series keyboards, which use sample playback. More recently, the Andromeda, a high-end real analog synth, has garnered plenty of attention (and an EM Editors' Choice Award). The Ion is another story entirely. Its under-$1,000 price tag puts it in competition with the more affordable European synths, and its “analog” tones, like theirs, are generated using digital circuits.

The strength of the Ion is in the depth of its voice programming. I'm not aware of any other hardware synth in this price range that has three oscillators, dual multimode filters, and a fully functional modulation matrix. What's more, it just plain sounds great. Two compromises keep the price down: The Ion has only 8-note polyphony, and its effects section is very minimal. True, the original Clavia Nord Lead sold very well with no effects to speak of. But that was then; this is now. If those limitations don't dampen your enthusiasm, keep reading, because the Ion has a lot to get excited about.


On taking the Ion out of the box, my first impression was that the buttons on the panel are too small, as is the lettering beside the buttons and knobs. The knobs, at least, are large and solid feeling, with a nice-feeling rubberized surface. The steel chassis is slab shaped, not contoured into a wedge like most keyboards, and the boxy profile is emphasized by the cheap-looking red plastic end pieces (see Fig. 1).

Around back are main and aux audio outputs (both stereo), audio inputs (also stereo), a headphone jack, two pedal jacks, and standard MIDI connectors (see Fig. 2). The jacks are labeled along the edge of the top panel, a detail that too many manufacturers omit. The audio inputs can be used with the Ion's vocoder, or you can pass the external signal through its filter and effects. Again, these are not features you see in too many under-$1,000 synthesizers.

The keyboard is only four octaves in length and does not sense Aftertouch, though it senses Release Velocity, which is not a feature you see every day. The action is so light that it feels a bit spongy. At first I didn't care for the action, but once I got used to it I didn't mind it at all. Octave up and down buttons on the panel expand the Ion's total range to ten octaves, and having two mod wheels in addition to the pitch-bend wheel more than makes up for the lack of Aftertouch. The wheels, which are translucent, have the same nonslip surface as the knobs. When moved away from the zero position, they emit red light, the intensity of which increases as the wheel moves further away from zero.

The Ion is equipped with a hi-res LCD, below which are five navigation buttons. You don't see such a friendly interface on many keyboards in this price range. When the synth is powered up, the borders of the tiny buttons glow in either red or green, which makes it easier to keep track of what's going on. Practically every module has its own edit button, which brings up a menu containing anywhere from two to six pages of parameters. This system effectively minimizes the need for prowling around in submenus: no parameter is more than four or five button presses away.

With the parameters that have dedicated knobs, touching the knob immediately brings up the LCD page where the knob's parameter is displayed. This convenience feature becomes problematic, however, if a knob has “data incontinence,” meaning it occasionally transmits a value even though you're not touching it. This was the case with the oscillator 2 pitch knob on the unit I had for review.

The knobs are free rotating, so they always start from the current value of the parameter when you move them: there's never a jump in the sound. That is definitely the right design for a synth that's meant to be played. The only knob that pegs at the left and right extremes, appropriately, is the bright red master-volume knob.

The Ion has four program-memory banks with 128 programs each. By default, one bank is user-programmable, and the other three are presets. A Global menu option allows you to disable the write protection of the other three banks for a total of 512 possible user locations. There's also a bank of 64 programmable multitimbral setups. The instrument is 4-part multitimbral, and individual parts within the multisetups can be muted and unmuted in performance with one button press. Also included is an arpeggiator with a variety of rhythm presets.


The sound set included in the Ion has all of the expected food groups — basses, leads, comps and pads, filter sweeps, assorted vintage-instrument simulations, electronic percussion, and special effects. At the top of each program bank are patches that use the arpeggiator. These run mostly to techno-style synth riffs, thudding kicks, and sizzling hats. In about half of the setups, two or three rhythmic programs are assigned to the left half of the keyboard with a pad or lead sound in the right hand. The rest are mostly “gig splits.”

Gentle pads such as Dutch Choir and moody string-and-vocal timbres like Vindicarum and Rusty Strings are bound to be useful. Velocity Strings responds to light keyboard caresses with a slow attack and release, and to harder playing with a tighter envelope shape. The brassy TouchPhaseComp, SteelAndBrass, and J Brass are more aggressive, but Fast n Brassy and Owbercomper are on the thin, tweezy side.

