diff --git a/README.md b/README.md
index e88516b..73b5d33 100644
--- a/README.md
+++ b/README.md
@@ -55,6 +55,69 @@ Opens on http://localhost:8080
 4. Keep all DSP code, helpers, and types in the same file
 5. Register in `src/lib/audio/engines/registry.ts`
 
+### Adding CSound-Based Synthesis Engines
+
+For complex DSP algorithms, you can leverage CSound's powerful audio language:
+
+1. Create a single file in `src/lib/audio/engines/` extending the `CsoundEngine<ParamsType>` abstract class
+2. Define a TypeScript interface for your parameters
+3. Implement required methods:
+   - `getName()`: Engine display name
+   - `getDescription()`: Brief description
+   - `getType()`: Return `'generative'`, `'sample'`, or `'input'`
+   - `getOrchestra()`: Return CSound orchestra code as a string
+   - `getParametersForCsound(params)`: Map TypeScript params to CSound channel parameters
+   - `randomParams(pitchLock?)`: Generate random parameter values
+   - `mutateParams(params, mutationAmount?, pitchLock?)`: Mutate existing parameters
+4. Keep all enums, interfaces, and helper logic in the same file
+5. Register in `src/lib/audio/engines/registry.ts`
+
+**CSound Orchestra Guidelines:**
+- Use `instr 1` as your main instrument
+- Read parameters via `chnget "paramName"`
+- Duration is available as `p3`
+- Time-based parameters (attack, decay, release) should be ratios (0-1) scaled by `p3`
+- Output stereo audio with `outs aLeft, aRight`
+- The base class handles WAV parsing, normalization, and fade-in
+
+**Example:**
+```typescript
+import { CsoundEngine, type CsoundParameter } from './base/CsoundEngine';
+
+interface MyParams {
+  frequency: number;
+  resonance: number;
+}
+
+export class MyEngine extends CsoundEngine<MyParams> {
+  getName() { return 'My Engine'; }
+  getDescription() { return 'Description'; }
+  getType() { return 'generative' as const; }
+
+  protected getOrchestra(): string {
+    return `
+instr 1
+  iFreq chnget "frequency"
+  iRes chnget "resonance"
+  aNoise noise 1, 0
+  aOut butterbp aNoise, iFreq, iRes
+  outs aOut, aOut
+endin
+`;
+  }
+
+  protected getParametersForCsound(params: MyParams): CsoundParameter[] {
+    return [
+      { channelName: 'frequency', value: params.frequency },
+      { channelName: 'resonance', value: params.resonance }
+    ];
+  }
+
+  randomParams() { /* ... */ }
+  mutateParams(params, amount = 0.15) { /* ... */ }
+}
+```
+
 ### Adding Audio Processors
 
 1. Create a single file in `src/lib/audio/processors/` implementing the `AudioProcessor` interface
diff --git a/src/App.svelte b/src/App.svelte
index 5d1668c..14cde93 100644
--- a/src/App.svelte
+++ b/src/App.svelte
@@ -9,7 +9,7 @@
   import type { EngineType } from "./lib/audio/engines/base/SynthEngine";
   import { AudioService } from "./lib/audio/services/AudioService";
   import { downloadWAV } from "./lib/audio/utils/WAVEncoder";
-  import { loadVolume, saveVolume, loadDuration, saveDuration, loadPitchLockEnabled, savePitchLockEnabled, loadPitchLockFrequency, savePitchLockFrequency } from "./lib/utils/settings";
+  import { loadVolume, saveVolume, loadDuration, saveDuration, loadPitchLockEnabled, savePitchLockEnabled, loadPitchLockFrequency, savePitchLockFrequency, loadExpandedCategories, saveExpandedCategories } from "./lib/utils/settings";
   import { cropAudio, cutAudio, processSelection } from "./lib/audio/utils/AudioEdit";
   import { generateRandomColor } from "./lib/utils/colors";
   import { getRandomProcessor } from "./lib/audio/processors/registry";
@@ -19,6 +19,7 @@
   import { createKeyboardHandler } from "./lib/utils/keyboard";
   import { parseFrequencyInput, formatFrequency } from "./lib/utils/pitch";
   import { UndoManager, type AudioState } from "./lib/utils/UndoManager";
+  import type { EngineCategory } from "./lib/audio/engines/base/SynthEngine";
 
   let currentEngineIndex = $state(0);
   const engine = $derived(engines[currentEngineIndex]);
@@ -46,6 +47,7 @@
   let selectionEnd = $state<number | null>(null);
   let canUndo = $state(false);
   let sidebarOpen = $state(false);
+  let expandedCategories = $state<Set<string>>(loadExpandedCategories());
 
   const showDuration = $derived(engineType !== 'sample');
   const showRandomButton = $derived(engineType === 'generative');
@@ -74,6 +76,33 @@
     savePitchLockFrequency(pitchLockFrequency);
   });
 
+  $effect(() => {
+    saveExpandedCategories(expandedCategories);
