Inspired by the early 80s Synton Syrinx, the SER-2020 is a semi-modular monster, featuring an excellent formant filter section, unique Touch 'N Bend Control and MPE-compatible MIDI interface.

Supplier's Notes:
The SER-2020 is a monophonic semi-modular analog synthesizer with an formant filter section, designed to use as standalone synthesizer or in combination with Eurorack modules. Inspired by the Synton Syrinx *(1) added the flexibility of an MS-20. Its filter design features a combination of a 24dB / octave VC Low Pass Filter, and two independent Resonant VC Peak Filters for precise and dynamic sound shaping. The sound is ranging from solid bass sounds to articulated formant effects. Other features on the SER-2020 are the Touch 'N Bend Control together with the MPE (MIDI Polyphonic Expression) capabilities makes the SER-2020 a special instrument which response to its player. The flexible routing makes the SER-2020 a versatile machine for sound effects.

Key Specifications:
2 VCO's (CEM3340 based)
1 Sub-Oscillator
Ring Modulator
Noise Generator
Audio Mixer
Multi-Mode Sync & Sync D-Tune
3 VCF's (CEM3350 based)
2 ADSR's
2 LFO's with Reset & Shaper Modes
Auto-Glide
Multiple Triggering
Touch 'N Bend Pad
Bend Assign
Sample and Hold
Semi Modular Setup - CV inputs and outputs
Signal and Headphone output.
MIDI interface
USB MIDI interface
MPE compatible - Sensitive for; Strike (note-on velocity), Press (aftertouch), Glide (pitch bend), Slide (brightness) and Lift (note-of velocity).

The SER-2020 consist of two VCO's and one sub-oscillator, driven by VCO 1. Both VCO's deliver a triangle, sawtooth, square wave and pulse signal, which can be selected. A rich spectrum can be obtained with Pulse Width Modulation of VCO 1 and VCO 2. The LFO 1 and 2 signals can be feed to the pulse width modulation section introducing phase shift effects and Doppler frequency shifts. Since the both VCO's have a separate LFO for PWM, chorus-like effects can be obtained by controlling both pulses with different LFO speeds. VCO 2 can be synchronized to VCO 1 in different modes. Synchronization is applied when two or more VCO's have to produce exactly the same pitches, without phase shift or beat effects. When VCO 2 is detuned from VCO 1 another effect occurs, which will result in quite dramatic tone colors.
Each VCO has an individual output, also the noise generator and sub-oscillator has individual outputs.

The most important sections of this synthesizer is the filter. The SER-2020 features a very extensive filtering system, which consists of the standard 24 dB / octave low pass filter and two independent band pass filters, which together form the Voltage Controlled Formant filter.
Both band pass filters have a frequency control and a resonance control for setting the selective amplification in the pass band. The bandpass filters are equipped with a control voltage mixer for LFO, ADSR and key range voltages. The LFO control can be used for the external modulation input.
The low pass filter is an standard 24 dB / octave roll-off. It has a frequency control and a modulated CV mixer from several sources like LFO, ADSR and the key range. The LFO control can be used for the external modulation input. Also the resonance of the low pass filter can be controlled.

The SER-2020 has two ADSR generators, of which one is used to control the internal VCA, and the other one to control the filter section. The control signal can be inverted by means of the ADSR controls in the filter section, so that the filters can be swept in opposite directions.
ADSR 1 and 2 have a positive and negative (inverted) direct output available on the patch panel.

The SER-2020 has two independent Low Frequency Oscillators (LFO's) of which the rate can be controlled, and for LFO 2 also the wave shape.

LFO 1 generates a triangle wave which exclusively is routed to the pulse width modulation control input of VCO2. LFO 1 also generates a square wave and a pulse wave. The square wave is available as direct output on the patch panel. The pulse wave of LFO 1 is internally routed to the sample and hold generator as clock source.

LFO 2 is more versatile and can be used for the modulation of the VCO's and the filters. Moreover LFO 2 can be used as a one shot generator which means that a signal is generated much alike an Attack / Release generated function. Except for the LFO 2 rate control with the preset knob, it also can be controlled dynamically with the pad.

Several sections in the synthesizer can be controlled with the bend pad, by pressing it with the left hand index and middle finger. The pressure sensitivity for the VCO, VCF and VCA can be adjusted. The touch 'N bend pad also reacts on the MIDI modulation control and the MIDI brightness (CC#74) control for MPE compatibility.
Also the speed of the rise / decay mode of the LFO 2 is possible. Pressing the UP pad will result in a shorter cycle, and pressing the DN pad in a longer cycle.