ES20 Analog Synthesizer

A classic semi-modular, cables and all.

The ES20 is a patchable synthesizer inspired by a late-seventies semi-modular classic. Expect thick basses, cutting leads and the unmistakable character of two resonant filters in series. It works straight out of the box, with normalled connections ready to play. Add patch cables to reroute its signal path and modulation, and take it in new directions.

Two filters, two characters

The high-pass and low-pass filters can be driven into pronounced resonance, right up to self-oscillation. Choose the Early model for a more aggressive response or Late for a smoother, rounder character. Run them in series to shape everything from tight, focused basses to sharp, resonant sweeps.

A patch bay built for experimentation

Every jack has a normalled connection, so the ES20 works without a single patch cable. Repatch the envelopes, noise, sample & hold, modulation wheel and other sources to change how the synth behaves. Reroute modulation, create feedback paths and push familiar sounds into unexpected territory. Your cable connections are saved with each patch.

Turn audio into control signals

The External Signal Processor extracts pitch, envelope and trigger information from incoming audio. Feed it vocals, guitars, drum loops or another synthesizer, then use the resulting control signals to play the ES20, trigger events or modulate its parameters. Track a bass line, follow a melody or let a drum hit drive the filter.

Sequencing and effects, built in

The SE-10 provides a three-channel, twelve-step sequencer for bass lines, repeating phrases and evolving patterns. Chain steps for longer sequences, or use free, synced or external clocking to fit it into your setup.
The FX-30 adds drive, modulation, echo, tremolo, reverb and compression. Both units fold out when you need them and stay out of the way away when you don’t.

From mono to twenty voices

Use the ES20 as a monophonic instrument, switch to polyphonic operation with up to 20 voices, or select five-voice unison for a thicker, detuned sound. Adjustable drift and hum bring additional variation inspired by the behaviour of analogue hardware.

460 factory patches

Explore 460 patches covering basses, leads, keys, pads, textures, percussion, sequences, external processing and sound effects. Use them as ready-to-play sounds or starting points for your own patches.

Requires Reason 14 or later!

Specifications

Voice modes: Mono, polyphonic (2–20 voices) and five-voice unison, with detuning.

VCO 1: Triangle, sawtooth, pulse and white noise; 32′, 16′, 8′ and 4′ ranges.

VCO 2: Sawtooth, square, narrow pulse and ring modulation; 16′, 8′, 4′ and 2′ ranges; ±1 octave pitch adjustment.

Filters: High-pass and low-pass VCFs, 50 Hz–15 kHz, with self-oscillation and Early/Late circuit models.

Envelopes: EG 1 with delay, attack and release; EG 2 with hold, attack, decay, sustain and release.

Modulation generator: 0.1–20 Hz, waveform morphing and tempo sync from 1/1 to 1/32.

Patch bay: Normalled connections with patch cables; sample & hold, second VCA, pink and white noise, wheels and pedal as CV sources.

External Signal Processor: Pitch-to-CV, envelope follower and trigger generation.

SE-10 sequencer: 12 steps × 3 channels, up to 24 chained steps, free/sync/external clock and TRIG 1–12 outputs.

FX-30 effects: Drive, modulation, echo, tremolo, reverb and compression.

Performance controls: Portamento, pitch-bend range up to 24 semitones, velocity amount, note priority, legato and retrigger.

Back panel connections: CV inputs for pulse widths, levels, both filter cutoffs, MG rate and volume; CV outputs for keyboard, envelopes and MG; MERGE and MULT.

Factory library: 460 patches across nine categories; Bass, Leads, Keys, Pads, Textures, Percussion, Sequenced, External Processing and SFX.