+  });
+
+  // Group engines by category
+  const enginesByCategory = $derived.by(() => {
+    const grouped = new Map<EngineCategory, typeof engines>();
+    for (const engine of engines) {
+      const category = engine.getCategory();
+      if (!grouped.has(category)) {
+        grouped.set(category, []);
+      }
+      grouped.get(category)!.push(engine);
+    }
+    return grouped;
+  });
+
+  function toggleCategory(category: string) {
+    const newSet = new Set(expandedCategories);
+    if (newSet.has(category)) {
+      newSet.delete(category);
+    } else {
+      newSet.add(category);
+    }
+    expandedCategories = newSet;
+  }
+
   onMount(() => {
     audioService.setPlaybackUpdateCallback((position) => {
       playbackPosition = position;
@@ -485,15 +514,32 @@
   <div class="content-wrapper">
     <div class="sidebar" class:open={sidebarOpen}>
       <div class="sidebar-content">
-        {#each engines as currentEngine, index}
-          <button
-            class="engine-button"
-            class:active={currentEngineIndex === index}
-            data-description={currentEngine.getDescription()}
-            onclick={() => switchEngine(index)}
-          >
-            {currentEngine.getName()}
-          </button>
+        {#each Array.from(enginesByCategory.entries()) as [category, categoryEngines]}
+          <div class="category-section">
+            <button
+              class="category-header"
+              class:collapsed={!expandedCategories.has(category)}
+              onclick={() => toggleCategory(category)}
+            >
+              <svg class="category-arrow" width="12" height="12" viewBox="0 0 12 12" fill="none">
+                <path d="M3 4.5L6 7.5L9 4.5" stroke="currentColor" stroke-width="1.5" stroke-linecap="square"/>
+              </svg>
+              <span>{category}</span>
+            </button>
+            {#if expandedCategories.has(category)}
+              {#each categoryEngines as currentEngine}
+                {@const index = engines.indexOf(currentEngine)}
+                <button
+                  class="engine-button"
+                  class:active={currentEngineIndex === index}
+                  data-description={currentEngine.getDescription()}
+                  onclick={() => switchEngine(index)}
+                >
+                  {currentEngine.getName()}
+                </button>
+              {/each}
+            {/if}
+          </div>
         {/each}
       </div>
     </div>
@@ -693,12 +739,50 @@
     border-radius: 0;
   }
 
+  .category-section {
+    display: flex;
+    flex-direction: column;
+  }
+
+  .category-header {
+    display: flex;
+    align-items: center;
+    gap: 0.35rem;
+    font-size: 0.65rem;
+    font-weight: 600;
+    text-transform: uppercase;
+    letter-spacing: 0.05em;
+    padding: 0.5rem 0.5rem;
+    background-color: #1a1a1a;
+    border: none;
+    border-bottom: 1px solid #333;
+    color: #999;
+    text-align: left;
+    cursor: pointer;
+    transition: color 0.2s, background-color 0.2s;
+    flex-shrink: 0;
+  }
+
+  .category-header:hover {
+    color: #ccc;
+    background-color: #222;
+  }
+
+  .category-arrow {
+    transition: transform 0.2s;
+    flex-shrink: 0;
+  }
+
+  .category-header.collapsed .category-arrow {
+    transform: rotate(-90deg);
+  }
+
   .engine-button {
     opacity: 0.7;
     position: relative;
     flex-shrink: 0;
     font-size: 0.75rem;
-    padding: 0.5rem 0.5rem;
+    padding: 0.5rem 0.5rem 0.5rem 1rem;
     white-space: nowrap;
     overflow: hidden;
     text-overflow: ellipsis;
diff --git a/src/lib/audio/engines/AdditiveBass.ts b/src/lib/audio/engines/AdditiveBass.ts
new file mode 100644
index 0000000..a90585e
--- /dev/null
+++ b/src/lib/audio/engines/AdditiveBass.ts
@@ -0,0 +1,228 @@
+import { CsoundEngine, type CsoundParameter } from './base/CsoundEngine';
+import type { PitchLock } from './base/SynthEngine';
+
+interface AdditiveBassParams {
+  baseFreq: number;
+  pitchSweep: number;
+  pitchDecay: number;
+  overtoneAmp: number;
+  overtoneFreqMult: number;
+  noiseAmp: number;
+  noiseDecay: number;
+  filterResonance: number;
+  filterCutoff: number;
+  attack: number;
+  decay: number;
+  waveshape: number;
+  bodyResonance: number;
+  click: number;
+  harmonicSpread: number;
+}
+
+export class AdditiveBass extends CsoundEngine<AdditiveBassParams> {
+  getName(): string {
