Diodorus

Diodorus synth specifications:
This synth plugin which reproduces the sound of late 1990s hardware virtual analog synths. It aims to be the ideal synth of 1997 in software, and brings back to the foreground the feature of morphing between two different sounds with easy control:

• Polyphony: 24 voices (split 12 + 12 across the two timbral slots in Layer/Split).
• Engine: bi-timbral — Single, Layer, Split, and Scene Morph modes.
• Format: VST3 (Windows), 64-bit. Stereo out.
• Presets: Over 500 factory across 20 categories, plus 40 user preset slots.

Oscillators (×3, per voice):

• 5 waveforms per oscillator: Saw, Sine, Square, Triangle, Ensemble. Ensemble is a 7-saw detuned stack per oscillator (centre + 6 sides, up to 55 cents spread) with its own Detune and Mix controls with a full multi-saw inside each oscillator slot.
• Tuning per oscillator: Octave ±2, Coarse ±24 semitones, Fine detune ±50 cents.
• Pulse width 5–95%.
• Oscillator FM / cross-modulation: each oscillator can be phase-modulated by any oscillator including itself (feedback FM), modulation index up to ~8 radians. Any routing such as self-feedback, A B A loops is stable.
• Hard sync (osc 2 to osc 1) with band-limited sync transitions.
• Noise generator with its own level.
• Detune per-oscillator.

Filters (×2, per voice):

• State-variable design, Lowpass / Highpass / Bandpass independent per filter.
• Selectable slope per filter: −12, −18, −24 dB/oct.
• Routing: Serial, Parallel, or Split (osc 1 filter 1, osc 2+3 filter 2).
• Cutoff 20 Hz – 20 kHz (logarithmic), resonant.
• Bipolar filter envelope amount (±) and keyboard tracking, independent per filter.

Envelopes:

• Amplitude ADSR, logarithmic time scaling.
• Filter ADSR, shared by both filters with independent amounts.

Modulation:

• 3 LFOs per voice (free-running, per-voice phase) with various waveshapes including Sine, Triangle, Square, Saw Up, and more.
• Rate 0.1 – 20 Hz (logarithmic). Direct destinations: Pitch, Filter 1 Cutoff, Filter 2 Cutoff, Amp, Pulse Width.
• 8-slot modulation matrix, per slot: Sources: LFO 1/2/3, Mod Wheel, Destinations: Pitch, Filter 1 Cutoff, Filter 2 Cutoff, Amp, Pulse Width. Bipolar amount, response curve (Linear / Exponential / Logarithmic / S-curve), and slew (0 – 2 s) per slot.

Voicing:

• Poly and Mono modes, legato on/off.
• Portamento/glide 0 – 2 s.
• Unison 1–4 voices per note with detune (to 100 cents) and stereo spread.

Effects

Full independent chain per timbral slot:

• Distortion with Soft/Hard clipping, drive, tone, wet/dry mix.
• Ring Modulator featuring carrier 10 Hz – 2 kHz, mix.
• Chorus / Flanger — dual mode, rate 0.05 – 10 Hz, depth, feedback, mix.
• Stereo Delay with 20 ms – 1.5 s, feedback, mix, smoothed time changes.
• Reverb featuring comb/allpass network with room size, damping, stereo width, mix.

Arpeggiator:

• Modes: Up, Down, Up/Down, Random.
• Rates: 1/4, 1/8, 1/16, 1/32, synced to host tempo.
• Range 1–4 octaves, gate length, swing, latch, and note order (Pitch / As Played / Reverse Played).
• Latch releases automatically when the host transport stops.

Bi-timbral engine:

• Single sound mode or Layer with two different sounds stacked, each with its own oscillators, filters, envelopes, mod matrix, arpeggiator and full FX chain.
• Split, with user-selectable split point on keyboard.
• Scene Morph feature offers a single continuous control interpolates the whole patch between two scenes. Continuous parameters glide; discrete ones (waveforms, routings, on/off switches) snap at the midpoint, so a morph never produces a broken intermediate state.
• Per-slot Level, Pan (equal-power), and Transpose ±24 semitones; user-set split point.

Presets:

• Over 500 factory presets in categories including Pad, Lead, Sequence, Strings, Choir, Bass, Brass, Polysynth, Chime, Pluck, Stab, Electric Piano, Clav, Marimba, Saw Stack, Gated and more.
• 40 user preset slots — save and recall your own patches.
• 80-slot Expansion section with bank import/export (.vabank), so expansion preset banks can be loaded.

v1.0.0 update:
v1.0.0 features bug fixes to solve problems in portamento and mod wheel modulation. It also adds three new mod-matrix destinations — LFO 1 Depth, LFO 2 Depth, LFO 3 Depth.
Lead and pluck presets now respond to the mod wheel with vibrato and filter movement.
Also now in v1.0.0 selecting a single preset after a Layer or Split no longer leaves the second slot sound from previous layered preset sounding with a newly-selected single preset.