<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      user-select: none;
    }

    body {
      background: transparent;
      color: #1e2945;
      padding: 8px;
      display: flex;
      flex-direction: column;
      gap: 8px;
      min-height: 100%;
    }

    .panels-row {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
      width: 100%;
    }

    .knee-panel {
      flex: 1 1 calc(50% - 4px);
      min-width: 280px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
    }

    .panel-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      margin-bottom: 4px;
      padding: 0 4px;
    }

    .panel-title {
      font-size: 14px;
      font-weight: 700;
      color: #0f172a;
    }

    .panel-tag {
      font-size: 11px;
      font-weight: 600;
      padding: 2px 6px;
      border-radius: 4px;
      background: #e2e8f0;
      color: #475569;
    }

    .panel-tag.soft {
      background: #e0f2fe;
      color: #0369a1;
    }

    .svg-container {
      width: 100%;
      max-width: 320px;
      aspect-ratio: 1.15;
    }

    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    .ctrl-bar {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 6px 12px;
      font-size: 13px;
      font-weight: 600;
    }

    .slider-wrap {
      flex: 1;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    input[type="range"] {
      flex: 1;
      accent-color: #22b7ff;
      cursor: pointer;
      height: 6px;
    }

    .val-badge {
      display: inline-block;
      min-width: 68px;
      text-align: right;
      font-variant-numeric: tabular-nums;
      color: #0369a1;
    }

    .gr-text {
      font-size: 12px;
      color: #64748b;
      font-variant-numeric: tabular-nums;
    }

    .gr-val {
      font-weight: 700;
      color: #d97706;
    }

    .grid-line {
      stroke: #e2e8f0;
      stroke-dasharray: 2, 2;
      stroke-width: 1;
    }

    .axis-text {
      font-size: 9px;
      fill: #64748b;
      font-weight: 500;
    }

    .axis-title {
      font-size: 10px;
      fill: #334155;
      font-weight: 700;
    }
  </style>
</head>
<body>

  <div class="ctrl-bar">
    <div class="slider-wrap">
      <span style="white-space:nowrap;font-size:12px;">Input Level:</span>
      <input type="range" id="inSlider" min="-36" max="0" value="-16" step="0.5">
      <span class="val-badge" id="inVal">-16.0 dB</span>
    </div>
  </div>

  <div class="panels-row">
    
    <div class="knee-panel">
      <div class="panel-header">
        <span class="panel-title">Hard Knee</span>
        <span class="gr-text">GR: <span class="gr-val" id="hardGR">0.0 dB</span></span>
      </div>
      <div class="svg-container">
        <svg viewBox="0 0 240 210" id="hardSvg">
          
          <line x1="35" y1="20" x2="225" y2="20" class="grid-line" />
          <line x1="35" y1="67" x2="225" y2="67" class="grid-line" />
          <line x1="35" y1="115" x2="225" y2="115" class="grid-line" />
          <line x1="35" y1="162" x2="225" y2="162" class="grid-line" />
          <line x1="35" y1="210" x2="225" y2="210" class="grid-line" />

          <line x1="35" y1="20" x2="35" y2="210" class="grid-line" />
          <line x1="82.5" y1="20" x2="82.5" y2="210" class="grid-line" />
          <line x1="130" y1="20" x2="130" y2="210" class="grid-line" />
          <line x1="177.5" y1="20" x2="177.5" y2="210" class="grid-line" />
          <line x1="225" y1="20" x2="225" y2="210" class="grid-line" />

          
          <line x1="130" y1="20" x2="130" y2="210" stroke="#94a3b8" stroke-dasharray="3,3" stroke-width="1.2" />

          
          <line x1="35" y1="210" x2="225" y2="20" stroke="#cbd5e1" stroke-width="1.5" stroke-dasharray="4,4" />
          <text x="75" y="150" fill="#94a3b8" font-size="10" font-weight="600" transform="rotate(-45 75 150)">1:1 (No GR)</text>

          
          
          <polyline points="35,210 130,115 225,91.25" fill="none" stroke="#1e2945" stroke-width="3" stroke-linecap="round" stroke-linejoin="round" />

          
          <circle cx="130" cy="115" r="4" fill="#0f172a" />
          <text x="130" y="132" text-anchor="middle" font-size="10" font-weight="700" fill="#0f172a">Threshold: -18 dB</text>
          <text x="195" y="78" fill="#0f172a" font-size="10" font-weight="700">4:1 Ratio</text>

          
          <text x="30" y="213" text-anchor="end" class="axis-text">-36</text>
          <text x="30" y="118" text-anchor="end" class="axis-text">-18</text>
          <text x="30" y="24" text-anchor="end" class="axis-text">0</text>
          <text x="35" y="222" text-anchor="middle" class="axis-text">-36</text>
          <text x="130" y="222" text-anchor="middle" class="axis-text">-18</text>
          <text x="225" y="222" text-anchor="middle" class="axis-text">0</text>

          <text x="130" y="234" text-anchor="middle" class="axis-title">Input (dBFS)</text>
          <text x="12" y="115" text-anchor="middle" class="axis-title" transform="rotate(-90 12 115)">Output (dBFS)</text>

          
          <circle id="hardMarker" cx="130" cy="115" r="5" fill="#22b7ff" stroke="#ffffff" stroke-width="2" />
        </svg>
      </div>
    </div>

    
    <div class="knee-panel">
      <div class="panel-header">
        <span class="panel-title">Soft Knee</span>
        <span class="gr-text">GR: <span class="gr-val" id="softGR">0.0 dB</span></span>
      </div>
      <div class="svg-container">
        <svg viewBox="0 0 240 210" id="softSvg">
          
