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The Panel
The lower strip contains previous/next program controls, the patch name and
browser, WRITE, CONFIG, and master VOL. Master volume is not stored in
.sy1 patch data.
Banks and patches covers the browser, the formats it reads and where everything is kept. MIDI control covers what a controller does and how to change it.
Oscillator 1 — sine, sawtooth, pulse, triangle. Oscillator 2 — sawtooth, pulse, triangle, noise. No sine; oscillator 1 has no noise. The two sets differ by one entry at each end.
Important: The oscillators use different stored waveform identifiers. Oscillator 1 displays
0–3; oscillator 2 displays1–4. See Parameter storage before generating patch data.
Pitch (±60 semitones) and fine tune (±60 cents) offset oscillator 2 against oscillator 1. Note that fine tune's default is +15 cents, not zero — that is the reference plugin's init sound, and it means a patch that never touches fine tune has a permanently sharp second oscillator. Deliberate for width; wrong for an organ.
Key tracking off makes oscillator 2 play a fixed pitch regardless of the note.
Mix crossfades the two: out = osc1·(1−m) + osc2·m.
Sub oscillator — at oscillator 1's pitch or one octave below, with its own waveform. Its measured mix law compensates the oscillator-1 side as sub level increases.
Cross modulation:
- FM — oscillator 2 modulates oscillator 1. This is frequency modulation, not phase modulation: the displacement accumulates into the running phase, so the phase carries the integral of the modulator.
- Ring — the two outputs are multiplied. Produces sum and difference frequencies, which are generally inharmonic; this is where bell and metallic tones come from.
- Sync — oscillator 1 is the master. Every time it completes a cycle it resets oscillator 2's phase. Sweeping oscillator 2's pitch under sync gives the classic tearing sync lead.
FM and ring are mutually exclusive; ring takes precedence.
Five types: LP12, LP24, HP12, BP12 and LPDL, the diode ladder added in v1.13 beta 2. Cutoff, resonance, saturation, keyboard tracking, envelope amount, and its own ADSR.
Two notes on what those actually are, both settled by measurement rather than by documentation:
- State 3 is a band pass, not the 24 dB high pass the English manual describes. The two manuals disagree — the Japanese one for the same version calls it a 12 dB band pass. Driving noise through it settles it: its pass band is bounded at both ends and tracks the knob (339–761 Hz at one setting, 1356–3417 Hz at another), falling about 6 dB per octave on each side. A high pass does not fall above its corner.
- LP24 and LPDL currently use the four-pole zero-delay-feedback ladder path. LPDL does not yet use a separate diode-specific nonlinear model, so the two states share the same DSP topology.
A notch response exists in the DSP layer and is reachable through the engine, but no Synth1 filter state selects it — the reference has no notch, and inventing a mapping to reach it would corrupt every patch that uses a real state.
Keyboard tracking moves the cutoff with the note. At full tracking a patch sounds equally bright everywhere; at zero, high notes get progressively duller because the same cutoff removes proportionally more of them. Most acoustic instruments sit somewhere in between, which is why partial tracking sounds natural.
Saturation applies a peak-normalized algebraic nonlinearity to the filter output. It increases small-signal gain and harmonic density while preserving a normalized full-scale input peak.
ADSR, gain, velocity sensitivity, pan.
Attack is linear; decay and release are exponential approaches. That split is deliberate — a linear attack reaches exactly 1.0 in finite time, so "attack finished" is a state the generator can enter, while an exponential decay gives the familiar shape without needing to be told where it is going.
A third envelope, with attack and decay only, routed to one of: oscillator 2 pitch (up to 24 semitones), FM amount, or pulse width. This is what makes a pitch-swept sync lead or an FM bell whose brightness decays.
Six waveforms: sawtooth, triangle, sine, square, sample & hold, smoothed random. Each has a destination, depth, speed, optional tempo sync and key sync.
LFO waveforms are not band-limited, unlike the audio oscillators. That is intentional: an LFO wants its exact corners, and PolyBLEP overshoot on a square LFO would be an audible pitch or cutoff blip rather than an anti-alias measure.
Four patterns: up, down, up-down, random. Four octave-range settings. Gate length. Nineteen rhythmic divisions from a whole note down to 1/24 of a beat.
Up-down has notes × 2 − 2 steps — the top and bottom notes are not repeated when the direction turns. The octave range stacks whole copies of the chord rather than interleaving.
The arpeggiator is the one section that needs musical time. It reads the host's tempo; a host that never sets one gets 120 BPM.
- Delay — three types including ping-pong, twenty time divisions, feedback, tone, spread, dry/wet
- Chorus — three types, delay time, depth, rate, feedback, level
- Equaliser — a parametric band: tone, frequency, level (±25 dB), Q
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Effect unit — one slot, ten types: three distortions (
a.d.1,a.d.2,d.d.), a decimator, a ring modulator, a compressor, and four phasers
The effect unit is defined primarily from direct measurement.
Operation
Sound design
Technical reference