Vermona's approach to four-voice synthesis is refreshingly unconventional—instead of a traditional polyphonic engine, the PerFourMer MKII gives you four complete monophonic synthesizers that can be patched together in six different configurations, letting you move fluidly between solo lines, two-voice duets, and full four-voice polyphony depending on what the moment calls for.
Each of the four channels runs through the same core signal path: an analog oscillator with sine, triangle, sawtooth, and square waveforms plus noise, feeding into a 24dB resonant lowpass filter with individual cutoff and resonance controls. Every channel gets its own ADSR envelope and LFO, both of which can modulate pitch, filter, or amplitude. The LFO goes into audio rates and offers sawtooth, sine, square, and sample-and-hold shapes. You can also modulate pulse width via LFO or MIDI CC, and sync oscillators between channels for classic hard-sync textures. Each voice has its own output plus individual pan control, so you can route them to different effects chains or a mixer.
The real magic happens in how the channels interact. Beyond standard polyphonic play modes, you get unison and rotating monophonic modes, duophonic configurations, and the ability to use frequency modulation between any channels. There's also a filterbank mode that lets you feed external audio into each channel's filter section, turning the whole unit into a four-band parallel processor. MIDI in and thru ports handle note data and modulation, and the CV and gate inputs give you hardware sequencer compatibility. The unit sits in a 19-inch rack format at 5U height, though it's equally at home on a desktop.
The PerFourMer MKII has earned respect in the community for its warm, organic sound and hands-on immediacy—every parameter has a dedicated knob with no menu diving required. The architecture rewards experimentation, and the combination of individual outputs with flexible routing makes it surprisingly powerful for a desktop unit. Some users note the learning curve around play modes, but once you understand how to combine the channels, the creative possibilities expand considerably.
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