          
          <rect x="98.33" y="20" width="63.34" height="190" fill="#22b7ff" fill-opacity="0.12" />
          <line x1="98.33" y1="20" x2="98.33" y2="210" stroke="#22b7ff" stroke-width="1" stroke-dasharray="2,2" />
          <line x1="161.67" y1="20" x2="161.67" y2="210" stroke="#22b7ff" stroke-width="1" stroke-dasharray="2,2" />

          
          <line x1="35" y1="20" x2="225" y2="20" class="grid-line" />
          <line x1="35" y1="67" x2="225" y2="67" class="grid-line" />
          <line x1="35" y1="115" x2="225" y2="115" class="grid-line" />
          <line x1="35" y1="162" x2="225" y2="162" class="grid-line" />
          <line x1="35" y1="210" x2="225" y2="210" class="grid-line" />

          <line x1="35" y1="20" x2="35" y2="210" class="grid-line" />
          <line x1="82.5" y1="20" x2="82.5" y2="210" class="grid-line" />
          <line x1="130" y1="20" x2="130" y2="210" class="grid-line" />
          <line x1="177.5" y1="20" x2="177.5" y2="210" class="grid-line" />
          <line x1="225" y1="20" x2="225" y2="210" class="grid-line" />

          
          <line x1="130" y1="20" x2="130" y2="210" stroke="#94a3b8" stroke-dasharray="3,3" stroke-width="1" />

          
          <line x1="35" y1="210" x2="225" y2="20" stroke="#cbd5e1" stroke-width="1.5" stroke-dasharray="4,4" />

          
          <path id="softCurvePath" d="" fill="none" stroke="#0284c7" stroke-width="3" stroke-linecap="round" />

          
          <text x="130" y="32" text-anchor="middle" font-size="9.5" font-weight="700" fill="#0284c7">12 dB Knee Width</text>
          <text x="130" y="44" text-anchor="middle" font-size="8.5" font-weight="600" fill="#0369a1">(-24 to -12 dBFS)</text>

          <text x="195" y="78" fill="#0284c7" font-size="10" font-weight="700">4:1 Ratio</text>

          
          <text x="30" y="213" text-anchor="end" class="axis-text">-36</text>
          <text x="30" y="118" text-anchor="end" class="axis-text">-18</text>
          <text x="30" y="24" text-anchor="end" class="axis-text">0</text>
          <text x="35" y="222" text-anchor="middle" class="axis-text">-36</text>
          <text x="130" y="222" text-anchor="middle" class="axis-text">-18</text>
          <text x="225" y="222" text-anchor="middle" class="axis-text">0</text>

          <text x="130" y="234" text-anchor="middle" class="axis-title">Input (dBFS)</text>
          <text x="12" y="115" text-anchor="middle" class="axis-title" transform="rotate(-90 12 115)">Output (dBFS)</text>

          
          <circle id="softMarker" cx="130" cy="115" r="5" fill="#0284c7" stroke="#ffffff" stroke-width="2" />
        </svg>
      </div>
    </div>
  </div>

  <script>
    const T = -18;      // Threshold (dBFS)
    const R = 4;        // Ratio (4:1)
    const W = 12;       // Knee width (dB)
    const W2 = W / 2;   // 6 dB

    // Coordinates mapping
    // x range: -36 to 0 dBFS -> px 35 to 225 (span 190)
    // y range: -36 to 0 dBFS -> px 210 to 20 (span 190)
    function dbToPxX(db) {
      return 35 + ((db + 36) / 36) * 190;
    }
    function dbToPxY(db) {
      return 210 - ((db + 36) / 36) * 190;
    }

    // Hard Knee function
    function getHardKneeOut(x) {
      if (x <= T) return x;
      return T + (x - T) / R;
    }

    // Soft Knee function (Standard DSP Quadratic Knee)
    function getSoftKneeOut(x) {
      if (x <= T - W2) {
        return x;
      } else if (x >= T + W2) {
        return T + (x - T) / R;
      } else {
        // Quadratic blend zone
        const slopeDiff = (1 / R) - 1;
        const delta = x - T + W2;
        return x + (slopeDiff * delta * delta) / (2 * W);
      }
    }

    // Render continuous soft knee SVG path
    function buildSoftPath() {
      let d = "";
      for (let db = -36; db <= 0; db += 0.5) {
        const out = getSoftKneeOut(db);
        const px = dbToPxX(db);
        const py = dbToPxY(out);
        d += (db === -36 ? `M ${px.toFixed(2)},${py.toFixed(2)}` : ` L ${px.toFixed(2)},${py.toFixed(2)}`);
      }
      document.getElementById('softCurvePath').setAttribute('d', d);
    }
    buildSoftPath();

    // Update markers and readouts on slider input
    const inSlider = document.getElementById('inSlider');
    const inVal = document.getElementById('inVal');
    const hardGR = document.getElementById('hardGR');
    const softGR = document.getElementById('softGR');
    const hardMarker = document.getElementById('hardMarker');
    const softMarker = document.getElementById('softMarker');

    function update() {
      const inDb = parseFloat(inSlider.value);
      inVal.textContent = (inDb >= 0 ? "+" : "") + inDb.toFixed(1) + " dB";

      // Hard Knee
      const hardOut = getHardKneeOut(inDb);
      const hardReduction = inDb - hardOut;
      hardGR.textContent = hardReduction.toFixed(1) + " dB";
      hardMarker.setAttribute('cx', dbToPxX(inDb).toFixed(2));
      hardMarker.setAttribute('cy', dbToPxY(hardOut).toFixed(2));

