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Refine Drum Synthesis Engine with Analog Modeling and Master Saturation #31

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17 changes: 8 additions & 9 deletions src/logic/DrumMachine.ts
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Expand Up @@ -40,7 +40,8 @@ export class DrumMachine {

constructor() {
this.comp = new Tone.Compressor(-24, 4)
this.shaper = new Tone.WaveShaper(this.makeDistortionCurve(15))
this.shaper = new Tone.WaveShaper(this.makeDistortionCurve(20))
this.shaper.oversample = '4x'
this.output = new Tone.Gain(1)
this.outputKick = new Tone.Gain(1)
this.outputSnare = new Tone.Gain(1)
Expand All @@ -50,14 +51,12 @@ export class DrumMachine {

this.comp.chain(this.shaper, this.output, Tone.Destination)

// Let's bypass compression for individual drum channels for now,
// to simplify routing and allow strict analog synth modeling.
// We'll route them directly to destination or output
this.outputKick.connect(Tone.Destination)
this.outputSnare.connect(Tone.Destination)
this.outputHihat.connect(Tone.Destination)
this.outputOpenHat.connect(Tone.Destination)
this.outputClap.connect(Tone.Destination)
// Route individual drum channels to the master compressor for "glue" effect
this.outputKick.connect(this.comp)
this.outputSnare.connect(this.comp)
this.outputHihat.connect(this.comp)
this.outputOpenHat.connect(this.comp)
this.outputClap.connect(this.comp)

this.kit808 = {
kick: new TR808Kick(this.outputKick),
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10 changes: 7 additions & 3 deletions src/logic/drums/TR808Clap.ts
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Expand Up @@ -12,15 +12,18 @@ export class TR808Clap {

trigger(time: number, pitch: number, decay: number) {
const noiseSrc = new Tone.BufferSource(this.noiseBuffer);
const bpf = new Tone.Filter(1000 + pitch * 1000, "bandpass");
// Micro-randomization: Filter Cutoff (+/- 2%)
const cutoff = (1000 + pitch * 1000) * (1 + (Math.random() * 0.04 - 0.02));
const bpf = new Tone.Filter(cutoff, "bandpass");
const gain = new Tone.Gain(0).connect(this.destination);

noiseSrc.connect(bpf);
bpf.connect(gain);

// Triple attack "snaps"
const snapCount = 3;
const snapInterval = 0.01;
// Micro-randomization: Snap Interval (+/- 2ms)
const snapInterval = 0.01 + (Math.random() * 0.004 - 0.002);
for (let i = 0; i < snapCount; i++) {
const snapTime = time + i * snapInterval;
gain.gain.setValueAtTime(1, snapTime);
Expand All @@ -29,7 +32,8 @@ export class TR808Clap {

// Final decay
const finalDecayStart = time + snapCount * snapInterval;
const decayTime = 0.1 + decay * 0.5;
// Micro-randomization: Decay Time (+/- 2%)
const decayTime = (0.1 + decay * 0.5) * (1 + (Math.random() * 0.04 - 0.02));
gain.gain.setValueAtTime(1, finalDecayStart);
gain.gain.exponentialRampToValueAtTime(0.001, finalDecayStart + decayTime);

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9 changes: 8 additions & 1 deletion src/logic/drums/TR808HiHat.ts
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Expand Up @@ -20,10 +20,16 @@ export class TR808HiHat {
const oscillators = this.frequencies.map(freq => {
const drift = (Math.random() - 0.5) * 4; // Analog drift
const osc = new Tone.Oscillator(freq * pitchMultiplier + drift, "square");
osc.phase = Math.random() * 360; // Analog phase randomization
osc.connect(mixGain);
return osc;
});

// Micro-randomization: Filter Cutoff (+/- 2%)
bpf1.frequency.value = 3440 * (1 + (Math.random() * 0.04 - 0.02));
bpf2.frequency.value = 7100 * (1 + (Math.random() * 0.04 - 0.02));
hpf.frequency.value = 7000 * (1 + (Math.random() * 0.04 - 0.02));

// Routing Graph
// Oscillators -> MixGain -> [BPF1, BPF2] (Parallel) -> EnvGain -> HPF -> Destination
mixGain.connect(bpf1);
Expand All @@ -38,7 +44,8 @@ export class TR808HiHat {
bpf2.Q.value = 1.5;

// Decay: Closed Hat (40-60ms), Open Hat (300-500ms)
const decayTime = isOpen ? (0.3 + decay * 0.2) : (0.04 + decay * 0.02);
// Micro-randomization: Decay Time (+/- 2%)
const decayTime = (isOpen ? (0.3 + decay * 0.2) : (0.04 + decay * 0.02)) * (1 + (Math.random() * 0.04 - 0.02));