+    return 'Additive Bass';
+  }
+
+  getDescription(): string {
+    return 'Deep bass drum using additive synthesis with pink noise and waveshaping';
+  }
+
+  getType() {
+    return 'generative' as const;
+  }
+
+  getCategory() {
+    return 'Percussion' as const;
+  }
+
+  protected getOrchestra(): string {
+    return `
+instr 1
+  iBaseFreq chnget "baseFreq"
+  iPitchSweep chnget "pitchSweep"
+  iPitchDecay chnget "pitchDecay"
+  iOvertoneAmp chnget "overtoneAmp"
+  iOvertoneFreqMult chnget "overtoneFreqMult"
+  iNoiseAmp chnget "noiseAmp"
+  iNoiseDecay chnget "noiseDecay"
+  iFilterResonance chnget "filterResonance"
+  iFilterCutoff chnget "filterCutoff"
+  iAttack chnget "attack"
+  iDecay chnget "decay"
+  iWaveshape chnget "waveshape"
+  iBodyResonance chnget "bodyResonance"
+  iClick chnget "click"
+  iHarmonicSpread chnget "harmonicSpread"
+
+  idur = p3
+  iAttackTime = iAttack * idur
+  iDecayTime = iDecay * idur
+  iPitchDecayTime = iPitchDecay * idur
+  iNoiseDecayTime = iNoiseDecay * idur
+
+  ; Pitch envelope: exponential sweep from high to low
+  kPitchEnv expseg iBaseFreq * (1 + iPitchSweep * 3), iPitchDecayTime, iBaseFreq, idur - iPitchDecayTime, iBaseFreq * 0.95
+
+  ; Main amplitude envelope with attack and decay
+  kAmpEnv linseg 0, iAttackTime, 1, iDecayTime, 0.001, 0.001, 0
+  kAmpEnv = kAmpEnv * kAmpEnv
+
+  ; Generate fundamental sine wave
+  aFund oscili 0.7, kPitchEnv
+
+  ; Generate overtone at multiple of fundamental
+  aOvertone oscili iOvertoneAmp, kPitchEnv * iOvertoneFreqMult
+
+  ; Add harmonic spread (additional harmonics)
+  aHarm2 oscili iHarmonicSpread * 0.3, kPitchEnv * 3
+  aHarm3 oscili iHarmonicSpread * 0.2, kPitchEnv * 5
+
+  ; Mix oscillators
+  aMix = aFund + aOvertone + aHarm2 + aHarm3
+
+  ; Apply waveshaping (hyperbolic tangent style)
+  if iWaveshape > 0.1 then
+    aMix = tanh(aMix * (1 + iWaveshape * 3))
+  endif
+
+  ; Generate pink noise
+  aPink pinkish 1
+
+  ; Noise envelope (fast decay)
+  kNoiseEnv expseg 1, iNoiseDecayTime, 0.001, idur - iNoiseDecayTime, 0.001
+  aPinkScaled = aPink * iNoiseAmp * kNoiseEnv
+
+  ; Add noise to mix
+  aMix = aMix + aPinkScaled
+
+  ; Click transient (high frequency burst at start)
+  if iClick > 0.1 then
+    kClickEnv linseg 1, 0.005, 0, idur - 0.005, 0
+    aClick oscili iClick * 0.4, kPitchEnv * 8
+    aMix = aMix + aClick * kClickEnv
+  endif
+
+  ; Apply resonant low-pass filter
+  kFilterFreq = iFilterCutoff * (1 + kPitchEnv / iBaseFreq * 0.5)
+  aFiltered rezzy aMix, kFilterFreq, iFilterResonance
+
+  ; Body resonance (second resonant filter at fundamental)
+  if iBodyResonance > 0.1 then
+    aBodyFilt butterbp aFiltered, kPitchEnv * 0.5, 20
+    aFiltered = aFiltered + aBodyFilt * iBodyResonance
+  endif
+
+  ; Apply main envelope
+  aOut = aFiltered * kAmpEnv * 0.5
+
+  ; Stereo - slightly different phase and detune for right channel
+  kPitchEnvR expseg iBaseFreq * 1.002 * (1 + iPitchSweep * 3), iPitchDecayTime, iBaseFreq * 1.002, idur - iPitchDecayTime, iBaseFreq * 0.952
+
+  aFundR oscili 0.7, kPitchEnvR
+  aOvertoneR oscili iOvertoneAmp, kPitchEnvR * iOvertoneFreqMult
+  aHarm2R oscili iHarmonicSpread * 0.3, kPitchEnvR * 3
+  aHarm3R oscili iHarmonicSpread * 0.2, kPitchEnvR * 5
+
+  aMixR = aFundR + aOvertoneR + aHarm2R + aHarm3R
+
+  if iWaveshape > 0.1 then
+    aMixR = tanh(aMixR * (1 + iWaveshape * 3))
+  endif
+
+  aPinkR pinkish 1
+  aPinkScaledR = aPinkR * iNoiseAmp * kNoiseEnv
+  aMixR = aMixR + aPinkScaledR
+
+  if iClick > 0.1 then
+    aClickR oscili iClick * 0.4, kPitchEnvR * 8
+    aMixR = aMixR + aClickR * kClickEnv
+  endif
+
+  kFilterFreqR = iFilterCutoff * (1 + kPitchEnvR / iBaseFreq * 0.5)
+  aFilteredR rezzy aMixR, kFilterFreqR, iFilterResonance
+
+  if iBodyResonance > 0.1 then
+    aBodyFiltR butterbp aFilteredR, kPitchEnvR * 0.5, 20
+    aFilteredR = aFilteredR + aBodyFiltR * iBodyResonance
+  endif
+
+  aOutR = aFilteredR * kAmpEnv * 0.5
+
+  outs aOut, aOutR
+endin
+`;
+  }
+
+  protected getParametersForCsound(params: AdditiveBassParams): CsoundParameter[] {
+    return [
+      { channelName: 'baseFreq', value: params.baseFreq },
+      { channelName: 'pitchSweep', value: params.pitchSweep },
+      { channelName: 'pitchDecay', value: params.pitchDecay },
+      { channelName: 'overtoneAmp', value: params.overtoneAmp },
+      { channelName: 'overtoneFreqMult', value: params.overtoneFreqMult },
