Messenger's Audio Path in Detail

So let's get straight to it. If you're familiar with the typical Moog analog monosynth—a la Subsequent 25/37, Grandmother, etc.—then Messenger's general signal flow shouldn't be much of a surprise. It's got two oscillators, a suboscillator, and a noise source, all of which get combined in a mixer; the signal from the mixer then passes to a filter, and onward to a VCA. The filter and VCA have dedicated ADSR envelope generators, and two general-purpose LFOs can be used to modulate several aspects of the primary signal path. While that might sound simple enough, with Messenger, the fun is in the details: each of these sections has some serious tricks up its sleeves, making Messenger a truly unique offering among all Moog synthesizers from both the past and present.

Let's start by looking more closely at the oscillator section. Messenger features two audio oscillators, which share a common Tune control. Each oscillator has an independent octave switch (from 4' to 32'), and oscillator 2 offers a dedicated Frequency control knob for dialing in oscillator detuning effects. This knob conveniently transposes between -7 to +7 semitones, making it quick and easy to dial in stacked fifths or any other interval you'd like between the two oscillators. The oscillator section also offers a variety of internal modulation options—including options for Hard Sync, FM, and various modulation options from the filter envelope to specific oscillator parameters. Just choose the modulation type you'd like with the dedicated switch, and use the Mod Amount attenuverter to dial in the modulation intensity to taste.

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The most notable feature of the oscillator section, though, is its unique implementation of continuously variable waveshape control. The idea of continuously variable waveshape alone isn't new, of course—it was part of the Moog Voyager and many Moog monosynths that have followed. But Messenger brings another dimension to this parameter by including a continuously variable wavefolder, accessible in the farthest counterclockwise reaches of each oscillator's Waveshape knob. In this zone, the triangle wave gradually morphs into an increasingly distorted wavefolded tone—bringing a touch of Buchla-esque, contemporary modular synthesizer tones to Messenger's palette. Each oscillator offers this possibility, which combined with FM or Sync can lead to some unruly, edgy sound design opportunities. Of course, you'll get all the other classic waveforms you know and love from other synths, too—triangles, saws, squares, and continuously variable pulse waves. Notably, the Waveshape parameters can also be modulated via the internal LFOs, envelopes, and more...excellent for all sorts of evolving tones and lively drones.

Notably, the suboscillator also offers a continuously variable, modulate-able waveshape parameter as well; however, it doesn't include the wavefolder trick. Still, you can get to triangle, square, and PWM tones with ease.

Messenger's mixer is a relatively straightforward affair, offering level control knobs for each of the two primary oscillators, the suboscillator, and the internal noise source. Messenger's mixer is relatively clean compared to some other Moog synths; each input is at unity gain at maximum. So, you won't get CP-3-style distortion tricks here—but don't fret, as the filter is gnarly enough as it is.

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Messenger's filter, as you might hope, is excellent. It's a resonant multi-mode design, complete with switchable bass compensation (Res Bass) in all modes. You get four-pole low pass (24dB per octave), two-pole lowpass (12dB per octave), band pass, and high pass responses—each as colorful, pleasant, and useful as the last. At lower resonance settings, the filter is remarkably smooth, and the resonance control itself is scaled in such a way that it's easy to dial in a ton of sweet spots without things getting unexpectedly out of hand. The filter will happily self-oscillate at high resonance settings, and can track the keyboard (albeit not quite perfectly in tune over multiple octaves on the unit that I personally tried). At lower resonance settings, the filter can serve to smoothly accentuate specific overtones of incoming tones; and when self-oscillating, it can act as a beautiful sine signal source all its own. The FB/Ext In control control either the external signal input's level going into the filter, or, with nothing connected, controls the amount of feedback introduced to the filter: acting as a gnarly distortion control. And of course, you get a dedicated attenuverter for dialing in the amount of modulation applied from the filter envelope to the filter's cutoff parameter.

There's also a dedicated Osc 2>Filter Cutoff modulation depth control, allowing for audio-rate modulation of the filter's cutoff frequency. Notably, this control can also be used to dial in wild FM tones when the filter is self-oscillating. The direct inter-oscillator FM is plenty deep and intense as it is, but if you ever really want to push into intense FM territory, I'd recommend looking toward the filter as a sound source.

After the filter, Messenger's signals pass through to an end-of-chain VCA for further articulation. However, the VCA itself has no variable parameters...so let's move on to talk about the envelopes (and modulation at large), shall we?

