Alesis Andromeda A6 Analog Synthesizer

Occasionally, a musical-instrument manufacturer introduces a product that marks a real departure from its usual fare, an instrument that elevates the

Occasionally, a musical-instrument manufacturer introduces a product that marks a real departure from its usual fare, an instrument that elevates the company into a higher echelon of quality. For Alesis, the Andromeda A6 might be that instrument.

Although several ambitious analog synthesizers have been produced in recent years, people no longer live in a climate where fully analog dinosaurs dominate the landscape. The expense and effort involved in designing and producing a powerful analog synth are considerable, even daunting, in today's economic climate. Consequently, it is particularly noteworthy when the design process leads to a product that the company is able to manufacture and sell successfully.

The Alesis Andromeda A6 is a fully programmable 16-voice synthesizer with 32 real analog oscillators, two independent multimode filters, and extensive hands-on controls (see Fig. 1). The Pitch-Bend wheel, Modulation wheel, and ribbon controller are completely assignable to any modulation destination or MIDI continuous controller. Thanks to a sequencer that emulates analog sequencers of the 1970s, each Program can store its own 16-step sequence of three simultaneous modulation signals and note triggers. Onboard effects provide analog distortion and digital signal processing. Two audio inputs let you route external sound sources through the Alesis Andromeda A6's filters.

The Alesis Andromeda comes with a well-written manual that covers everything you need to know to operate it, including an introduction to analog synthesis. The manual is definitely one of the better ones I've read recently for an instrument of the A6's depth.

The Alesis Andromeda A6 is a complex instrument with a tremendous number of features, and I don't have enough space to cover them all in detail. Instead, I've tried to touch on the essentials and especially the aspects that best illustrate the instrument's design and feel.


The Alesis Andromeda A6's design is definitely hardware intensive. For anyone who grew up with classic synths such as the Sequential Circuits Prophet-5 or the Oberheim OB series, the A6 is a happy return to the familiar panorama of knobs and buttons. Most of the 72 knobs and 144 buttons are dedicated to specific functions, except for eight soft knobs whose functions change depending on what's displayed on the LCD (see Fig. 2). Beneath those are eight soft buttons that are similarly software assignable.

At the center of the Alesis Andromeda A6's front panel is the large backlit LCD that serves as the main control area. When you adjust an A6 knob, the LCD displays that parameter's values by default; you can, however, defeat that function using the Lock Display function. In addition to being able to see the current state of all or most parameters related to an A6 function at a glance, you can adjust them numerically (and thus with greater precision).

On the rear panel, eight ¼-inch TRS jacks provide individual outputs for all 16 voices by putting odd-numbered voices on the tip and even-numbered voices on the ring (see Fig. 3). A pair of main outputs is supplemented by two aux outs and a stereo headphone jack. Two CV Inputs allow external modulation of any oscillator destination and filter cutoff or resonance. Three Filter Audio Inputs facilitate processing external audio through the Alesis Andromeda A6's filters. The Alesis Andromeda A6 also provides jacks for a CV footpedal, an assignable footswitch, and a sustain pedal, as well as a PC Card slot for external data storage.


The Alesis Andromeda A6's two basic modes are Program and Mix. A Program stores a complete set of synthesis and effects parameters in one of 128 User Program locations. In addition, two ROM Preset banks contain 128 Programs each.

A Mix is a combination of as many as 16 Programs set up as layers or splits. Mixes can contain as many Mix Channels (Andromeda's term for Programs inside a Mix) as desired, but they must share the Alesis Andromeda A6's total 16-note polyphony. Mix mode provides control over transposition, level, panning, and controller enable for each Mix Channel. Each Mix Channel can receive on its own MIDI channel for multitimbral operation. Two Mix banks, one Preset and one User, each provide 128 locations.

The fastest way to recall Programs is with the Program Group (bank select) and Program Number buttons located just above the ribbon controller. You can also press the Program button and select a Bank and Program with the soft knobs located under the LCD. The Alesis Andromeda A6 lists Programs and Mixes one at a time or in a directory that lists ten at a time. You can store User Programs and Mixes internally or on PC Cards through a rear-panel slot.