+      { channelName: 'noiseAmp', value: params.noiseAmp },
+      { channelName: 'noiseDecay', value: params.noiseDecay },
+      { channelName: 'filterResonance', value: params.filterResonance },
+      { channelName: 'filterCutoff', value: params.filterCutoff },
+      { channelName: 'attack', value: params.attack },
+      { channelName: 'decay', value: params.decay },
+      { channelName: 'waveshape', value: params.waveshape },
+      { channelName: 'bodyResonance', value: params.bodyResonance },
+      { channelName: 'click', value: params.click },
+      { channelName: 'harmonicSpread', value: params.harmonicSpread },
+    ];
+  }
+
+  randomParams(pitchLock?: PitchLock): AdditiveBassParams {
+    const baseFreq = pitchLock?.enabled ? pitchLock.frequency : this.randomRange(35, 80);
+
+    const overtoneMultChoices = [1.5, 2.0, 2.5, 3.0, 4.0];
+
+    return {
+      baseFreq,
+      pitchSweep: this.randomRange(0.3, 1.0),
+      pitchDecay: this.randomRange(0.02, 0.15),
+      overtoneAmp: this.randomRange(0.2, 0.7),
+      overtoneFreqMult: this.randomChoice(overtoneMultChoices),
+      noiseAmp: this.randomRange(0.05, 0.3),
+      noiseDecay: this.randomRange(0.01, 0.08),
+      filterResonance: this.randomRange(5, 25),
+      filterCutoff: this.randomRange(100, 800),
+      attack: this.randomRange(0.001, 0.02),
+      decay: this.randomRange(0.3, 0.8),
+      waveshape: this.randomRange(0, 0.7),
+      bodyResonance: this.randomRange(0, 0.5),
+      click: this.randomRange(0, 0.6),
+      harmonicSpread: this.randomRange(0, 0.5),
+    };
+  }
+
+  mutateParams(
+    params: AdditiveBassParams,
+    mutationAmount: number = 0.15,
+    pitchLock?: PitchLock
+  ): AdditiveBassParams {
+    const baseFreq = pitchLock?.enabled ? pitchLock.frequency : params.baseFreq;
+    const overtoneMultChoices = [1.5, 2.0, 2.5, 3.0, 4.0];
+
+    return {
+      baseFreq,
+      pitchSweep: this.mutateValue(params.pitchSweep, mutationAmount, 0.1, 1.5),
+      pitchDecay: this.mutateValue(params.pitchDecay, mutationAmount, 0.01, 0.25),
+      overtoneAmp: this.mutateValue(params.overtoneAmp, mutationAmount, 0, 1.0),
+      overtoneFreqMult:
+        Math.random() < 0.1 ? this.randomChoice(overtoneMultChoices) : params.overtoneFreqMult,
+      noiseAmp: this.mutateValue(params.noiseAmp, mutationAmount, 0, 0.5),
+      noiseDecay: this.mutateValue(params.noiseDecay, mutationAmount, 0.005, 0.15),
+      filterResonance: this.mutateValue(params.filterResonance, mutationAmount, 2, 40),
+      filterCutoff: this.mutateValue(params.filterCutoff, mutationAmount, 80, 1200),
+      attack: this.mutateValue(params.attack, mutationAmount, 0.001, 0.05),
+      decay: this.mutateValue(params.decay, mutationAmount, 0.15, 0.95),
+      waveshape: this.mutateValue(params.waveshape, mutationAmount, 0, 1),
+      bodyResonance: this.mutateValue(params.bodyResonance, mutationAmount, 0, 0.8),
+      click: this.mutateValue(params.click, mutationAmount, 0, 0.8),
+      harmonicSpread: this.mutateValue(params.harmonicSpread, mutationAmount, 0, 0.7),
+    };
+  }
+}
diff --git a/src/lib/audio/engines/AdditiveEngine.ts b/src/lib/audio/engines/AdditiveEngine.ts
index 3f6b485..a3206a5 100644
--- a/src/lib/audio/engines/AdditiveEngine.ts
+++ b/src/lib/audio/engines/AdditiveEngine.ts
@@ -80,7 +80,7 @@ export interface AdditiveParams {
 
 export class AdditiveEngine implements SynthEngine<AdditiveParams> {
   getName(): string {
-    return 'Prism';
+    return 'Glass Prism';
   }
 
   getDescription(): string {
@@ -91,6 +91,10 @@ export class AdditiveEngine implements SynthEngine<AdditiveParams> {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Additive' as const;
+  }
+
   generate(params: AdditiveParams, sampleRate: number, duration: number): [Float32Array, Float32Array] {
     const numSamples = Math.floor(sampleRate * duration);
     const leftBuffer = new Float32Array(numSamples);
diff --git a/src/lib/audio/engines/BassDrum.ts b/src/lib/audio/engines/BassDrum.ts
index fc15f53..d062f94 100644
--- a/src/lib/audio/engines/BassDrum.ts
+++ b/src/lib/audio/engines/BassDrum.ts
@@ -57,7 +57,7 @@ interface BassDrumParams {
 
 export class BassDrum implements SynthEngine {
   getName(): string {
-    return 'Kick';
+    return 'Dark Kick';
   }
 
   getDescription(): string {
@@ -68,6 +68,10 @@ export class BassDrum implements SynthEngine {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Percussion' as const;
