86 lines
3 KiB
Text
86 lines
3 KiB
Text
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// eoc-master.dsp — Master bus effect for the EOC rack.
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//
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// Parameters (4):
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// gain [1.0, 0-2] output gain multiplier
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// width [1.0, 0-2] stereo width: 0=mono, 1=normal, 2=extra-wide
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// limiter_thresh [-1.0, -12 to 0] brick-wall limiter threshold (dB)
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// dc_block [1] nentry: 0=off, 1=on — DC blocking filter
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import("stdfaust.lib");
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// ---------------------------------------------------------------------------
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// UI
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// ---------------------------------------------------------------------------
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gain = hslider("gain", 1.0, 0, 2, 0.001);
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width = hslider("width", 1.0, 0, 2, 0.001);
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limiter_thresh = hslider("limiter_thresh[unit:dB]", -1.0, -12, 0, 0.1);
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dc_block_on = nentry("dc_block", 1, 0, 1, 1);
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// ---------------------------------------------------------------------------
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// DC blocking filter (~10Hz one-pole HP)
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// ---------------------------------------------------------------------------
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dcBlock(on, x) = on * fi.highpass(1, 10.0, x) + (1.0 - on) * x;
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// ---------------------------------------------------------------------------
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// Stereo width via mid-side processing
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// width = 0: mono (side removed)
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// width = 1: original stereo
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// width = 2: enhanced stereo (doubled sides)
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// ---------------------------------------------------------------------------
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stereoWidth(inL, inR) = outL, outR
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with {
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w = width;
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mid = (inL + inR) * 0.5;
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side = (inL - inR) * 0.5;
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outL = mid + side * w;
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outR = mid - side * w;
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};
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// ---------------------------------------------------------------------------
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// Brick-wall limiter: peak-following gain reduction.
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// Uses a leaky envelope follower with fast attack (~0.5ms) and slow release (~100ms).
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// ---------------------------------------------------------------------------
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threshLin = ba.db2linear(limiter_thresh);
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// Leaky-peak envelope follower: exponential release ~100ms
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// Takes a signal, outputs its peak envelope
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releaseCoeff = exp(-1.0 / (float(ma.SR) * 0.100));
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peakEnv = abs : (+ ~ *(releaseCoeff));
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// Gain reduction: clamp to threshold
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limiterGR(env) = threshLin / max(threshLin, env);
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// Stereo limiter: linked L/R gain reduction from max of both peaks
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limiter(inL, inR) = inL * gr, inR * gr
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with {
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envL = peakEnv(inL);
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envR = peakEnv(inR);
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peakStereo = max(envL, envR);
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gr = limiterGR(peakStereo);
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};
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// ---------------------------------------------------------------------------
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// Main process
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// ---------------------------------------------------------------------------
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process(inL, inR) = outL, outR
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with {
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// 1. DC block
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dcL = dcBlock(dc_block_on, inL);
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dcR = dcBlock(dc_block_on, inR);
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// 2. Gain
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gL = dcL * gain;
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gR = dcR * gain;
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// 3. Stereo width
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wL = stereoWidth(gL, gR) : _,!;
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wR = stereoWidth(gL, gR) : !,_;
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// 4. Limiter
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outL = limiter(wL, wR) : _,!;
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outR = limiter(wL, wR) : !,_;
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};
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