// VCA Envelope
envGain.gain.setValueAtTime(1, time);
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3 changes: 2 additions & 1 deletion src/logic/drums/TR808Kick.ts
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Expand Up @@ -7,7 +7,8 @@ export class TR808Kick {
// pitch: 0.5 -> 52.5Hz, maps to 45-60Hz range
const tune = 45 + pitch * 15;
// decay: 0.5 -> 1.7s, maps to 0.4-3.0s range
const decayTime = 0.4 + decay * 2.6;
// Micro-randomization: Decay Time (+/- 2%)
const decayTime = (0.4 + decay * 2.6) * (1 + (Math.random() * 0.04 - 0.02));

// 808 Kick Core: Bridged-T Network emulation
const osc = new Tone.Oscillator(tune, "sine");
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24 changes: 17 additions & 7 deletions src/logic/drums/TR808Snare.ts
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Expand Up @@ -18,8 +18,13 @@ export class TR808Snare {
const toneBalance = pitch;

// 808 Membrane modes: fixed at ~238Hz and ~476Hz according to research
const oscLow = new Tone.Oscillator(238, "sine");
const oscHigh = new Tone.Oscillator(476, "sine");
// Micro-randomization: Pitch Drift (+/- 1Hz)
const lowDrift = (Math.random() * 2 - 1) * 1;
const highDrift = (Math.random() * 2 - 1) * 1;
const oscLow = new Tone.Oscillator(238 + lowDrift, "sine");
const oscHigh = new Tone.Oscillator(476 + highDrift, "sine");
oscLow.phase = Math.random() * 360; // Analog phase randomization
oscHigh.phase = Math.random() * 360;
const gainLow = new Tone.Gain(1 - toneBalance);
const gainHigh = new Tone.Gain(toneBalance);
const masterTonalGain = new Tone.Gain(0);
Expand All @@ -32,26 +37,31 @@ export class TR808Snare {

masterTonalGain.gain.setValueAtTime(1, time);
// Tonal body decay is short (~200ms)
masterTonalGain.gain.exponentialRampToValueAtTime(0.001, time + 0.2);
// Micro-randomization: Tonal Decay (+/- 2%)
const tonalDecay = 0.2 * (1 + (Math.random() * 0.04 - 0.02));
masterTonalGain.gain.exponentialRampToValueAtTime(0.001, time + tonalDecay);

// Snappy Layer
const noiseSrc = new Tone.BufferSource(this.noiseBuffer);
// High-pass filter (>1800Hz) to prevent phase trap with tonal body
const noiseFilter = new Tone.Filter(1800, "highpass");
// Micro-randomization: Filter Cutoff (+/- 2%)
const noiseCutoff = 1800 * (1 + (Math.random() * 0.04 - 0.02));
const noiseFilter = new Tone.Filter(noiseCutoff, "highpass");
const snappyGain = new Tone.Gain(0);

noiseSrc.connect(noiseFilter);
noiseFilter.connect(snappyGain);
snappyGain.connect(this.destination);

// Snappy decay range: 0.25s to 0.4s
const snappyDecay = 0.25 + snappy * 0.15;
// Micro-randomization: Snappy Decay (+/- 2%)
const snappyDecay = (0.25 + snappy * 0.15) * (1 + (Math.random() * 0.04 - 0.02));

snappyGain.gain.setValueAtTime(0.8, time);
snappyGain.gain.exponentialRampToValueAtTime(0.001, time + snappyDecay);

oscLow.start(time).stop(time + 0.2);
oscHigh.start(time).stop(time + 0.2);
oscLow.start(time).stop(time + tonalDecay);
oscHigh.start(time).stop(time + tonalDecay);
noiseSrc.start(time).stop(time + snappyDecay + 0.1);

// Cleanup
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16 changes: 11 additions & 5 deletions src/logic/drums/TR909Kick.ts
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Expand Up @@ -17,18 +17,22 @@ export class TR909Kick {
// pitch: 0.5 -> 50Hz, maps to 45-55Hz
const tune = 45 + pitch * 10;
// decay: 0.5 -> 0.45s, maps to 0.3-0.6s
const decayTime = 0.3 + decay * 0.3;
// Micro-randomization: Decay Time (+/- 2%)
const decayTime = (0.3 + decay * 0.3) * (1 + (Math.random() * 0.04 - 0.02));

// 909 Kick Body: Triangle Oscillator
const bodyOsc = new Tone.Oscillator(tune * 4.7, "triangle");
// Micro-randomization: Pitch Drift (+/- 0.5Hz)
const bodyDrift = (Math.random() * 2 - 1) * 0.5;
const bodyOsc = new Tone.Oscillator(tune * 4.7 + bodyDrift, "triangle");
bodyOsc.phase = Math.random() * 360; // Analog phase randomization
const bodyGain = new Tone.Gain(0);

bodyOsc.connect(bodyGain);
bodyGain.connect(this.destination);

