A few months before I took on the review of the Alesis Andromeda analog synth, my nine-year old son Josh got me back into the sound of the old analog synths by listening to some of my classic records that used analog keyboards.
Product Points
Applications: Studio, live sound

Key Features: 16 voices; 32 VCOs; 32 VCFs; sequencer; MIDI control; ribbon controller; 61-key semi-weighted keyboard; patch memories; temperature monitoring; memory card slot; LCD display

Price: $3,499

Contact: Alesis at 401-658-5760, Web Site.

The first song we listened to was the early 1980s hit, "While You See a Chance" by Steve Winwood. I explained to him that the amazing keyboard solo was performed on a Moog synthesizer (though, that meant little to him). Then we listened to Herbie Hancock's "Rockit" (more Moog). And Yes, with Rick Wakeman, on "Close to the Edge" (even more Moog).

After years of composing and creating music on such hybrid "virtual analog" synths such as the Korg DW-8000, XP-80 from Roland, and various pieces of FM technology such as the DX-7, DX-11 and TX-81Z from Yamaha, I was ready to plug-in to what was going to become my first experience with a pure analog piece of equipment.

Features

The A6, priced at $3,499, is truly one of the most beautiful sounding instruments I've had the pleasure to use for music creation.

At its core, the A6 provides 16 individual voices, emanating from the onboard circuitry, to generate raw audio. It uses 32 VCOs (Voltage Controlled Oscillators) for the rudimentary sound sources (two per voice) with hard/soft sync and sub-oscillation; four periodic waveforms consisting of: saw, sine, pulse and sawtooth; and two aperiodic waveforms consisting of: Random and Noise. There are 32 true analog VCFs (Voltage Controlled Filters) with resonance (two per voice).

The A6 also provides CV (control voltage) inputs that allow you to plug-in external devices or instruments via the 1/4-inch jacks and route them to the oscillators and filters. These sources can consist of other keyboards and synthesizers, as well as other pieces of instrumentation.

The A6 contains a very comprehensive effects model, robust MIDI capabilities, a 16-step sequencer, ribbon controller and a very, very useful 260 x 64 backlit multifunctional display. According to Alesis, the Andromeda was crafted after the original modular Moog synths.

Given that we're talking true analog circuitry, the A6 is affected by temperature changes that take place during storage and shipment. The manual recommends that one of the first things you do with the 50-pound keyboard is tune it. And, unlike VA or hybrid synths, all 16 of its voices, and oscillators and filters within each voice, need be tuned. Once done, the A6 monitors ongoing temperature changes by providing "Background Tuning" in the analog hardware and modifies the settings based on its internal controls (temperature tuning).

The A6 is configured in five octaves (61 semiweighted keys; C-to-C). I found the keyboard to be much more responsive than most synths and very comfortable to play.

The A6 operates in either Program mode, or Mix mode. In Program mode, you play a single sound across the entire keyboard versus Mix mode where you're able to play various sounds in different ranges across the keyboard, or split and layer voices across the entire 61 keys. In total, you have 512 patches in which to work with (256 preset and 128 user-defined programs, and 128 additional Mixes).

The A6 provides a very intuitive way of approaching subtractive synthesis design and provides a physical layout (72 knobs, 144 buttons and countless green LEDs that look pretty cool in a dimly lit studio) that lets you physically route the audio signal from left to right - almost as if each of the function groups across the top of the keyboard were a module that could be patched to something else. This signal path is eventually sent out the master mix section on the right side of the instrument.

You cannot use this instrument without praising the 240 x 640 backlit screen, and for someone new to analog synthesis programming, I can't imagine anything more useful on this instrument.

There is a tremendous amount of flexibility with the controllers which include two mod wheels (commonly set up as the pitch wheel and modulation wheel) after-touch control, sustain, foot switches, CC pedal, and a very cool ribbon strip that's actually split in the middle for dual assignment.

The A6 lets you enable or disable the MIDI controllers from the mix channel providing you with the ability to isolate any one of the programs in the mix so you can hear it without having the other programs layered on top of it. I found this to be very helpful especially when it came to mixes that were created from complex layers.

The A6 provides several different ways of storing edited programs or mixes to memory. There is also an onboard Directory listing of all programs and mixes in memory so you can see the content of each preset bank. You do have the option of saving new edited presets to a memory card (PC-Card Type 1 SRAM) that plugs into the back of the Andromeda.

Whereas some synthesizers provide standard modulation and pitch bend wheels, the A6 provides a unique level of assignability to both controllers. You are not restricted to using each only for its traditional designated purpose, but are able to also assign these wheels to modulate any parameter of sound that is designated as a modulation destination.