Some of my favorite patches, such as Laryngitis and the eerily unstable Howling Dogs, use the Ion's dual filters to create vocal-like formants. But for unpredictability, Bromide takes the cake: metallic noises skitter up and down the frequency spectrum, subsiding to a low rumble or rising to a screech at random, and sometimes responding to the mod wheels while at other times ignoring them entirely.

Many of the basses are wide open, filling up a lot of the frequency spectrum. In the raspy Adrastea and the snappy Old Favorite, this approach worked well, but patches such as Cellar Bass, Parabola Bass, and Big Bass Pedal are a little loose for my taste. JacoInTheBox is tight, and the filter responds well to Velocity. This patch would have benefited from a rich chorus effect, though, at least if the idea was to evoke Jaco Pastorius.

While unlikely to fool the connoisseur, the Hammondish Stops On MW2 has a satisfying smoky flavor, and the second mod wheel does indeed switch between three different drawbar settings. SynWurly doesn't have the bite or honk of a real Wurlitzer electric piano, but it's warm and tubby. ItsJamaicaMon is a decent stab at a steel drum. ArEmEye Piano has a little of the sizzly buzz of the RMI, but both this patch and 60's Organ are rendered less realistic by the too enthusiastic use of filter envelopes. Classic synth patches like Jump, Cars Sync, WontGetFooled, and Lucky PortaMW2 evoke hit records of yesteryear.


The range of sounds you can achieve with the Ion is simply vast. You could easily pay twice as much for a synth that doesn't have this level of programmability. A partial list of unexpectedly cool features would have to include two types of oscillator sync, oscillator waveshaping, loopable envelope generators, extremely flexible routings for both audio signals and modulation, and more than a dozen filter types. Without trying to cover every single feature, let's hit the highlights.


The three oscillators are functionally identical except for their front-panel layout and the FM and sync routings. Each has a choice of a sine, tri/saw, or pulse waveform, and all three waveforms can be deformed by waveshaping. In the case of the pulse wave, this produces pulse-width modulation. I wouldn't have minded if the thinnest possible pulse wave had been a little thinner, but I'm willing to trade that for the shapable sine wave, which has a nice rounded tone that's quite distinct from a triangle wave.

Each oscillator has a dedicated knob for waveshaping, plus octave up and down buttons. Coarse- and fine-tuning for oscillators 2 and 3 is handled with a knob, but you have to delve into a menu to change the tuning of oscillator 1. That is because the panel space is taken up by an FM amount knob.

Three FM signal routings are provided: 2 into 1, 3 into 2 into 1 (stacked), and 3 and 2 both into 1 (parallel). The main limitation of this setup is that there's only one FM-amount parameter. It can be controlled by any modulation source, however, so there are a lot of possibilities. Linear FM operates in the familiar DX7 style, while exponential FM changes the fundamental pitch, producing thick, clangorous timbres. The ring modulator, which always uses oscillators 1 and 2 as inputs, also produces clangorous tones, but it has a gentler sound, as well as its own input to the prefilter mixer.

Two other details are worth noting: pitch-bend depth is separately programmable for each oscillator, a feature that works nicely in combination with the distortion effect, because it lets you add thickness to pitch bends. And you can choose whether to sync only oscillator 2 or both 2 and 3 to oscillator 1. The soft-sync option produces thicker, more unstable tones than hard sync.

Ion Specifications Sound Enginemodeled analogAudio Inputs(2) balanced ¼" line levelAudio Outputs(4) balanced ¼" line level; (1) ¼" stereo headphoneMIDI Connectors(1) In, (1) Out, (1) ThruKeyboard49-note unweighted, Velocity and Release-Velocity sensitivePolyphony8 notesMultitimbral Parts4Program Memory384 ROM locations, 128 RAMSetup Memory512 RAM locationsOscillators(3): soft and hard sync, linear and exponential FM, ring modulation; (3) waveforms, all with waveshape modulationAdditional Sound Sourcesnoise (2 types), external audio inputFilters(2) resonant multimode, configurable in series, parallel, or blendEnvelope Generators(3) ADSR with slope time; loopableLFOs(2) with tempo sync, (4) waveforms in 0- and 90-degree phase-output versions, all available simultaneously; separate sample-and-hold with output smoothing and selectable inputEffectsvoice effects: distortion (4 types) or dynamics (2 types); output effects: flanging (2 types), phasing (2 types), chorus, slapback echo, vocoderArpeggiator(31) preset rhythms plus random, pattern-length control, (6) order modes, tempo multiplierControllers(31) knobs, (3) left-hand wheelsPedal Inputs(1) sustain and (1) expression, both assignable in modulation matrixDimensions31.0" (W) × 3.0" (H, incl. knobs) × 12.5" (D)Weight20 lb.


