Like most oscillators also the Mangrove has a coarse frequency control, a fine tune potentiometer with one octave span and a 1V/octave pitch input (abbreviated here with V/8).
Linear frequency modulation is found as well and the FM INDEX socket is a VCA controlling the modulation depth, unfortunately an often omitted feature. When nothing's patched to this socket we always have full modulation intensity.
Output-wise there's a square output reacting to pitch and FM only and has to be considered a secondary output only for synchronisation tasks or for FM'ing. The main output called Formant reacts in addition to all sound shaping parameters of the Mangrove which we will describe now:
The parameters Formant and Barrel interact with each other. The first one sets the sound character by moving resonance peaks (alias formants) in the frequency spectrum; compare it to different pitches of human voice from tenor over alto to soprane. Barrel however determines harmonic density by waveform selection, fading from sawtooth over triangle to ramp.
In it's fully counterclockwise position the Barrel potentiometer will generate untertones (utone). Now a frequency division occurs and you can use the Formant control, that changed it's function, to move thru the undertone scale (from one octave below over octave & 5th over two octaves below etc.).
AIR is a post-formant-output VCA with overdrive. It's CV input has a bipolar attenuator and the VCA is very fast so you can modulate it with audio.
Unique and one of the most interesting issues about the Mangroves VCO is the switch that selects between two radically different modes: constant wave and constant formant.
Constant Wave complies to the usual approach: Pitch alters frequency and all other controls change the waveform.
Constant Formant divides the tone-creating impulse from the pitch; the harmonic spectrum is being locked. The formant parameter now determines the pitch range or "instrument's size" and the Barrel the timbre. It is hard to describe in words - watch the video to hear the difference.
Pitch input, Sync input
FM input, FM Index CV input
parameter CV inputs: Air, Barrel, Formant
outputs: Square, Formant
3U Eurorack module, 10HP wide, 30mm deep
power consumption: 58mA @ +12V and 54mA @ -12V