KEYBOARD a 44 keys compact keyboard (no velocity) with wooden end panels, 41 pots for tweaking sounds, 6 buttons and 13 small switches. On the left controls for overall portamento and detune, and a switch for transposition (an octave up or down).
->In 2020 Behringe made clone of the mp4, the behringer monopoly
KEY ASSIGN a special feature of the mp4 is the voice assign, a bit different from classic monophonic:
- Unison stacks all 4 VCOs
- Unison / Share assign all voices available
- Poly four voice in polyphonic paraphony, which means mp4 share one common VCA and VCF envelope
- Chord mode, like old Poly-800, allows to record a chord and play with a single note
1-Clock input for arpeggiator (pulses)
2-pedalswitch input for portamento mode
3-VCF cutoff CV input
4-VCO FM CV input
5- gate input switch between +15V and s-trig modes
6-Trigger (gate) input
7-Trigger (gate) out
8-Control voltage pitch input of course MONO (1V/Oct not usual Korg Hz/V)
9-Control voltage pitch output (1V/Oct not usual Korg Hz/V)
11- main mono output
SOUND subtractive all analog with four VCOs based on SSM 2033 with 3 shapes: triangle, sawtooth and square wave with variable and modulable pulse width + 1 white noise generator circuit. VCO octave range is 16 ', 8', 4 'and 2' , and each oscillator has indivifual volume control and tune pot (about 50 cents).
OSC SYNC One of the most interesting (and unique) features of the Mono/Poly is the sync ("Syncro") and cross-modulation ( "X-Modulation") options between the 4 oscillators. In Syncro and X-mod Single mode, the VCO1 is the master syncing the other 3 VCOs to it . In Double mode, both VCO1 VCO2 are masters, syncing VCO3 to VCO1 and VCO4 to VCO2.
FILTER Punchy 4 slopes resonat Low pass filter based on classic SSM 2044, with key tracking option (150% doesn't work with external CV control)
ENVELOPE: 2 EGs for VCA and VCF type 4 segments ADSR. Different retrig mode for EG (Single and multimode)
LFO main modulator MG1 is assigned to MOD wheel with triangle and sawtooth shapes, 0, 1-20 Hz frequency range, and can modulate VCO pitch, filter VCF and pulse width. A second modulator MG2 (only triangle shape) is simpler.
ARPEGGIATOR: Range: 1 oct, 2 oct or full with UP or DOWN or UP / DOWN direction and LATCH mode