      // Soft Knee
      const softOut = getSoftKneeOut(inDb);
      const softReduction = inDb - softOut;
      softGR.textContent = softReduction.toFixed(1) + " dB";
      softMarker.setAttribute('cx', dbToPxX(inDb).toFixed(2));
      softMarker.setAttribute('cy', dbToPxY(softOut).toFixed(2));
    }

    inSlider.addEventListener('input', update);
    update();
  </script>
</body>
</html>

Compressor Parameters: Threshold, Ratio, Attack, and Release

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="1:1">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      padding: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      user-select: none;
    }

    .toggles {
      display: flex;
      width: 100%;
      max-width: 440px;
      gap: 6px;
      margin-bottom: 8px;
    }

    .toggle-btn {
      flex: 1;
      border: 1px solid #d1d5db;
      background: #f8fafc;
      padding: 7px 6px;
      border-radius: 6px;
      font-size: 11px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      text-align: center;
      line-height: 1.3;
      transition: background 0.2s, border-color 0.2s, color 0.2s;
    }

    .toggle-btn.active {
      background: #0284c7;
      color: #ffffff;
      border-color: #0284c7;
    }

    .diagram-area {
      position: relative;
      width: 100%;
      max-width: 440px;
      flex: 1;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 6px 8px;
    }

    .track {
      position: relative;
      width: 100%;
      height: 30%;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }

    .track-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 11px;
      font-weight: 700;
      color: #64748b;
      margin-bottom: 2px;
      padding: 0 4px;
    }

    .track-header .badge {
      font-size: 10px;
      padding: 1px 5px;
      border-radius: 4px;
      font-weight: 600;
    }

    .badge-blue { background: #e0f2fe; color: #0284c7; }
    .badge-orange { background: #ffedd5; color: #ea580c; }
    .badge-green { background: #dcfce7; color: #16a34a; }

    svg.wave-canvas {
      width: 100%;
      height: 60px;
      overflow: visible;
    }

    .center-line {
      stroke: #cbd5e1;
      stroke-dasharray: 3 3;
      stroke-width: 1;
    }

    .thresh-line {
      stroke: #ef4444;
      stroke-dasharray: 2 2;
      stroke-width: 1;
    }

    .playhead-line {
      position: absolute;
      top: 0;
      bottom: 0;
      width: 1.5px;
      background: #2563eb;
      box-shadow: 0 0 4px rgba(37,99,235,0.4);
      pointer-events: none;
      z-index: 10;
      left: 10%;
    }

    .time-scale {
      display: flex;
      justify-content: space-between;
      font-size: 9px;
      color: #94a3b8;
      padding: 2px 4px 0;
      border-top: 1px solid #e2e8f0;
      margin-top: 2px;
    }

    .visual-note {
      font-size: 11px;
      font-weight: 600;
      text-align: center;
      color: #334155;
      margin-top: 6px;
      height: 18px;
    }
  </style>
</head>
<body>

  <div class="toggles">
    <button id="btnSlow" class="toggle-btn active" onclick="setMode('slow')">
      Slow Attack (30ms)<br>Fast Release (50ms)
    </button>
    <button id="btnFast" class="toggle-btn" onclick="setMode('fast')">
      Fast Attack (0.5ms)<br>Fast Release (20ms)
    </button>
  </div>

  <div class="diagram-area" id="stage">
    <div class="playhead-line" id="playhead"></div>

    
    <div class="track">
      <div class="track-header">
        <span>Raw Input (Snare Hit)</span>
        <span class="badge badge-blue">Transient + Body</span>
      </div>
      <svg class="wave-canvas" viewBox="0 0 400 60" preserveAspectRatio="none">
        <line x1="0" y1="30" x2="400" y2="30" class="center-line" />
        <line x1="0" y1="12" x2="400" y2="12" class="thresh-line" />
        <line x1="0" y1="48" x2="400" y2="48" class="thresh-line" />
        <path id="rawWave" fill="rgba(2, 132, 199, 0.2)" stroke="#0284c7" stroke-width="1.5" />
      </svg>
    </div>

    
    <div class="track">
      <div class="track-header">
        <span>Gain Reduction (GR)</span>
        <span class="badge badge-orange" id="grBadge">Slow clamp</span>
      </div>
      <svg class="wave-canvas" viewBox="0 0 400 60" preserveAspectRatio="none">
        <line x1="0" y1="8" x2="400" y2="8" stroke="#cbd5e1" stroke-width="1" />
        <text x="5" y="18" fill="#94a3b8" font-size="8" font-weight="600">0 dB</text>
        <text x="5" y="52" fill="#ea580c" font-size="8" font-weight="600">-12 dB</text>
        <path id="grWave" fill="rgba(234, 88, 12, 0.15)" stroke="#ea580c" stroke-width="2" />
      </svg>
    </div>

    
    <div class="track">
      <div class="track-header">
        <span>Output Waveform</span>
        <span class="badge badge-green" id="outBadge">Punch preserved</span>
      </div>
      <svg class="wave-canvas" viewBox="0 0 400 60" preserveAspectRatio="none">
        <line x1="0" y1="30" x2="400" y2="30" class="center-line" />
        <line x1="0" y1="12" x2="400" y2="12" class="thresh-line" />
        <line x1="0" y1="48" x2="400" y2="48" class="thresh-line" />
        <path id="outWave" fill="rgba(22, 163, 74, 0.2)" stroke="#16a34a" stroke-width="1.5" />
      </svg>
    </div>

    <div class="time-scale">
      <span>0 ms (Hit)</span>
      <span>50 ms</span>
      <span>100 ms</span>
      <span>150 ms</span>
      <span>200 ms</span>
    </div>
  </div>