Modulation + Sonic Animation in Messenger

Both the filter and VCA have dedicated ADSR envelopes. These share a legato/multi-trig control, great for ensuring articulations come through clearly during rapid passages if you want them to. Notable, each of the envelopes has a dedicated Velocity response switch, allowing key velocity to scale the envelope's impact on its destination. Additionally, each envelope has a dedicated Loop switch—turning the envelopes into LFO-like sources of continuously evolving voltages. This can lead to wild re-articulated bursts of sound, complex modulated textures, and much more...taking Messenger away from its role as a straightforward monosynth and toward uses as a complex sound design machine.

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As stated before, Messenger also includes two LFOs. Each has a slightly different feature set. LFO 1, whose controls are located in the top left portion of the panel, offers selectable waveshape—with options for triangle, saw, ramp, and square shapes. You have dedicated destination selection, allowing for direct modulation of the filter cutoff, Osc 2 frequency, Osc 1 waveshape, or the suboscillator waveshape. The depth attenuverter allows you to dial in the intensity of your modulation. The Sync control syncs the LFO to divisions of the Messenger's current Tempo, and the KB Reset switch allows you to sync/reset the LFO to new notes from the keyboard, sequencer, or arpeggiator.

LFO 2, tied to the modulation wheel, allows for smooth sinusoidal/triangular modulation of the instrument's pitch, cutoff, or amplitude—or even all three simultaneously. The modulation depth is managed by the modulation wheel itself for performative modulation effects. The Pitch wheel, naturally, is hardwired to the instrument's pitch, and the Glide control introduces portamento between consecutive notes.

At first glance, that might seem to be the extent of Messenger's internal modulation tricks...but happily, that coudn't be further from the truth. Beneath the hood, Messenger has a much more complex modulation system available: one that allows you to map its many modulation sources to nearly any destination. In fact, there are modulation sources available that you might not even notice at a glance—so, what's this all about, and how can you make use of it?

The key lies in Messenger's several modulation Assign buttons—which you'll find within the LFO1 and Envelopes sections of the panel. If you press and hold the corresponding buttons and then turn any panel knob, you can use the chosen source to modulate the chosen destination. The 16 sequencer LEDs will illuminate to show you your current modulation depth (positive or negative). That's right—you can use the envelopes and LFO1 to modulate any panel knob control...so, despite the fact it might not be immediately apparent, you can modulate, for instance, the oscillator Mod Amount, the OSC2>Cutoff control, the filter resonance, the envelope stage controls, and more. And that's not all: you can use the same trick by pressing and holding several buttons in the sequencer control section. The Expression modulation source corresponds to the rear-panel expression pedal input; aftertouch and velocity correspond to the sensed strike velocity and key pressure from the keyboard. And—my personal favorite—KB S+H is a one-shot random source that updates with every key press/every note from the arpeggiator/sequencer...allowing you to randomize any aspect of your patch on a per-note basis. This modulation power is uncommon to see in a self-contained, non-modular instrument—and for me, it's the most unique and exciting aspect of Messenger's design altogether.

Of course, Messenger also features an arpeggiator and sequencer, each of which offers many options for performative control. The sequencer offers note and gate probability, as well as a selectable note pool—perfect tools for breaking away from repetitive sequences and into simple generative, evolving structures. Interestingly, the sequencer also provides the opportunity for Elektron parameter lock-esque parameter recording, allowing you to apply sequenced changes to any single variable panel control for each step of the sequence. While each step can only impact a single parameter, there's no reason that the parameter in question needs to be the same for each step—so, for instance, you could use step 5 to increase the filter resonance, step 11 to alter an oscillator's waveshape, step 12 to change the oscillator mod amount, and so on.

Naturally, Messenger has all the other niceties you'd expect from a mass-market keyboard synth: MIDI I/O, an extensive CC implementation, full patch memory with many banks, (16 banks of 16 patches, to be exact) and so on. We've only briefly touched on Messenger's many musical possibilities — and for today, we'll leave it at that. I will say this: I'm usually not terribly excited by new keyboard synthesizers, let alone monosynths; they usually feel like a repackaging of the same old ideas that have been circulating for over fifty years. But Messenger is an interesting proposition. It covers all the bases that an analog monosynth should—but it also opens up several unusual possibilities that, I suspect, will eventually define its characteristic "sound." Spoiler alert: that "sound" is something much more peculiar and unruly that you might expect from a Moog.