Once you're comfortable with the Alesis Andromeda A6, it quickly becomes clear that it was designed by knowledgeable people who wanted to avoid the interface pitfalls of previous analog monsters. The most obvious example is the liberal use of dedicated function buttons surrounding nearly every knob. Despite the front panel's density, anyone with analog synth-programming experience should understand most of the controls, making the instrument easy to get used to.

When you press the View or Mod buttons, for example, the display shows the relevant parameter's value or modulation routing, respectively. Speaking from experience with modulation-intensive synths such as the Oberheim Xpander and the Voyetra Eight, those two buttons will make many synthesists happy; there's no confusion about which source is modulating which destination. Any of the Alesis Andromeda A6's 79 mod sources can modulate just about anything else.

In addition to Pitch-Bend and Modulation wheels, the Andromeda features a large old-style ribbon controller that you can assign to manage almost any parameter in real time. The ribbon operates as both a single and a split modulation source, so you can use its entire length or its left and right halves to control several parameters simultaneously, yielding a tremendous range of possibilities. For example, I set up the ribbon to regulate both filter frequencies, modulating one positively and the other negatively, while also controlling the level of the bandpass filter.

On the front panel's left side are the Clock section, which contains controls for the arpeggiator and sequencer, and the master volume and tuning section, which includes an Auto Tune button. In addition to tuning the oscillators, Auto Tune calibrates oscillator pulse widths and filter frequencies. The LCD shows Auto Tune's progress and results for each oscillator and filter. You can't play while autotuning (just like the old days!), so be sure the Alesis Andromeda A6 has enough warm-up time for you to tune it before going onstage.

Also on the left are controls for Keyboard mode. One Keyboard mode, Unison X, lets you specify how many voices will be ganged together to play in unison. The number can range from 2 to all 16 voices, allowing plenty of flexibility for fattening up patches while retaining as much or as little polyphony as desired. Switching on Unison X doesn't simply eat up all the voices and reduce the Alesis Andromeda A6 to a huge mono synth unless you want it to. If you do want monophonic operation, the Poly/Mono switch handles that.

Farther to the right, the Alesis Andromeda A6's main programming area contains three LFOs and a sample-and-hold generator, which can be routed to practically any destination and modulated by another source. The LFOs can run freely or be triggered by any mod source. You can also sync the LFOs to the internal clock or external MIDI Clock.

The Alesis Andromeda A6's comprehensive MIDI implementation lets all of the front-panel controls send and receive Non-Registered Parameter changes. The ribbon sends a pair of controller numbers, which you can specify on the CC Map page in the Global section. System Exclusive support allows you to send Programs and Mixes to a librarian program either singly or in bulk dumps.


The Alesis Andromeda A6's conventional analog oscillators offer pulse, sawtooth, triangle, and sine waveforms. Although the pulse button is labeled Sqr, you can vary its width with the Pulse Width knob or any modulation source. The Sawtooth button toggles the waveform between positive and negative polarity when pressed. Each oscillator's Semitone knob is accompanied by an Octave LED and tuning knobs labeled Cents and Fine. In addition to three modulation routings for each oscillator, Oscillator 1 has a knob to adjust FM depth from Oscillator 2, and Oscillator 2 has a knob to adjust modulation depth from Envelope 1.

Directly to the right of the Oscillator section is the Pre-Filter Mix area, where you can balance the levels of the oscillators, ring modulator, and Noise/External inputs before they arrive at the Alesis Andromeda A6's Filter section. Also in that section is the Filter Feedback parameter, which routes the filter's output back into the Pre-Filter Mix module. When Filter Feedback is turned on, the Noise/External knob becomes a filter feedback level control. That feature is a personal favorite because it lets me raise the general level of grit across the board.

The Alesis Andromeda A6's noise generator provides white, pink, and red noise options, selected by toggling between four LEDs with a selector button. The fourth position, External, is for routing external audio sources through the A6's filters.

