Open-vs-close threshold gap (dB, ≥ 0) — the gate closes hysteresisDb below open.
Input level (dB) where the soft knee ends — above it the gate is fully open (unity).
Input level (dB) where the soft knee begins — below it the gate is fully closed.
Attenuation applied when fully closed (dB, ≤ 0; the closed floor).
Downward EXPANSION ratio (≥ 1) — what turns the hard GATE this model otherwise draws
into a genuine, gentler EXPANDER: 1 is off (no expansion at all), a low ratio (e.g.
2:1) is a gentle expander that only nudges the signal down below threshold, a high
ratio (the default) reads as a hard gate. This is the SAME ratio the compressor's
ACT-ABOVE atom carries, mirrored here for the gate's ACT-BELOW atom — see
@freemixer/server's gateStateToNativeDyn, which threads it straight onto
native.setStripDyn's below-mode ratio. The default (GATE_DEFAULT_RATIO in
@freemixer/catalog/gate) is chosen so a freshly-seeded gate reads exactly as hard as
the pre-ratio model did (see that constant's doc for the derivation).
Open reference / comparator level (dB).
A downward gate / expander, in engineering units. The static side is a transfer curve of applied gain (dB) against input level (dB): below the knee the signal is pulled down by
rangeDb(the closed floor), above it the gain is unity (0 dB, open), and the soft knee ramps betweenkneeStartDb(fully closed) andkneeEndDb(fully open).thresholdDbis the open reference the DSP comparator uses;hysteresisDbis the open-vs-close gap (the gate closes atthresholdDb − hysteresisDb). The dynamic side is the usual attack / hold / release envelope. The transfer geometry + seed defaults live in@freemixer/catalog/gate(gateGainDb/defaultGateState/normalizeGate), whoseGateStateis structurally this one — the curve maths stay in the dependency-free catalog, alongside the EQ curve.