// Aggressive Pitch Envelope: Start at Tune * 4.7 (~235Hz) and drop over 100ms
const startFreq = tune * 4.7;
const endFreq = tune;
const startFreq = tune * 4.7 + bodyDrift;
const endFreq = tune + bodyDrift;

bodyOsc.frequency.setValueAtTime(startFreq, time);
bodyOsc.frequency.exponentialRampToValueAtTime(endFreq, time + 0.1);
Expand All @@ -39,7 +43,9 @@ export class TR909Kick {

// Click Layer (Noise)
const noiseSrc = new Tone.BufferSource(this.noiseBuffer);
const noiseFilter = new Tone.Filter(1000, "highpass"); // HPF > 1kHz to avoid phase trap
// Micro-randomization: Filter Cutoff (+/- 2%)
const noiseCutoff = 1000 * (1 + (Math.random() * 0.04 - 0.02));
const noiseFilter = new Tone.Filter(noiseCutoff, "highpass"); // HPF > 1kHz to avoid phase trap
const noiseGain = new Tone.Gain(0);

noiseSrc.connect(noiseFilter);
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40 changes: 27 additions & 13 deletions src/logic/drums/TR909Snare.ts
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Expand Up @@ -19,42 +19,56 @@ export class TR909Snare {
const freq1 = 160;
const freq2 = 220;

const osc1 = new Tone.Oscillator(freq1 * 2, "triangle");
const osc2 = new Tone.Oscillator(freq2 * 2, "triangle");
// Micro-randomization: Pitch Drift (+/- 1Hz)
const drift1 = (Math.random() * 2 - 1) * 1;
const drift2 = (Math.random() * 2 - 1) * 1;

const osc1 = new Tone.Oscillator((freq1 + drift1) * 2, "triangle");
const osc2 = new Tone.Oscillator((freq2 + drift2) * 2, "triangle");
osc1.phase = Math.random() * 360; // Analog phase randomization
osc2.phase = Math.random() * 360;
const tonalGain = new Tone.Gain(0);

osc1.connect(tonalGain);
osc2.connect(tonalGain);
tonalGain.connect(this.destination);

// 2x Pitch Sweep over 50ms
osc1.frequency.setValueAtTime(freq1 * 2, time);
osc1.frequency.exponentialRampToValueAtTime(freq1, time + 0.05);
osc2.frequency.setValueAtTime(freq2 * 2, time);
osc2.frequency.exponentialRampToValueAtTime(freq2, time + 0.05);
// 2x Pitch Sweep over 30ms (Tweak from 50ms as per research)
const sweepTime = 0.03;
osc1.frequency.setValueAtTime((freq1 + drift1) * 2, time);
osc1.frequency.exponentialRampToValueAtTime(freq1 + drift1, time + sweepTime);
osc2.frequency.setValueAtTime((freq2 + drift2) * 2, time);
osc2.frequency.exponentialRampToValueAtTime(freq2 + drift2, time + sweepTime);

tonalGain.gain.setValueAtTime(1, time);
tonalGain.gain.exponentialRampToValueAtTime(0.001, time + 0.2);
// Micro-randomization: Tonal Decay (+/- 2%)
const tonalDecay = 0.2 * (1 + (Math.random() * 0.04 - 0.02));
tonalGain.gain.exponentialRampToValueAtTime(0.001, time + tonalDecay);

// Snappy Layer
const noiseSrc = new Tone.BufferSource(this.noiseBuffer);
const hpf = new Tone.Filter(1000, "highpass"); // HPF to protect fundamental
// Micro-randomization: Filter Cutoff (+/- 2%)
const hpfCutoff = 1000 * (1 + (Math.random() * 0.04 - 0.02));
const lpfCutoff = (4000 + pitch * 4000) * (1 + (Math.random() * 0.04 - 0.02));

const hpf = new Tone.Filter(hpfCutoff, "highpass"); // HPF to protect fundamental
// LPF controlled by 'Tone' (pitch parameter here), range 4kHz to 8kHz
const lpf = new Tone.Filter(4000 + pitch * 4000, "lowpass");
const lpf = new Tone.Filter(lpfCutoff, "lowpass");
const noiseGain = new Tone.Gain(0);

noiseSrc.connect(hpf);
hpf.connect(lpf);
lpf.connect(noiseGain);
noiseGain.connect(this.destination);

const snappyDecay = 0.1 + snappy * 0.4;
// Micro-randomization: Snappy Decay (+/- 2%)
const snappyDecay = (0.1 + snappy * 0.4) * (1 + (Math.random() * 0.04 - 0.02));

noiseGain.gain.setValueAtTime(0.7, time);
noiseGain.gain.exponentialRampToValueAtTime(0.001, time + snappyDecay);

osc1.start(time).stop(time + 0.2);
osc2.start(time).stop(time + 0.2);
osc1.start(time).stop(time + tonalDecay);
osc2.start(time).stop(time + tonalDecay);
noiseSrc.start(time).stop(time + snappyDecay + 0.1);

osc1.onstop = () => {
Expand Down