To the right of the LCD is the Alesis Andromeda A6's comprehensive filter section, which contains two independent filters. Filter 1 is an Oberheim-style 2-pole multimode filter, and Filter 2 is a 4-pole lowpass filter with a Moog-influenced design. In addition to three simultaneous modulation routings for controlling each filter's frequency, knobs for Resonance, Env 2 Amount, and Key Track are clustered around each filter's Freq knob.

You can select from three filter routings or bypass Filter 2 entirely. Mix puts the two filters in parallel with each other. Notch sends the sum of Filter 1's lowpass and highpass sections to Filter 2 for further lowpass filtering. In BP, Filter 1's bandpass output is sent to Filter 2.

The most powerful aspect of the Andromeda A6's filters (aside from there being two of them) is that all filtering modes are available simultaneously and can be mixed using the Post-Filter Mix section. Five dedicated level knobs — Filter 1 Lowpass, Filter 1 Highpass, Filter 1 Bandpass, Filter 2 Lowpass, and Pre Filter — offer tremendous flexibility compared with the traditional one-response-at-a-time filter architecture, allowing you to mix the various filter outputs. In addition, you can independently modulate the level of each output, providing you with some serious options for patch programming.

The Alesis A6's soft knobs and buttons work with the dedicated function knobs to provide alternate methods to adjust the unit's parameters. For example, to adjust Filter 2's cutoff frequency, you can tweak the large Freq knob dedicated to that function or press the Filter 2 View button to invoke Filter 2's parameter page on the display. On that page, all of Filter 2's parameters are neatly laid out across the soft knobs, and the first knob becomes an alternate Filter 2 Frequency control.

Each voice of the Andromeda A6 has three six-stage envelope generators (EGs). The six stages are Attack, Decay 1, Decay 2, Sustain, Release 1, and Release 2. The Decay 1 and Release 1 knobs also have attendant level controls. I'm happy to report that these are looping envelopes, a feature that I've found useful since the Prophet-VS days. By default, the envelopes modulate Pitch, Filter, and Amplitude, but you can route them anywhere.

Quite a few additional controls enhance the envelopes' capabilities, including three independent, selectable Mod sources, as well as a trigger function, an initial-delay function, and a Dynamics button. Dynamics is slightly unusual in that it lets you control the behavior of the envelopes in real time in a variety of ways. For example, Normal mode is “unconditional retrigger”; the envelope retriggers with each new note played. Legato mode, however, continues the envelope from its current stage and level when a new note is played.


The Andromeda A6's digital effects section offers reverbs, delays, choruses, and a four-note pitch shifter. As many as three simultaneous digital effects are combined into an effects configuration. An authentic analog distortion processor operates independently of the digital effects. You can route the distortion's output directly to the digital effects or vice versa. Any modulation source can control effects levels.

Like most synthesizers' onboard effects, the Alesis Andromeda A6's effects are serviceable but not spectacular. Although there's a bit of routing flexibility, effects are applied only to the main stereo outputs. You can assign just one effects configuration per Program or Mix, but each Program in a Mix has its own send level. Nothing impressed me, but the A6 has good utilitarian effects that can be helpful either as an integral part of a Program or Mix or as an extra bit of subtle treatment, depending on your programming style.


When I heard about the Andromeda, processing external signals through its filters was one of the first features I was curious about. On the rear panel is an input that routes a mono audio signal to all 16 voices, allowing the filters to polyphonically process it. An additional pair of audio inputs routes one stereo or two mono signals to voices 15 and 16. Those signals replace the oscillators in the signal path so that playing the keyboard triggers the envelopes, tracks the filters, and so on to process the external audio. The input pair also employs Schmitt triggers as a modulation source to trigger any appropriate destination, including EGs.

As a straight external-signal filtering processor, the Alesis Andromeda A6 offers quite a bit of flexibility because of the power of its Pre- and Post-Filter Mix sections. The same variety of textures that are possible when using the instrument's oscillators as the filter input become even more interesting when you run external sources through the filters. For example, you can use the Mix routing mode to combine Filter 1 bandpass and Filter 2 lowpass to emphasize different, opposite parts of an input source's frequency spectrum, leaving a hole in the midrange — an unusual and (with some LFO modulation) dramatic effect.