  <div class="visual-note" id="noteText">Transient punches through; body is controlled.</div>

  <script>
    let currentMode = 'slow';
    const N = 200;
    const width = 400;
    const midY = 30;

    // Generate Drum Waveform Envelope & Oscillation
    // Transient at x = 30..60 (peak ~26px amp), Ring/Body x = 60..250
    function getInputEnvelope(x) {
      if (x < 25) return 0;
      if (x <= 40) return (x - 25) / 15; // fast rising transient
      if (x <= 75) return 1.0 - 0.65 * ((x - 40) / 35); // drops to body level (0.35)
      if (x <= 320) return 0.35 * Math.exp(-(x - 75) / 110); // ring decay
      return 0;
    }

    function getAudioSample(x) {
      const env = getInputEnvelope(x);
      if (env === 0) return 0;
      // High frequency transient pop morphing into fundamental ring
      const freq = x < 55 ? 0.9 : 0.45;
      return env * Math.sin((x - 25) * freq);
    }

    function getGainReduction(x, mode) {
      if (x < 25) return 0; // 0 = no reduction (0dB), 1 = max reduction (-12dB)

      if (mode === 'slow') {
        // Slow attack: lets peak slip through (peaks around x=80), fast release
        if (x < 45) {
          return 0.05 * ((x - 25) / 20); // barely reacts during initial spike
        } else if (x <= 95) {
          return 0.05 + 0.7 * ((x - 45) / 50); // clamps down on sustained body
        } else {
          return Math.max(0, 0.75 * Math.exp(-(x - 95) / 55)); // releases quickly
        }
      } else {
        // Fast attack: immediately clamps down peak (x=27), releases immediately on tail
        if (x < 30) {
          return 0.95 * ((x - 25) / 5); // instant clamp
        } else if (x <= 85) {
          return 0.95 * Math.exp(-(x - 30) / 40); // very fast release pumping
        } else {
          return Math.max(0, 0.25 * Math.exp(-(x - 85) / 35));
        }
      }
    }

    function renderWaves() {
      let rawTop = [], rawBot = [];
      let grPts = [];
      let outTop = [], outBot = [];

      for (let i = 0; i <= N; i++) {
        const x = (i / N) * width;
        const rawAmp = getAudioSample(x) * 26; // max +-26px
        rawTop.push(`${x.toFixed(1)},${(midY - rawAmp).toFixed(1)}`);
        rawBot.unshift(`${x.toFixed(1)},${(midY + rawAmp).toFixed(1)}`);

        // GR curve: top is 8px (0dB), bottom is 50px (-12dB)
        const grFactor = getGainReduction(x, currentMode); // 0..1
        const grY = 8 + grFactor * 42;
        grPts.push(`${x.toFixed(1)},${grY.toFixed(1)}`);

        // Output wave: amplitude multiplied by (1 - grFactor * 0.75)
        const compMultiplier = 1.0 - (grFactor * 0.78);
        const outAmp = rawAmp * compMultiplier;
        outTop.push(`${x.toFixed(1)},${(midY - outAmp).toFixed(1)}`);
        outBot.unshift(`${x.toFixed(1)},${(midY + outAmp).toFixed(1)}`);
      }

      document.getElementById('rawWave').setAttribute('d', `M ${rawTop.join(' L ')} L ${rawBot.join(' L ')} Z`);
      document.getElementById('grWave').setAttribute('d', `M 0,8 L ${grPts.join(' L ')} L 400,8 Z`);
      document.getElementById('outWave').setAttribute('d', `M ${outTop.join(' L ')} L ${outBot.join(' L ')} Z`);
    }

    function setMode(mode) {
      currentMode = mode;
      document.getElementById('btnSlow').classList.toggle('active', mode === 'slow');
      document.getElementById('btnFast').classList.toggle('active', mode === 'fast');

      const grBadge = document.getElementById('grBadge');
      const outBadge = document.getElementById('outBadge');
      const note = document.getElementById('noteText');

      if (mode === 'slow') {
        grBadge.textContent = 'Lagged clamp';
        outBadge.textContent = 'Transient punches through';
        note.textContent = 'Slow attack lets the initial spike pass untouched.';
      } else {
        grBadge.textContent = 'Instant clamp';
        outBadge.textContent = 'Transient flattened';
        note.textContent = 'Fast attack shaves the spike flat; causes pumping.';
      }
      renderWaves();
    }

    // Playhead animation
    let startTime = null;
    const playhead = document.getElementById('playhead');

    function animatePlayhead(ts) {
      if (!startTime) startTime = ts;
      const elapsed = (ts - startTime) % 2400; // 2.4s cycle
      const progress = elapsed / 2400;
      
      // Progress over waveform width
      const pct = Math.min(100, Math.max(0, progress * 100));
      playhead.style.left = `${pct}%`;

      requestAnimationFrame(animatePlayhead);
    }

    renderWaves();
    requestAnimationFrame(animatePlayhead);
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <title>Compressor Dynamics: 3 Stages</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      width: 100%;
      background: #f8fafc;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      padding: 12px;
    }
    .app {
      display: flex;
      flex-direction: column;
      gap: 10px;
      max-width: 580px;
      margin: 0 auto;
    }

