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This page is read from MIDI Instrument Definitions, a Python library used in the author's other projects, in which every number is traced to a document its maker published. Its source is on GitHub.

Vermona PERfourMER MKII MIDI implementation

The MIDI implementation of the Vermona PERfourMER MKII: what it answers to, and the 1 control it offers.

At a glance

Firmware
Not recorded.
MIDI channel
Any one of 1 to 16.
Parts
Synthesizer Channel, 4 of them: each on a MIDI channel of its own, taking notes and controls, with 1 voice each.
Voices
Each part's own, under Parts.
Note range
Not recorded.
Velocity
Received.
Aftertouch
Channel pressure, one value for every key.
Pitch bend
Not recorded.
Program change
Not recorded.
MIDI clock
Received.
Start and stop
Not recorded.
Control change
1 control, in the table below.
NRPN
Not recorded.
System exclusive
Not recorded.

Controls

In the order the definition gives them, by part and group. Under each control is the name a program calls it by, once pymidiinstrumentdefs.load("vermona/perfourmer_mkii") has loaded them.

Synthesizer channel

Control CC Values
Modulation Wheel
modulation_wheel		 1 0-127
Received, never sent

Where these facts come from

Source documents

How they were read

A RETAILER'S COPY THAT IS VERMONA'S OWN FILE. Vermona's support page for the PERfourMER MKII offers two downloads, PERfourMER MKII - patchsheet and Lowpass, 12 dB/octave - manual sweep, and no manual, though it warns that its database "is not filled with all contents, yet!" (support_page); the product page lists no downloads at all (product_page). The manual cited is Kraft Music's copy, a retailer's. It is byte for byte the file Vermona's own site offered from its old product page as "PERfourMER MKII Manual (EN)" (old_product_page), p4m2_manual_en.pdf: the Wayback Machine's index gives one SHA-1 for all seven of its captures of that file, from 2011-11-11 to 2015-05-30, and it is this file's. That address answers 500 today (2026-10-10). So what is cited is Vermona's manual, labelled as a third-party copy only because Vermona no longer serves it. A second copy on the Internet Archive, from 2020, is the same bytes again; another item there that is labelled as this manual holds the Action Filter 4's.

ONE EDITION KNOWN, PRINTING NO DATE. The manual prints no edition, version or date. Its PDF was made on 2011-10-31 and changed on 2011-11-01 by its metadata, and every capture of Vermona's address, from 2011 to 2015, holds those same bytes. Every page from 2 on prints its own file page as its folio.

FOUR SYNTHESISER CHANNELS, EACH ASSIGNED A MIDI CHANNEL. "On one hand, the PerFourMer MKII is a four-voice polyphonic analogue synthesizer with a classic voice structure. On the other hand, it offers four independent synthesizer channels." (manual p. 6). Each is given a MIDI channel in the panel's MIDI mode, by choosing one of (1…16) with SELECT/SEQ and pressing the TRIG button of each synthesiser channel that is to take it (manual p. 25). So they are one part, synth_channel, of four, with channel: assigned - in every playmode but the two Duo modes, below.

EACH SYNTHESISER CHANNEL IS ONE VOICE. Each voice has one oscillator, "four VCOs in total" (manual p. 7), and a channel that shares its MIDI channel with no other plays in Mono 1: "Mono 1 is the standard-mode for all synthesizer channels not being combined." (manual p. 25), "disregarding the selected PLAYMODE setting." (manual p. 26). Vermona's product page says so outright, in the part's own name: "PERfourMER MKII consists of four full-fledged monophonic synthesizers (synth channels) that can be combined at will to create unusual or classic sounds." (product_page), as its old page did: the instrument "combines four discrete built monophonic analogue synthesizers into a single rack-mountable, desktop unit." (old_product_page). So each part is recorded with polyphony: 1, and polyphony_shared: false: a combined group deals its one MIDI channel's notes across its own channels' voices, and no page has a group take a voice from a channel outside it, so the parts are read as not drawing on one pool.

COMBINING THEM IS A SETTING, WHICH NO FIELD HOLDS. "To combine synthesizer channels, simply set them to identical MIDI-channels." (manual p. 25), and a PLAYMODE then decides how the combined channels take notes. Mono 1 plays them all in unison as "a singular monophonic synthesizer" (manual p. 25); Mono 2 deals notes out in turn, "The first MIDI-note will trigger e.g. channel 1, the next channel 2 and so on" (manual p. 26); Poly 1 plays them "with up to four-voice-polyphony" (manual p. 27), a fifth note taking the oldest voice, and Poly 2 is "almost similar to Poly-1-mode" (manual p. 27); and the two Duo modes split the four into two units, channels 1 and 2 and channels 3 and 4, in which "the synthesizer channels are constantly combined and played by the synthesizer channels 1's MIDI-channel." (manual p. 27). So in the Duo modes channels 2 to 4 answer on channel 1's MIDI channel whatever they are set to. How many notes a MIDI channel holds therefore runs from one to four, by how many synthesiser channels share it and the mode. The panel has one PLAYMODE control (manual p. 25), and no page says how it applies to two groups combined on different MIDI channels; and the manual and the product page describe Duo 1 differently, below. So voicing_modes and an instrument-wide polyphony are not recorded.

THE MANUAL AND THE PRODUCT PAGE DESCRIBE DUO 1, AND IN PART DUO 2, DIFFERENTLY. The manual: "Duo1-mode allows playing both units (voices) with monophonic alternating voice-fetching, similar to Mono-2-mode." (manual p. 27), and Duo 2 "allows the two voice units to be played duophonically." (manual p. 28). The product page: D1 - duophonic, unison and D2 - duophonic, rotating (product_page). No field depends on it.

ONE NUMBERED CONTROLLER. The square wave's pulse width "can be varied using the modulation wheel (MIDI CC #1)." (manual p. 7), switched on and off for each synthesiser channel by edit parameter 2 (manual p. 29), and the product page agrees: "PWM via LFO or MIDI (modulation wheel CC#1)" (product_page). So modulation_wheel is CC 1 on the synth_channel part, received only: the MIDI connections are an input and a thru, the thru being the one MIDI output and passing the input on (manual p. 23), and no page names a MIDI out. The cutoff "can also be modulated and controlled by MIDI aftertouch or a corresponding MIDI control command." (manual p. 12), but no page numbers that controller, so it is not carried, and control_change is left unset rather than read as a map of one. Page 12 puts that controller and MIDI aftertouch under one switch, edit parameter 3, which p. 29 describes as channel pressure alone.

WHAT ELSE IS RECEIVED. Each of these is switched for each synthesiser channel by an edit parameter (manual p. 29): note-on velocity, to the amount of the VCA's envelope (parameter 4); channel pressure, to the cutoff, as "(channel) after touch data" (manual p. 29) (parameter 3); and the pitch bender, to the oscillator (parameter 1), read as MIDI pitch bend because no page gives the instrument a bender of its own, over a range no page gives. MIDI clock is received for the LFOs - "All of the PerFourMer MKII's LFOs can be beat-synced to a MIDI-clock." (manual p. 18) - switched per synthesiser channel by edit parameter 8 and divided to one of eight note values (manual p. 18), with an internal clock as a global alternative (manual p. 19).

NOT RECORDED: firmware, which no page names; the note range; the bend range and whether it is settable, which are all that the format's pitch_bend holds, so it is left out; note-off velocity; transport, program change, system exclusive, NRPN and channel-mode messages, which no page mentions; and the MIDI channels a reset restores, since "The Reset only affects the EDIT parameters and MIDI channel settings." (manual p. 30) without saying to what.