Each filter has its own cutoff, resonance, and envelope-amount knobs. Keyboard tracking is handled in the edit menu. Although Alesis cleverly avoided trademark issues by referring to various filter types as mg, ob, rp, tb, and jp, the references to Moog, Oberheim, ARP, and two vintage Roland models are not hard to decipher. The 2-pole ob filter is available in lowpass, bandpass, or highpass mode. In addition, there's an 8-pole lowpass, a 6-pole bandpass, a dual bandpass in which the bands are spaced an octave apart, three vocal-formant modes, two comb-filter modes, an adjustable-width bandpass, and a mode called Phase Warp, which connects eight allpass filters in series.

The Ion has prefilter and postfilter mixers. In the prefilter mixer you can set the levels of the three oscillators, the ring modulator, an external signal, and the noise generator. The last two share a level knob, but both inputs can be active at once. By diving into the Edit menu you can also pan each signal between the two filter inputs and adjust the amount of signal from filter 1 that's being sent to filter 2. In the postfilter mixer you can set the level and panning of each filter at the voice output, and do the same for a signal coming from the prefilter mixer. This unfiltered signal can come from any single oscillator, from the combined input to either filter, and so on.

When the output of filter 1 is turned down in the postfilter mixer and the 1-into-2 routing is turned up in the prefilter mixer, the two filters are in series. Yet at the same time, one oscillator might pass through both filters while another passes only through filter 2 and another reaches the output unfiltered. When you consider that each of the mixing parameters can be controlled in real time from any of a variety of modulation sources, it's hard to imagine any sort of filter configuration that's beyond the reach of the Ion.

Envelopes and LFOs

The Ion's three envelope generators are ADSRs with an added sustain-time parameter. When the latter is set to hold, a standard ADSR configuration results, but if sustain time has a finite value, the envelope will proceed through the decay and sustain segments and end up back at zero. The attack, decay, and release segments can all have their own choice of a positive-exponential, negative-exponential, or linear shape. The Velocity-response amount is programmable within each envelope — no need to use up mod-matrix routings on it.

But that's only the start of the fun. Each envelope can either respond to or ignore the sustain pedal. And there are three loop modes, called Decay, Hold, and Zero. These interact in various ways with two other mode switches, the reset/legato switch and the release/freerun switch. For details, reading the manual and experimenting are recommended. It's not difficult to set up an Ion patch that will play an eight-note plucked rhythm forever, even when the arpeggiator is not turned on.

Though the three envelopes are identified as being for pitch/modulation, filter, and amplitude, all are available as general-purpose modulation sources. If necessary, you can assign one envelope to filter 1 cutoff and another to filter 2. The only limitation at this point is that the envelope-amount knob won't be reassigned for the filter that doesn't use the filter envelope.

The two LFOs have the usual parameters, including the ability to sync to an external clock. They have several retrigger modes, not just monophonic and polyphonic, and each of them has its own amplitude-control input, which uses mod wheel 1 as a source. Again, this eliminates the need to use up one of the 12 mod-matrix routings for this common type of modulation.

Far less usual — indeed, unique in an instrument in this price range — is the inclusion of a sample-and-hold processor that's entirely separate from the LFOs. It isn't limited to sampling noise, either: it can sample an LFO, an envelope, a wheel, incoming MIDI controller data, or various other things. In addition, the output can be either stepped or smoothed by some percentage.

Modulation routings

Using the Ion's 12 general-purpose modulation routings, you can modulate just about any parameter in the instrument (excluding switch values, such as Filter mode). More than 30 internal modulation sources are available, and it's noteworthy that all of the LFO waveforms are available simultaneously. MIDI Channel Pressure, Aftertouch, and Control Change types 1 through 119 can also be selected as sources.