    /* Step Navigation */
    .controls {
      display: flex;
      gap: 6px;
      justify-content: center;
      align-items: center;
    }
    .step-btn {
      flex: 1;
      padding: 7px 4px;
      font-size: 12px;
      font-weight: 600;
      border: 1px solid #cbd5e1;
      background: #ffffff;
      color: #64748b;
      border-radius: 6px;
      cursor: pointer;
      text-align: center;
      transition: all 0.25s ease;
      white-space: nowrap;
    }
    .step-btn.active {
      background: #22b7ff;
      color: #ffffff;
      border-color: #0284c7;
      box-shadow: 0 2px 6px rgba(34, 183, 255, 0.35);
    }
    .play-btn {
      width: 32px;
      height: 32px;
      display: flex;
      align-items: center;
      justify-content: center;
      border: 1px solid #cbd5e1;
      background: #ffffff;
      color: #1e2945;
      border-radius: 6px;
      cursor: pointer;
      font-size: 13px;
      flex-shrink: 0;
    }

    /* Main Display Box */
    .stage-card {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 12px 14px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    /* Diagram visual layout */
    .viz-grid {
      display: grid;
      grid-template-columns: 46px 1fr 42px;
      gap: 10px;
      height: 220px;
      position: relative;
    }

    /* dB Scale */
    .scale {
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      font-size: 11px;
      font-weight: 600;
      color: #64748b;
      text-align: right;
      padding-right: 4px;
      border-right: 1px dashed #cbd5e1;
      user-select: none;
    }
    .scale .mark-thresh {
      color: #d97706;
      font-weight: 700;
    }

    /* Waveform Canvas Area */
    .waveform-area {
      position: relative;
      background: #f1f5f9;
      border-radius: 6px;
      overflow: hidden;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    /* Grid lines */
    .grid-line {
      position: absolute;
      left: 0;
      right: 0;
      border-top: 1px dashed #e2e8f0;
      pointer-events: none;
    }
    .thresh-line {
      position: absolute;
      left: 0;
      right: 0;
      top: 44.4%; /* -16 dBFS mapped to 0..-36 range: 16/36 = 44.4% */
      border-top: 2px dashed #f59e0b;
      z-index: 2;
      display: flex;
      justify-content: flex-end;
      padding-right: 6px;
    }
    .thresh-badge {
      background: #fef3c7;
      color: #b45309;
      font-size: 10px;
      font-weight: 700;
      padding: 1px 5px;
      border-radius: 4px;
      transform: translateY(-50%);
    }

    /* Waveform visual */
    svg.wave-svg {
      width: 100%;
      height: 100%;
      position: absolute;
      inset: 0;
    }
    .wave-fill {
      fill: rgba(34, 183, 255, 0.22);
      transition: d 0.35s ease;
    }
    .wave-line {
      fill: none;
      stroke: #0284c7;
      stroke-width: 2.2;
      stroke-linecap: round;
      stroke-linejoin: round;
      transition: d 0.35s ease;
    }
    .wave-gr-overlay {
      fill: rgba(239, 68, 68, 0.25);
      stroke: #ef4444;
      stroke-width: 1.5;
      stroke-dasharray: 3 3;
      transition: opacity 0.35s ease, d 0.35s ease;
    }

    /* Right Meter */
    .meter-col {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 3px;
    }
    .meter-track {
      flex: 1;
      width: 18px;
      background: #e2e8f0;
      border-radius: 4px;
      position: relative;
      overflow: hidden;
      display: flex;
      flex-direction: column;
      justify-content: flex-end;
    }
    .meter-fill {
      width: 100%;
      background: linear-gradient(0deg, #10b981 60%, #22b7ff 80%, #ef4444 100%);
      border-radius: 3px;
      transition: height 0.35s ease;
    }
    .meter-peak-line {
      position: absolute;
      left: 0;
      right: 0;
      height: 2px;
      background: #1e2945;
      transition: bottom 0.35s ease;
    }
    .meter-lbl {
      font-size: 10px;
      font-weight: 700;
      color: #64748b;
      text-transform: uppercase;
    }

    /* Metric Badges Row */
    .metrics-row {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
      margin-top: 2px;
    }
    .metric-box {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 6px;
      padding: 6px 8px;
      text-align: center;
    }
    .metric-label {
      font-size: 10px;
      color: #64748b;
      text-transform: uppercase;
      font-weight: 600;
      margin-bottom: 2px;
    }
    .metric-val {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
    }
    .metric-val.highlight {
      color: #0284c7;
    }
    .metric-val.accent {
      color: #10b981;
    }
  </style>
</head>
<body>
  <div class="app">
    
    <div class="controls">
      <button class="step-btn active" id="btn0">1. Original</button>
      <button class="step-btn" id="btn1">2. Compressed</button>
      <button class="step-btn" id="btn2">3. Make-up Gain</button>
      <button class="play-btn" id="playBtn" title="Auto Play">▶</button>
    </div>

    
    <div class="stage-card">
      <div class="viz-grid">
        
        <div class="scale">
          <span>0 dB</span>
          <span>-6 dB</span>
          <span>-12 dB</span>
          <span class="mark-thresh">-16 dB</span>
          <span>-24 dB</span>
          <span>-30 dB</span>
          <span>-36 dB</span>
        </div>

        
        <div class="waveform-area">
          <div class="thresh-line" id="threshLine">
            <span class="thresh-badge">Threshold -16 dB</span>
          </div>

          <svg class="wave-svg" viewBox="0 0 400 200" preserveAspectRatio="none">
            
            <path id="waveFill" class="wave-fill" d="" />
            
            <path id="grFill" class="wave-gr-overlay" d="" opacity="0" />
            
            <path id="waveLine" class="wave-line" d="" />
            
            <line x1="0" y1="100" x2="400" y2="100" stroke="#cbd5e1" stroke-width="1" stroke-dasharray="2 2" />
          </svg>
        </div>

        
        <div class="meter-col">
          <div class="meter-track">
            <div class="meter-fill" id="meterFill" style="height: 100%;"></div>
            <div class="meter-peak-line" id="peakLine" style="bottom: 100%;"></div>
          </div>
          <span class="meter-lbl" id="meterDb">0 dB</span>
        </div>
      </div>