+  }
+
   randomParams(pitchLock?: PitchLock): BassDrumParams {
     // Choose a kick character/style
     const styleRoll = Math.random();
diff --git a/src/lib/audio/engines/Benjolin.ts b/src/lib/audio/engines/Benjolin.ts
index 5115af3..53d69a8 100644
--- a/src/lib/audio/engines/Benjolin.ts
+++ b/src/lib/audio/engines/Benjolin.ts
@@ -73,6 +73,10 @@ export class Benjolin implements SynthEngine<BenjolinParams> {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Experimental' as const;
+  }
+
   generate(params: BenjolinParams, sampleRate: number, duration: number): [Float32Array, Float32Array] {
     const numSamples = Math.floor(duration * sampleRate);
     const left = new Float32Array(numSamples);
diff --git a/src/lib/audio/engines/DubSiren.ts b/src/lib/audio/engines/DubSiren.ts
index 9242702..3e87fb7 100644
--- a/src/lib/audio/engines/DubSiren.ts
+++ b/src/lib/audio/engines/DubSiren.ts
@@ -67,6 +67,10 @@ export class DubSiren implements SynthEngine<DubSirenParams> {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Experimental' as const;
+  }
+
   generate(params: DubSirenParams, sampleRate: number, duration: number): [Float32Array, Float32Array] {
     const numSamples = Math.floor(sampleRate * duration);
     const leftBuffer = new Float32Array(numSamples);
diff --git a/src/lib/audio/engines/DustNoise.ts b/src/lib/audio/engines/DustNoise.ts
index 4c24c42..71cefd6 100644
--- a/src/lib/audio/engines/DustNoise.ts
+++ b/src/lib/audio/engines/DustNoise.ts
@@ -46,6 +46,10 @@ export class DustNoise implements SynthEngine {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Noise' as const;
+  }
+
   randomParams(pitchLock?: PitchLock): DustNoiseParams {
     const characterBias = Math.random();
 
diff --git a/src/lib/audio/engines/FMTomTom.ts b/src/lib/audio/engines/FMTomTom.ts
new file mode 100644
index 0000000..7ce748b
--- /dev/null
+++ b/src/lib/audio/engines/FMTomTom.ts
@@ -0,0 +1,184 @@
+import { CsoundEngine, type CsoundParameter } from './base/CsoundEngine';
+import type { PitchLock } from './base/SynthEngine';
+
+interface FMTomTomParams {
+  baseFreq: number;
+  pitchBendAmount: number;
+  pitchBendDecay: number;
+  modIndex: number;
+  modRatio: number;
+  noiseHPFreq: number;
+  noiseResonance: number;
+  noiseMix: number;
+  ampAttack: number;
+  ampDecay: number;
+  sustain: number;
+  release: number;
+  tonality: number;
+  stereoDetune: number;
+}
+
+export class FMTomTom extends CsoundEngine<FMTomTomParams> {
+  getName(): string {
+    return 'FM Tom-Tom';
+  }
+
+  getDescription(): string {
+    return 'High-pass filtered noise modulating a sine oscillator with pitch bend envelope simulating tom-tom membrane';
+  }
+
+  getType() {
+    return 'generative' as const;
+  }
+
+  getCategory() {
+    return 'Percussion' as const;
+  }
+
+  protected getOrchestra(): string {
+    return `
+instr 1
+  iBaseFreq chnget "baseFreq"
+  iPitchBendAmount chnget "pitchBendAmount"
+  iPitchBendDecay chnget "pitchBendDecay"
+  iModIndex chnget "modIndex"
+  iModRatio chnget "modRatio"
+  iNoiseHPFreq chnget "noiseHPFreq"
+  iNoiseResonance chnget "noiseResonance"
+  iNoiseMix chnget "noiseMix"
+  iAmpAttack chnget "ampAttack"
+  iAmpDecay chnget "ampDecay"
+  iSustain chnget "sustain"
+  iRelease chnget "release"
+  iTonality chnget "tonality"
+  iStereoDetune chnget "stereoDetune"
+
+  idur = p3
+  iPitchBendTime = iPitchBendDecay * idur
+  iAmpAttackTime = iAmpAttack * idur
+  iAmpDecayTime = iAmpDecay * idur
+  iReleaseTime = iRelease * idur
+
+  ; Pitch bend envelope (simulates drum membrane tightening)
+  ; Starts at higher pitch and decays to base pitch
+  iPitchStart = iBaseFreq * (1 + iPitchBendAmount)
+  kPitchEnv expseg iPitchStart, iPitchBendTime, iBaseFreq, idur - iPitchBendTime, iBaseFreq
+
+  ; Generate high-pass filtered noise for modulation
+  aNoise noise 1, 0
+  aNoiseHP butterhp aNoise, iNoiseHPFreq
+  aNoiseFiltered butterbp aNoiseHP, iNoiseHPFreq * 2, iNoiseResonance
+
+  ; Scale noise for FM modulation
+  aNoiseScaled = aNoiseFiltered * iModIndex * kPitchEnv * iTonality
+
+  ; FM synthesis: noise modulates sine oscillator
+  aModulator oscili iModIndex * kPitchEnv, kPitchEnv * iModRatio
+  aCarrier oscili 0.5, kPitchEnv + aModulator + aNoiseScaled
+
+  ; Add direct noise component for more realistic tom sound
+  aNoiseDirect = aNoiseFiltered * iNoiseMix * 0.3
+
+  ; Mix carrier and noise