The one thing I missed in this section of the instrument was the ability to modulate the depth of one routing from another routing, a useful feature found in the E-mu Proteus 2000 series. LFO and envelope-output amplitudes can be modulated, however, which helps overcome the limitation. Also, the time value of each segment of each envelope can be modulated individually, which adds a great deal of expressive control.

The modulation section of the Ion includes a tracking generator. This accepts most of the same inputs as the modulation routings and allows you to program a multisegment response curve, which can then be used as a modulation source. The tracking generator can define either 24 or 32 points, your choice. With some inputs, such as the mod wheel, half of the range will be wasted, because it responds to inputs whose value is below zero, but other inputs (such as the pitch wheel and the LFOs) can drop below zero, allowing the full tracking generator to be used. If you've ever wished for an LFO waveform with a little bump in it, the tracking generator will take care of you. It has many other uses as well, from nonlinear filter tracking of the keyboard to setting up mod-wheel movements that change the timbre in only one portion of the wheel's travel.


Given the no-compromise power of the Ion's voice architecture, its skimpy effects section comes as a bit of a surprise. The distortion/dynamics processor is polyphonic; that is, it's applied separately to each of the instrument's eight voices. The chorus/slapback effect is applied to the mixed output of all the voices, but it's stereo, not mono: you can pan one filter output hard left and the other hard right, and you'll hear the chosen effect on both signals.

The distortion/dynamics section has four distortion algorithms (tube overdrive, tube amp, distortion, and fuzz), as well as a compressor and a limiter. Because it's polyphonic, the distortion becomes noticeable mainly when two or three oscillators are detuned from one another. The drive level can be cranked up and the program-output level attenuated to compensate, but that's it for programming. An option to switch to monophonic operation would have been welcome.

The chorus section provides two phaser algorithms, two flangers, a chorus, and a slapback echo with a maximum delay time of 80 ms, which is extremely skimpy. The chorus isn't as lush as I'd like, but the phaser and flanger sound crisp and lively when the regeneration is cranked up. In addition, there's a 40-band vocoder algorithm.

What's odd about this setup is that a vocoder is a fairly computation-intensive effect. If there's enough DSP for vocoding, you'd think there would be enough for a decent reverb. And given that the vocoder has 40 parallel bandpass filters, why is there no graphic or parametric EQ among the effects?


Because the Ion is always in multitimbral mode, even if only one part of the multi is active, MIDI settings such as channel and local off are found not in the global area but in the part-edit pages. One advantage of this is that you can easily create a setup in which an external sequencer plays the Ion on one channel while a second channel is active only from the keyboard, neither transmitting nor receiving MIDI data.

The Ion's knobs can be instructed to send MIDI, allowing you to record a knob-twiddling performance in a sequencer. Knob data is sent in the form of NRPN (Non-Registered Parameter Number) messages. This will make it impractical to edit your knob-sweeps in the sequencer. If you need to edit, a better method would be to reassign mod wheel 2 temporarily to an appropriate CC number and assign that CC number to the desired parameter in the modulation matrix.

While reviewing the Ion, I upgraded the firmware from 1.0 to 1.02 by downloading an SysEx file from the Alesis Web site and transmitting it to the Ion from Cakewalk Sonar. The process went without a hitch.


For younger musicians who are just getting started with synthesis, but who know they're going to be serious about it, the Ion would be a terrific choice. No other hardware instrument in its price range has this amount of sound-programming power. I'm betting the Ion will also find a home in secondary-school and community-college sound labs. Teaching synthesis with this instrument would be downright fun for both instructors and students, because it will do so much.

The limited polyphony, the weak effects section, and the flimsy-feeling keyboard may discourage some professionals. For studio work, on the other hand, none of those factors is exactly a deal breaker. If you need a versatile tone module that can not only handle bass, pads, and special effects but encourages inspired sound design, the Ion is worth taking very seriously.

Jim Aikinis the author of Power Tools for Synthesizer Programming (Backbeat Books, 2004). You can visit him online



virtual-analog synthesizer


PROS: Extremely versatile voice architecture, including dual multimode filters, three loopable envelopes, and a modulation matrix. Thirty infinite-rotation knobs, three left-hand wheels. High-resolution LCD.

CONS: Weak effects section. Limited polyphony. Flimsy-feeling keyboard.


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