The ribbon controller, one of my favorite performance features, also provides another tactile way of modifying sound. It modulates the audio simply by sliding your finger across the fixed Ribbon Strip which is in a sense is like mod wheel, only it's flat, made out of fabric and is about foot long.

The A6 has a global clock function that provides tempo information for the onboard sequencer, arpeggiator and modulation sources. The sequencer, in this case, is a basic 16-step, three-level modulation source/note triggering module. It is utilized on a per program basis, meaning each one of the 128 internal programs can have its own sequence stored in memory.

To achieve the lush classic sounds of older analog instruments, the Andromeda features two-pole (12 dB/octave) multimode and four-pole (24 dB/octave) low-pass derived resonance filters, which are reminiscent of classic analog processes. The A6 provides two VCFs for removing frequencies during program creation, and is of course, the essence of why this is called subtractive synthesis.

The A6 has four modes: low pass, high pass, band pass and notch, like the original SEM. Alesis took the classic oscillator-filter-envelope functionality and added additional capabilities.

The four-pole low-pass filter was designed to emulate the Moog modular synths introduced in the late '60s. The A6 provides the basic origination points for modulation that you'd find in just about any synth: LFOs, envelopes and a tracking generator used for reshaping the sound source. The Key Track knob actually sets the amount of tracking effect that the A6 has on the filters. In this part of the keyboard, the A6 provides an unprecedented structure for mixing the various outputs together.

The A6 provides several means of modulation-based configurations. Some are actually hardwired inside the synth, and some are software based - meaning that they are originated as a "digital" source, and routed through a D/A converter. They are used as analog modulations before being incorporated into the signal flow.

The envelopes are used when you want to make a change in frequency over time, or basically adjust the contour or shape of a sound. Envelopes can be routed to many destinations in the A6, and an envelope or any of its parameters can also be a destination. Each envelope in the A6 has seven stages that can be modified over time: Delay, Attack, Decay 1, Decay 2, Sustain, Release 1, and Release 2.

LFOs are not sent to any of the synth's audio sources, but are simply meant to generate waveforms and/or a noise source and act as a mod source. There are nine LFO parameters.

The A6 offers three methods to mix the A6's sound sources together. Pre-Filter, Post-Filter and Voice Mix. The pre-filter determines the blend going into the filters and post-filter mixes the filter's outputs in addition to unfiltered signals going into the VCAs controlled by Envelope 3 (Amplitude). The Pre-Filter mix combines the levels of the VCOs, and also incorporates the inputs from a noise source, feedback and ring modulator.

The Post-Filter mix has five controls that control the output of the filters being routed to the voice mix, plus the unfiltered signal levels of the oscillator's sine waves and ring modulation signal. The Voice Mix is the final mixing stage, and sends all audio to the master volume control and any changes here affect all 16 voices.

In Use

It's probably best to simply experiment in order to get a feel for the mixing system. I simply turned down all of the editable parameters and began to create a sound from scratch.

In the Modulation Matrix, any source can be routed to any destination. The matrix itself isn't available to view, but rather thought of as a reference to "source" and "target" destinations. There are four ways in which you are able to control the modulation paths: Hardware (front panel controls); Custom (manipulation of the modulation matrix); Fixed software (triggered sources); Control of Custom Mods (the ability to effect the modulation path by way of a controller).

The A6 has 45 MOD buttons placed across the front panel and when you activate one of them next to one of the soft knobs, you're actually assigning the "destination" or what's going to be modulated.

Two complete systems of effects are available: analog-generated distortions (fuzz, overdrive, etc.) and digital effects (reverbs, delay, chorus, pitch shifting, etc). The effects processors are sent the signal from the Voice Mix. The output of the effects processors has its output sent directly to the main outs only. You have control over wet and dry mixes in the effects pages.

Overall, once I had mastered the basics of this keyboard synth, and became familiar with its complex operation, the created sounds were impressive. Ultimately, I came very close to creating those classic analog synth sounds that were prevalent in the 1970s.

I had a few criticisms and suggestions including a recommendation to add a 10-key number pad to the front panel for quick data entry and maybe Alesis could provide manual tutorials throughout the manual; the first one came up in the Effects section, "How to Edit a Reverb" on page 208, nearly 2/3rd of the way through the manual.

Summary

Because of the complexity, this keyboard is certainly not for everyone, and Alesis sells several digital alternatives for synthesis creation that may satisfy your desire for analog modeling (Ion and Micron).

But if you are willing to delve into the intricacies of pure analog synthesis, the Alesis A6 Andromeda provides an unprecedented level of control to create some of the richest analog synth textures available today. From ripping leads, to warm pads, lush strings, and fat bass lines, this is one of the most impressive keyboards I've ever played.

It is the perfect studio companion to my arsenal of virtual analog and devices, and the plethora of plug-ins I use in my DAW configuration. Check it out if you dare.