+  aMix = aCarrier * (1 - iNoiseMix * 0.5) + aNoiseDirect
+
+  ; Amplitude envelope (ADSR-like with fast attack and decay)
+  kAmpEnv expseg 0.001, iAmpAttackTime, 1, iAmpDecayTime, iSustain, idur - iAmpAttackTime - iAmpDecayTime - iReleaseTime, iSustain, iReleaseTime, 0.001
+
+  ; Apply amplitude envelope
+  aOut = aMix * kAmpEnv
+
+  ; Right channel with stereo detune
+  iBaseFreqR = iBaseFreq * (1 + iStereoDetune * 0.02)
+  iPitchStartR = iBaseFreqR * (1 + iPitchBendAmount)
+  kPitchEnvR expseg iPitchStartR, iPitchBendTime, iBaseFreqR, idur - iPitchBendTime, iBaseFreqR
+
+  aNoiseR noise 1, 0
+  aNoiseHPR butterhp aNoiseR, iNoiseHPFreq * (1 + iStereoDetune * 0.01)
+  aNoiseFilteredR butterbp aNoiseHPR, iNoiseHPFreq * 2 * (1 + iStereoDetune * 0.01), iNoiseResonance
+
+  aNoiseScaledR = aNoiseFilteredR * iModIndex * kPitchEnvR * iTonality
+  aModulatorR oscili iModIndex * kPitchEnvR, kPitchEnvR * iModRatio
+  aCarrierR oscili 0.5, kPitchEnvR + aModulatorR + aNoiseScaledR
+
+  aNoiseDirectR = aNoiseFilteredR * iNoiseMix * 0.3
+  aMixR = aCarrierR * (1 - iNoiseMix * 0.5) + aNoiseDirectR
+  aOutR = aMixR * kAmpEnv
+
+  outs aOut, aOutR
+endin
+`;
+  }
+
+  protected getParametersForCsound(params: FMTomTomParams): CsoundParameter[] {
+    return [
+      { channelName: 'baseFreq', value: params.baseFreq },
+      { channelName: 'pitchBendAmount', value: params.pitchBendAmount },
+      { channelName: 'pitchBendDecay', value: params.pitchBendDecay },
+      { channelName: 'modIndex', value: params.modIndex },
+      { channelName: 'modRatio', value: params.modRatio },
+      { channelName: 'noiseHPFreq', value: params.noiseHPFreq },
+      { channelName: 'noiseResonance', value: params.noiseResonance },
+      { channelName: 'noiseMix', value: params.noiseMix },
+      { channelName: 'ampAttack', value: params.ampAttack },
+      { channelName: 'ampDecay', value: params.ampDecay },
+      { channelName: 'sustain', value: params.sustain },
+      { channelName: 'release', value: params.release },
+      { channelName: 'tonality', value: params.tonality },
+      { channelName: 'stereoDetune', value: params.stereoDetune },
+    ];
+  }
+
+  randomParams(pitchLock?: PitchLock): FMTomTomParams {
+    const baseFreqChoices = [80, 100, 120, 150, 180, 220, 260, 300];
+    const baseFreq = pitchLock?.enabled
+      ? pitchLock.frequency
+      : this.randomChoice(baseFreqChoices) * this.randomRange(0.9, 1.1);
+
+    const modRatios = [0.5, 1, 1.5, 2, 2.5, 3];
+
+    return {
+      baseFreq,
+      pitchBendAmount: this.randomRange(0.2, 0.8),
+      pitchBendDecay: this.randomRange(0.05, 0.2),
+      modIndex: this.randomRange(1, 8),
+      modRatio: this.randomChoice(modRatios),
+      noiseHPFreq: this.randomRange(200, 800),
+      noiseResonance: this.randomRange(20, 100),
+      noiseMix: this.randomRange(0.1, 0.6),
+      ampAttack: this.randomRange(0.001, 0.01),
+      ampDecay: this.randomRange(0.1, 0.3),
+      sustain: this.randomRange(0.2, 0.6),
+      release: this.randomRange(0.2, 0.5),
+      tonality: this.randomRange(0.3, 0.9),
+      stereoDetune: this.randomRange(0, 0.5),
+    };
+  }
+
+  mutateParams(
+    params: FMTomTomParams,
+    mutationAmount: number = 0.15,
+    pitchLock?: PitchLock
+  ): FMTomTomParams {
+    const baseFreq = pitchLock?.enabled ? pitchLock.frequency : params.baseFreq;
+    const modRatios = [0.5, 1, 1.5, 2, 2.5, 3];
+
+    return {
+      baseFreq,
+      pitchBendAmount: this.mutateValue(params.pitchBendAmount, mutationAmount, 0.1, 1),
+      pitchBendDecay: this.mutateValue(params.pitchBendDecay, mutationAmount, 0.02, 0.4),
+      modIndex: this.mutateValue(params.modIndex, mutationAmount, 0.5, 12),
+      modRatio:
+        Math.random() < 0.15 ? this.randomChoice(modRatios) : params.modRatio,
+      noiseHPFreq: this.mutateValue(params.noiseHPFreq, mutationAmount, 100, 1200),
+      noiseResonance: this.mutateValue(params.noiseResonance, mutationAmount, 15, 150),
+      noiseMix: this.mutateValue(params.noiseMix, mutationAmount, 0, 0.8),
+      ampAttack: this.mutateValue(params.ampAttack, mutationAmount, 0.001, 0.02),
+      ampDecay: this.mutateValue(params.ampDecay, mutationAmount, 0.05, 0.5),
+      sustain: this.mutateValue(params.sustain, mutationAmount, 0.1, 0.8),
+      release: this.mutateValue(params.release, mutationAmount, 0.1, 0.7),
+      tonality: this.mutateValue(params.tonality, mutationAmount, 0.1, 1),