I especially like using the Filter Feedback control coupled with the Noise/External level knob to create some extreme distortion of the Alesis Andromeda A6 filters. Predictably, that technique works especially well on drums and rhythm loops, though its usefulness isn't limited to those sounds.


The sound of the Andromeda was, according to Alesis, modeled on the original Moog modular synths. To my ears, the A6 emphasizes the high and low frequency ranges with a bit of a dip in the lower midrange. However, a lot of an instrument's perceived warmth resides in the frequencies between 200 and 400 Hz, so the A6 sounds a bit harsh or aggressive at times.

Working with the Alesis Andromeda A6, I could realize almost any analog-type sound I had in mind without too much difficulty. I was particularly interested in creating basses, percussion, and shifting drone textures, all of which the Andromeda produced quite well.

In the bass department, the A6's inherently strong low end coupled with its powerful filters made coaxing huge but defined basses from the synth simple. The filters easily handled the classic analog “resonance-snap” percussion sounds, and the combination of the LFOs and looping envelopes made complex sustained tones interesting.


The Andromeda A6 is an extremely powerful and versatile instrument that can produce an enormous range of textures. The only way to fully comprehend its breadth is to spend some time programming it yourself. The A6 is capable of real sonic depth and is reasonably simple to use, given its complexity.

Although the A6 is a well-thought-out and nicely constructed instrument that will definitely make a killer performance machine and studio piece, the factory presets don't completely do it justice. Fortunately, the programming process is easily learned by anyone with some experience with analog synths. A segment of the populace will buy the A6 just because all the knobs look cool, but if you're really interested in creating original, genuinely analog sounds, the Andromeda is one of the only modern options available.

The Alesis Andromeda A6 sounds a bit chilly, and it's not the most organic-sounding instrument. During the review process, I compared it with a Memorymoog, a Prophet-5, and a Voyetra Eight, and the Andromeda A6 definitely lacked the warmth of those older machines. Certainly, the Andromeda isn't wanting for clarity or punch, and it does have impressive bottom- and top-end “poke.” With a little work, however, it is possible to coax a warmer class of sounds from the A6, if that's what you're after.

Perhaps my biggest surprise was how uncompromising and serious the Andromeda A6 is, particularly in light of Alesis's previous synthesizers. Since the Andromeda's introduction, however, the company has gone bankrupt and been bought by new ownership, and it's attempting a phoenixlike resurrection. Alesis's tribulations aside, the A6 is definitely worth the attention of anyone serious about analog synthesis. It's certainly a lot of fun to program and play.

Peter Freemanis a bassist, composer, and producer in New York. He has worked with artists such as Seal, John Cale and Chris Spedding, Jon Hassell, Nile Rodgers, Sussan Deyhim, and Shawn Colvin.

Andromeda A6 Specifications Sound Engineanalog subtractive synthesisKeyboard61-note semiweighted; Velocity sensitive; Channel AftertouchPolyphony16-note, 16-channel multitimbralOscillators(2) analog oscillators, (1) suboscillator per voiceFilters(1) 2-pole resonant multimode, (1) 4-pole resonant multimode per voiceSequencer(3) parameters × (16) steps; (1) sequencer per ProgramROM/RAM Programs128/256ROM/RAM Mixes128/128Memory Card Slot(1) PC Card SRAM (256 KB-2 MB)Audio Outputs(2) ¼" TS main; (8) ¼" TRS individual; (2) ¼" TS aux; (1) ¼" stereo headphoneAudio Inputs(3) filter inputsControl Inputs(1) CV pedal; (1) assignable footswitch; (1) sustain; (2) CV inputsMIDI PortsIn; Out; ThruDisplay240 × 64-pixel backlit LCDDimensions40.1" (W) × 4.8" (H) × 16.1" (D)Weight47 lb.


Andromeda A6
polyphonic analog synthesizer



PROS: Flexible. Lots of dedicated controls. Fun to program.

CONS: Understandably expensive. Presets lack warmth. Heavy.


Alesis Studio Electronics
tel. (310) 301-9563