      
      <div class="metrics-row">
        <div class="metric-box">
          <div class="metric-label">Peak Level</div>
          <div class="metric-val" id="valPeak">0 dBFS</div>
        </div>
        <div class="metric-box">
          <div class="metric-label">Quiet Level</div>
          <div class="metric-val highlight" id="valBody">-30 dBFS</div>
        </div>
        <div class="metric-box">
          <div class="metric-label">Dynamic Range</div>
          <div class="metric-val accent" id="valRange">30 dB</div>
        </div>
      </div>
    </div>
  </div>

  <script src="{{VENDOR_CDN}}/classace-diagram.js"></script>
  <script>
    // Stage configurations:
    // Scale: 0 dBFS = 100% amp (y = 0/200), -36 dBFS = 0% amp (y = 100)
    // dB to amp amplitude mapping (linearized for visual clarity):
    // 0 dBFS -> amp: 94
    // -6 dBFS -> amp: 78
    // -16 dBFS -> amp: 52 (Threshold)
    // -24 dBFS -> amp: 32
    // -30 dBFS -> amp: 16
    // -36 dBFS -> amp: 2

    const stages = [
      {
        peakAmp: 94, // 0 dBFS
        bodyAmp: 16, // -30 dBFS
        grAmp: 0,
        meterPct: 100,
        peakDb: "0 dBFS",
        bodyDb: "-30 dBFS",
        rangeDb: "30 dB",
        meterLabel: "0 dB"
      },
      {
        peakAmp: 78, // -6 dBFS (-6 dB Gain Reduction)
        bodyAmp: 16, // -30 dBFS (quiet unchanged)
        grAmp: 94,   // ghost of original peak
        meterPct: 83,
        peakDb: "-6 dBFS",
        bodyDb: "-30 dBFS",
        rangeDb: "24 dB",
        meterLabel: "-6 dB"
      },
      {
        peakAmp: 94, // 0 dBFS (+6 dB makeup gain)
        bodyAmp: 32, // -24 dBFS (lifted body!)
        grAmp: 0,
        meterPct: 100,
        peakDb: "0 dBFS",
        bodyDb: "-24 dBFS",
        rangeDb: "24 dB",
        meterLabel: "0 dB"
      }
    ];

    function buildWavePath(peakA, bodyA) {
      // Symmetrical envelope across 400px width:
      // Quiet start (0..100), Chorus Peak (130..270), Quiet end (300..400)
      const topPts = [
        [0, 100 - bodyA * 0.9],
        [40, 100 - bodyA * 1.1],
        [80, 100 - bodyA * 0.95],
        [115, 100 - (bodyA + (peakA - bodyA) * 0.4)],
        [150, 100 - peakA * 0.95],
        [180, 100 - peakA],
        [200, 100 - peakA * 0.98],
        [225, 100 - peakA],
        [255, 100 - peakA * 0.92],
        [285, 100 - (bodyA + (peakA - bodyA) * 0.35)],
        [320, 100 - bodyA * 1.05],
        [360, 100 - bodyA * 0.9],
        [400, 100 - bodyA]
      ];

      const botPts = topPts.map(p => [p[0], 200 - p[1]]).reverse();

      // Top line path string
      let topPath = `M ${topPts[0][0]} ${topPts[0][1]}`;
      for (let i = 1; i < topPts.length; i++) {
        topPath += ` L ${topPts[i][0]} ${topPts[i][1]}`;
      }

      // Fill polygon path
      let fillPath = topPath;
      for (let i = 0; i < botPts.length; i++) {
        fillPath += ` L ${botPts[i][0]} ${botPts[i][1]}`;
      }
      fillPath += " Z";

      return { line: topPath, fill: fillPath };
    }

    function buildGRPath(origPeakA, compPeakA) {
      // Shows shaved peak region in Stage 2
      const topO = [
        [125, 100 - compPeakA * 0.9],
        [150, 100 - origPeakA * 0.95],
        [180, 100 - origPeakA],
        [200, 100 - origPeakA * 0.98],
        [225, 100 - origPeakA],
        [255, 100 - origPeakA * 0.92],
        [275, 100 - compPeakA * 0.9]
      ];
      const botC = [
        [275, 100 - compPeakA * 0.9],
        [255, 100 - compPeakA * 0.92],
        [225, 100 - compPeakA],
        [200, 100 - compPeakA * 0.98],
        [180, 100 - compPeakA],
        [150, 100 - compPeakA * 0.95],
        [125, 100 - compPeakA * 0.9]
      ];

      let path = `M ${topO[0][0]} ${topO[0][1]}`;
      for (let i = 1; i < topO.length; i++) path += ` L ${topO[i][0]} ${topO[i][1]}`;
      for (let i = 0; i < botC.length; i++) path += ` L ${botC[i][0]} ${botC[i][1]}`;
      return path + " Z";
    }

    let currentStep = 0;
    let timer = null;

    function renderStage(idx) {
      currentStep = idx;
      const s = stages[idx];

      // Update buttons
      [0, 1, 2].forEach(i => {
        const btn = document.getElementById('btn' + i);
        if (btn) btn.classList.toggle('active', i === idx);
      });

      // Waveform shapes
      const paths = buildWavePath(s.peakAmp, s.bodyAmp);
      document.getElementById('waveLine').setAttribute('d', paths.line);
      document.getElementById('waveFill').setAttribute('d', paths.fill);