+      stereoDetune: this.mutateValue(params.stereoDetune, mutationAmount, 0, 1),
+    };
+  }
+}
diff --git a/src/lib/audio/engines/FeedbackSnare.ts b/src/lib/audio/engines/FeedbackSnare.ts
new file mode 100644
index 0000000..230f7ed
--- /dev/null
+++ b/src/lib/audio/engines/FeedbackSnare.ts
@@ -0,0 +1,247 @@
+import { CsoundEngine, type CsoundParameter } from './base/CsoundEngine';
+import type { PitchLock } from './base/SynthEngine';
+
+interface FeedbackSnareParams {
+  baseFreq: number;
+  tonalDecay: number;
+  noiseDecay: number;
+  toneResonance: number;
+  springDecay: number;
+  springTone: number;
+  pitchBend: number;
+  pitchBendSpeed: number;
+  pulseRate: number;
+  feedbackAmount: number;
+  delayTime: number;
+  crossFeedMix: number;
+  snap: number;
+  brightness: number;
+}
+
+export class FeedbackSnare extends CsoundEngine<FeedbackSnareParams> {
+  getName(): string {
+    return 'Feedback Snare';
+  }
+
+  getDescription(): string {
+    return 'Complex snare using cross-feedback delay network with pulsed noise modulation';
+  }
+
+  getType() {
+    return 'generative' as const;
+  }
+
+  getCategory() {
+    return 'Percussion' as const;
+  }
+
+  protected getOrchestra(): string {
+    return `
+instr 1
+  iBaseFreq chnget "baseFreq"
+  iTonalDecay chnget "tonalDecay"
+  iNoiseDecay chnget "noiseDecay"
+  iToneResonance chnget "toneResonance"
+  iSpringDecay chnget "springDecay"
+  iSpringTone chnget "springTone"
+  iPitchBend chnget "pitchBend"
+  iPitchBendSpeed chnget "pitchBendSpeed"
+  iPulseRate chnget "pulseRate"
+  iFeedbackAmount chnget "feedbackAmount"
+  iDelayTime chnget "delayTime"
+  iCrossFeedMix chnget "crossFeedMix"
+  iSnap chnget "snap"
+  iBrightness chnget "brightness"
+
+  idur = p3
+  iTonalDecayTime = iTonalDecay * idur
+  iNoiseDecayTime = iNoiseDecay * idur
+  iSpringDecayTime = iSpringDecay * idur
+  iPitchBendTime = iPitchBendSpeed * idur
+
+  ; Pitch envelope with bend
+  kPitchEnv expseg iBaseFreq * (1 + iPitchBend * 2), iPitchBendTime, iBaseFreq, idur - iPitchBendTime, iBaseFreq * 0.95
+
+  ; Generate square wave pulse for tonal component
+  aPulse vco2 0.5, kPitchEnv, 2, 0.5
+
+  ; Tonal envelope
+  kToneEnv expseg 1, iTonalDecayTime, 0.001, idur - iTonalDecayTime, 0.001
+  aTonal = aPulse * kToneEnv
+
+  ; Apply drum tone resonant filter
+  aDrumTone rezzy aTonal, kPitchEnv, iToneResonance
+
+  ; Generate white noise
+  aNoise noise 1, 0
+
+  ; Pulse modulation of noise (creates rhythmic texture)
+  kPulseMod oscili 1, iPulseRate
+  kPulseMod = (kPulseMod + 1) * 0.5
+  aNoiseModulated = aNoise * kPulseMod
+
+  ; Noise envelope
+  kNoiseEnv expseg 1, iNoiseDecayTime, 0.001, idur - iNoiseDecayTime, 0.001
+
+  ; Parallel filters on noise
+  ; Bandpass filter 1 (body)
+  aNoiseBody butterbp aNoiseModulated, iBaseFreq * 1.5, 100
+  ; Bandpass filter 2 (mid)
+  aNoiseMid butterbp aNoiseModulated, iBaseFreq * 3, 200
+  ; Highpass filter (crispness)
+  aNoiseHigh butterhp aNoiseModulated, 3000
+
+  ; Mix noise components
+  aNoiseMix = (aNoiseBody * 0.4 + aNoiseMid * 0.3 + aNoiseHigh * 0.3 * iBrightness) * kNoiseEnv
+
+  ; Mix tonal and noise
+  aMix = aDrumTone * 0.5 + aNoiseMix * 0.5
+
+  ; Cross-feedback delay network (simulates spring/snare wires)
+  ; Create two delay lines that feed back into each other
+  aDelay1Init init 0
+  aDelay2Init init 0
+
+  ; Spring tone filter (for the delayed signal)
+  iSpringFreq = 800 + iSpringTone * 4000
+
+  ; Delay line 1
+  aDelayIn1 = aMix + aDelay2Init * iFeedbackAmount * iCrossFeedMix
+  aDelay1 vdelay aDelayIn1, iDelayTime * 1000, 50
+  aDelay1Filt butterbp aDelay1, iSpringFreq, 100
+  aDelay1Out = aDelay1Filt * exp(-p3 / iSpringDecayTime)
+
+  ; Delay line 2
+  aDelayIn2 = aMix + aDelay1Out * iFeedbackAmount
+  aDelay2 vdelay aDelayIn2, iDelayTime * 1.3 * 1000, 50
+  aDelay2Filt butterbp aDelay2, iSpringFreq * 1.2, 120
+  aDelay2Out = aDelay2Filt * exp(-p3 / iSpringDecayTime)
+
+  ; Update feedback
+  aDelay1Init = aDelay1Out
+  aDelay2Init = aDelay2Out
+
+  ; Mix dry and delay
+  aOut = aMix * 0.6 + aDelay1Out * 0.2 + aDelay2Out * 0.2
+
+  ; Add snap transient
+  if iSnap > 0.1 then
+    kSnapEnv linseg 1, 0.003, 0, idur - 0.003, 0
+    aSnap noise iSnap * 0.5, 0
+    aSnapFilt butterhp aSnap, 8000
+    aOut = aOut + aSnapFilt * kSnapEnv
+  endif
+
+  ; Final output scaling
+  aOut = aOut * 0.4
+
