Moog Music Messenger: Analog FM Synthesis Unpacked

The demo begins with the classic move: patching LFO2 to modulate the pitch of oscillator 2, yielding a familiar vibrato effect. But as the LFO rate increases, the result morphs from a simple wobble into a more complex, textural modulation—showcasing how Messenger blurs the line between LFO and audio-rate FM.

Switching gears, the video demonstrates using oscillator 1 as an audio-rate modulator for oscillator 2 via the 1-2 FM routing in the mod bus. This opens the door to a much broader FM palette, with the mod amount control acting as the gateway to everything from subtle shimmer to metallic clang.

Moog’s approach here is refreshingly direct: the user is encouraged to experiment with modulation sources and depths, making Messenger a tool for both traditional FM sounds and more experimental textures.

A key takeaway from the video is the role of oscillator wave shapes in defining FM character. Messenger’s oscillators offer a range of waveforms, but the triangle wave is singled out for its ability to produce smoother, more controlled FM results compared to the harmonic-laden sawtooth.

Interestingly, while oscillator 2’s wave shape can be freely chosen for the carrier, Messenger always uses oscillator 1’s triangle wave for FM duties—regardless of its selected output shape. This design choice ensures a consistent FM response and keeps the timbral palette both wide and manageable.

The filter envelope is pressed into service as a dynamic modulator for FM depth, allowing users to sculpt evolving timbres and classic plucky FM attacks. Assigning the envelope to the mod amount is straightforward: hold the filter envelope assignment button, select the destination, and set the modulation depth with a twist of the knob.

With the filter envelope mapped to FM amount, the Messenger can deliver those archetypal percussive FM sounds, especially when tweaking envelope parameters for snappy attacks. Shifting oscillator octaves and adding the sub oscillator further expands the sonic range, making it easy to dial in everything from deep basses to shimmering leads.

The video also explores Messenger’s multitrig functionality, which ensures the filter envelope retriggers with every note—even in legato passages—unlocking consistent FM articulation. Velocity sensitivity is the final flourish, letting players inject dynamic expression into their FM patches, while manual tweaks of the mod amount control reveal yet more unexpected textures.