      // Gain reduction shaded cap in stage 2
      const grEl = document.getElementById('grFill');
      if (idx === 1) {
        grEl.setAttribute('d', buildGRPath(stages[0].peakAmp, s.peakAmp));
        grEl.setAttribute('opacity', '1');
      } else {
        grEl.setAttribute('opacity', '0');
      }

      // Meter & labels
      document.getElementById('meterFill').style.height = s.meterPct + '%';
      document.getElementById('peakLine').style.bottom = s.meterPct + '%';
      document.getElementById('meterDb').textContent = s.meterLabel;

      document.getElementById('valPeak').textContent = s.peakDb;
      document.getElementById('valBody').textContent = s.bodyDb;
      document.getElementById('valRange').textContent = s.rangeDb;
    }

    function startAuto() {
      if (timer) clearInterval(timer);
      timer = setInterval(() => {
        renderStage((currentStep + 1) % 3);
      }, 3200);
      document.getElementById('playBtn').textContent = '⏸';
    }

    function stopAuto() {
      if (timer) {
        clearInterval(timer);
        timer = null;
      }
      document.getElementById('playBtn').textContent = '▶';
    }

    // Interactive wiring
    [0, 1, 2].forEach(i => {
      const btn = document.getElementById('btn' + i);
      btn.addEventListener('click', () => {
        stopAuto();
        renderStage(i);
      });
    });

    document.getElementById('playBtn').addEventListener('click', () => {
      if (timer) stopAuto();
      else startAuto();
    });

    // Initialize stage 1 and start gentle auto-cycle
    renderStage(0);
    startAuto();
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="1:1">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8fafc;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
      user-select: none;
    }
    .wrapper {
      width: 100%;
      max-width: 440px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 10px;
    }
    /* Ratio Tabs */
    .tabs {
      display: flex;
      gap: 6px;
      width: 100%;
      justify-content: center;
      flex-wrap: wrap;
    }
    .tab-btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      border-radius: 6px;
      padding: 6px 12px;
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      cursor: pointer;
      transition: all 0.2s ease;
    }
    .tab-btn.active {
      background: #22b7ff;
      color: #ffffff;
      border-color: #0284c7;
      box-shadow: 0 2px 4px rgba(34, 183, 255, 0.25);
    }
    /* Graph Container */
    .graph-box {
      width: 100%;
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px;
      box-shadow: 0 1px 3px rgba(0,0,0,0.04);
    }
    svg {
      width: 100%;
      height: auto;
      display: block;
    }
    /* Readout Card */
    .readout {
      width: 100%;
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px 12px;
      font-size: 13px;
      line-height: 1.4;
      display: flex;
      justify-content: space-between;
      align-items: center;
      box-shadow: 0 1px 2px rgba(0,0,0,0.03);
    }
    .readout-item {
      display: flex;
      flex-direction: column;
    }
    .readout-label {
      font-size: 10px;
      font-weight: 700;
      color: #64748b;
      text-transform: uppercase;
      letter-spacing: 0.5px;
    }
    .readout-val {
      font-weight: 700;
      color: #1e2945;
      font-size: 13px;
    }
    .gr-val {
      color: #d97706;
    }
  </style>
</head>
<body>
  <div class="wrapper">
    
    <div class="tabs" role="tablist">
      <button class="tab-btn" onclick="selectRatio('2:1')">2:1</button>
      <button class="tab-btn active" onclick="selectRatio('4:1')">4:1</button>
      <button class="tab-btn" onclick="selectRatio('8:1')">8:1</button>
      <button class="tab-btn" onclick="selectRatio('20:1')">20:1 (Limiter)</button>
    </div>

    
    <div class="graph-box">
      <svg viewBox="0 0 360 330" id="graphSvg">
        <defs>
          
          <marker id="arrow" viewBox="0 0 10 10" refX="5" refY="5" markerWidth="4" markerHeight="4" orient="auto-start-reverse">
            <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#d97706" />
          </marker>
        </defs>

        
        
        
        <g stroke="#f1f5f9" stroke-width="1.5">
          <line x1="45" y1="215" x2="325" y2="215" />
          <line x1="45" y1="145" x2="325" y2="145" />
          <line x1="45" y1="75" x2="325" y2="75" />
          
          <line x1="115" y1="5" x2="115" y2="285" />
          <line x1="185" y1="5" x2="185" y2="285" />
          <line x1="255" y1="5" x2="255" y2="285" />
        </g>

        
        <rect x="185" y="5" width="140" height="280" fill="#22b7ff" fill-opacity="0.04" />

        
        <line x1="45" y1="285" x2="325" y2="285" stroke="#94a3b8" stroke-width="1.5" />
        <line x1="45" y1="5" x2="45" y2="285" stroke="#94a3b8" stroke-width="1.5" />

        
        <line x1="185" y1="5" x2="185" y2="285" stroke="#cbd5e1" stroke-width="1.5" stroke-dasharray="4 3" />

        
        <g font-size="11" fill="#64748b" text-anchor="middle" font-family="system-ui">
          
          <text x="45" y="302">-40</text>
          <text x="115" y="302">-30</text>
          <text x="185" y="302" font-weight="700" fill="#1e2945">-20</text>
          <text x="255" y="302">-10</text>
          <text x="325" y="302">0</text>
          <text x="185" y="322" font-weight="600" fill="#1e2945">Input Level (dBFS)</text>

          
          <text x="38" y="289" text-anchor="end">-40</text>
          <text x="38" y="219" text-anchor="end">-30</text>
          <text x="38" y="149" text-anchor="end" font-weight="700" fill="#1e2945">-20</text>
          <text x="38" y="79" text-anchor="end">-10</text>
          <text x="38" y="9" text-anchor="end">0</text>
        </g>
        <text transform="rotate(-90)" x="-145" y="12" font-size="11" font-weight="600" fill="#1e2945" text-anchor="middle" font-family="system-ui">Output (dBFS)</text>

        
        <line x1="45" y1="285" x2="325" y2="5" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="5 4" />
        <text x="300" y="22" font-size="10" fill="#94a3b8" font-weight="600">1:1</text>

        
        
        <line x1="45" y1="285" x2="185" y2="145" stroke="#64748b" stroke-width="2.5" />

        
        <line id="curve-2:1" x1="185" y1="145" x2="325" y2="75" stroke="#cbd5e1" stroke-width="2" />
        <line id="curve-4:1" x1="185" y1="145" x2="325" y2="110" stroke="#cbd5e1" stroke-width="2" />
        <line id="curve-8:1" x1="185" y1="145" x2="325" y2="127.5" stroke="#cbd5e1" stroke-width="2" />
        <line id="curve-20:1" x1="185" y1="145" x2="325" y2="138" stroke="#cbd5e1" stroke-width="2" />

        
        <line id="active-curve" x1="185" y1="145" x2="325" y2="110" stroke="#22b7ff" stroke-width="4" stroke-linecap="round" />

        
        <circle cx="185" cy="145" r="4.5" fill="#1e2945" />
        <text x="180" y="135" font-size="10" font-weight="700" fill="#1e2945" text-anchor="end">Threshold (-20 dBFS)</text>

        
        
        <g id="indicatorGroup">
          
          <line x1="269" y1="285" x2="269" y2="61" stroke="#cbd5e1" stroke-width="1" stroke-dasharray="2 2" />
          
          
          <circle cx="269" cy="61" r="3" fill="#94a3b8" />
          
          
          <line id="grLine" x1="269" y1="61" x2="269" y2="124" stroke="#d97706" stroke-width="2.5" marker-end="url(#arrow)" />

          
          <line id="outLine" x1="45" y1="124" x2="269" y2="124" stroke="#22b7ff" stroke-width="1" stroke-dasharray="3 3" />

          
          <circle id="activePoint" cx="269" cy="124" r="5" fill="#22b7ff" stroke="#ffffff" stroke-width="2" />
        </g>
      </svg>
    </div>

    
    <div class="readout" id="readoutBox">
      <div class="readout-item">
        <span class="readout-label">Input (+12 dB over)</span>
        <span class="readout-val">-8 dBFS</span>
      </div>
      <div class="readout-item">
        <span class="readout-label">Output</span>
        <span class="readout-val" id="outVal" style="color:#0284c7">-17 dBFS</span>
      </div>
      <div class="readout-item" style="text-align: right;">
        <span class="readout-label">Gain Reduction</span>
        <span class="readout-val gr-val" id="grVal">-9 dB</span>
      </div>
    </div>
  </div>

  <script>
    const ratioData = {
      '2:1': {
        slope: 0.5,
        endY: 75,       // y = -20 + 20 * 0.5 = -10 dBFS -> SVG Y = 5 + 10 * 7 = 75
        testY: 103,     // y = -20 + 12 * 0.5 = -14 dBFS -> SVG Y = 5 + 14 * 7 = 103
        outText: '-14 dBFS',
        grText: '-6 dB'
      },
      '4:1': {
        slope: 0.25,
        endY: 110,      // y = -20 + 20 * 0.25 = -15 dBFS -> SVG Y = 5 + 15 * 7 = 110
        testY: 124,     // y = -20 + 12 * 0.25 = -17 dBFS -> SVG Y = 5 + 17 * 7 = 124
        outText: '-17 dBFS',
        grText: '-9 dB'
      },
      '8:1': {
        slope: 0.125,
        endY: 127.5,    // y = -20 + 20 * 0.125 = -17.5 dBFS -> SVG Y = 5 + 17.5 * 7 = 127.5
        testY: 134.5,   // y = -20 + 12 * 0.125 = -18.5 dBFS -> SVG Y = 5 + 18.5 * 7 = 134.5
        outText: '-18.5 dBFS',
        grText: '-10.5 dB'
      },
      '20:1': {
        slope: 0.05,
        endY: 138,      // y = -20 + 20 * 0.05 = -19 dBFS -> SVG Y = 5 + 19 * 7 = 138
        testY: 140.8,   // y = -20 + 12 * 0.05 = -19.4 dBFS -> SVG Y = 5 + 19.4 * 7 = 140.8
        outText: '-19.4 dBFS',
        grText: '-11.4 dB'
      }
    };

    function selectRatio(ratioKey) {
      // Update Tab Styles
      const buttons = document.querySelectorAll('.tab-btn');
      buttons.forEach(btn => {
        if (btn.textContent.startsWith(ratioKey)) {
          btn.classList.add('active');
        } else {
          btn.classList.remove('active');
        }
      });

      // Update Curve Coordinates
      const data = ratioData[ratioKey];
      const activeCurve = document.getElementById('active-curve');
      activeCurve.setAttribute('x2', '325');
      activeCurve.setAttribute('y2', data.endY);

      // Update Test Point & Gain Reduction Arrow
      const activePoint = document.getElementById('activePoint');
      activePoint.setAttribute('cy', data.testY);

      const outLine = document.getElementById('outLine');
      outLine.setAttribute('y1', data.testY);
      outLine.setAttribute('y2', data.testY);

      const grLine = document.getElementById('grLine');
      grLine.setAttribute('y2', data.testY);

      // Update Readouts
      document.getElementById('outVal').textContent = data.outText;
      document.getElementById('grVal').textContent = data.grText;
    }
  </script>
</body>
</html>

MUSTECH-3.6

Aligned learning resources

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