+  ; Right channel with slightly different parameters
+  aPulseR vco2 0.5, kPitchEnv * 1.002, 2, 0.5
+  aTonalR = aPulseR * kToneEnv
+  aDrumToneR rezzy aTonalR, kPitchEnv * 1.002, iToneResonance
+
+  aNoiseR noise 1, 0
+  aNoiseModulatedR = aNoiseR * kPulseMod
+  aNoiseBodyR butterbp aNoiseModulatedR, iBaseFreq * 1.52, 100
+  aNoiseMidR butterbp aNoiseModulatedR, iBaseFreq * 3.03, 200
+  aNoiseHighR butterhp aNoiseModulatedR, 3100
+
+  aNoiseMixR = (aNoiseBodyR * 0.4 + aNoiseMidR * 0.3 + aNoiseHighR * 0.3 * iBrightness) * kNoiseEnv
+  aMixR = aDrumToneR * 0.5 + aNoiseMixR * 0.5
+
+  aDelay1InitR init 0
+  aDelay2InitR init 0
+
+  aDelayIn1R = aMixR + aDelay2InitR * iFeedbackAmount * iCrossFeedMix
+  aDelay1R vdelay aDelayIn1R, iDelayTime * 1.05 * 1000, 50
+  aDelay1FiltR butterbp aDelay1R, iSpringFreq * 1.01, 100
+  aDelay1OutR = aDelay1FiltR * exp(-p3 / iSpringDecayTime)
+
+  aDelayIn2R = aMixR + aDelay1OutR * iFeedbackAmount
+  aDelay2R vdelay aDelayIn2R, iDelayTime * 1.35 * 1000, 50
+  aDelay2FiltR butterbp aDelay2R, iSpringFreq * 1.22, 120
+  aDelay2OutR = aDelay2FiltR * exp(-p3 / iSpringDecayTime)
+
+  aDelay1InitR = aDelay1OutR
+  aDelay2InitR = aDelay2OutR
+
+  aOutR = aMixR * 0.6 + aDelay1OutR * 0.2 + aDelay2OutR * 0.2
+
+  if iSnap > 0.1 then
+    aSnapR noise iSnap * 0.5, 0
+    aSnapFiltR butterhp aSnapR, 8100
+    aOutR = aOutR + aSnapFiltR * kSnapEnv
+  endif
+
+  aOutR = aOutR * 0.4
+
+  outs aOut, aOutR
+endin
+`;
+  }
+
+  protected getParametersForCsound(params: FeedbackSnareParams): CsoundParameter[] {
+    return [
+      { channelName: 'baseFreq', value: params.baseFreq },
+      { channelName: 'tonalDecay', value: params.tonalDecay },
+      { channelName: 'noiseDecay', value: params.noiseDecay },
+      { channelName: 'toneResonance', value: params.toneResonance },
+      { channelName: 'springDecay', value: params.springDecay },
+      { channelName: 'springTone', value: params.springTone },
+      { channelName: 'pitchBend', value: params.pitchBend },
+      { channelName: 'pitchBendSpeed', value: params.pitchBendSpeed },
+      { channelName: 'pulseRate', value: params.pulseRate },
+      { channelName: 'feedbackAmount', value: params.feedbackAmount },
+      { channelName: 'delayTime', value: params.delayTime },
+      { channelName: 'crossFeedMix', value: params.crossFeedMix },
+      { channelName: 'snap', value: params.snap },
+      { channelName: 'brightness', value: params.brightness },
+    ];
+  }
+
+  randomParams(pitchLock?: PitchLock): FeedbackSnareParams {
+    const baseFreq = pitchLock?.enabled ? pitchLock.frequency : this.randomRange(150, 350);
+
+    return {
+      baseFreq,
+      tonalDecay: this.randomRange(0.1, 0.3),
+      noiseDecay: this.randomRange(0.3, 0.7),
+      toneResonance: this.randomRange(5, 25),
+      springDecay: this.randomRange(0.2, 0.6),
+      springTone: this.randomRange(0.2, 0.8),
+      pitchBend: this.randomRange(0.3, 0.9),
+      pitchBendSpeed: this.randomRange(0.01, 0.05),
+      pulseRate: this.randomRange(50, 300),
+      feedbackAmount: this.randomRange(0.3, 0.7),
+      delayTime: this.randomRange(0.005, 0.025),
+      crossFeedMix: this.randomRange(0.4, 0.9),
+      snap: this.randomRange(0, 0.6),
+      brightness: this.randomRange(0.3, 0.9),
+    };
+  }
+
+  mutateParams(
+    params: FeedbackSnareParams,
+    mutationAmount: number = 0.15,
+    pitchLock?: PitchLock
+  ): FeedbackSnareParams {
+    const baseFreq = pitchLock?.enabled ? pitchLock.frequency : params.baseFreq;
+
+    return {
+      baseFreq,
+      tonalDecay: this.mutateValue(params.tonalDecay, mutationAmount, 0.05, 0.5),
+      noiseDecay: this.mutateValue(params.noiseDecay, mutationAmount, 0.2, 0.9),
+      toneResonance: this.mutateValue(params.toneResonance, mutationAmount, 2, 40),
+      springDecay: this.mutateValue(params.springDecay, mutationAmount, 0.1, 0.8),
+      springTone: this.mutateValue(params.springTone, mutationAmount, 0, 1),
+      pitchBend: this.mutateValue(params.pitchBend, mutationAmount, 0.1, 1.2),
+      pitchBendSpeed: this.mutateValue(params.pitchBendSpeed, mutationAmount, 0.005, 0.1),
+      pulseRate: this.mutateValue(params.pulseRate, mutationAmount, 20, 500),
+      feedbackAmount: this.mutateValue(params.feedbackAmount, mutationAmount, 0.1, 0.85),
+      delayTime: this.mutateValue(params.delayTime, mutationAmount, 0.003, 0.04),
+      crossFeedMix: this.mutateValue(params.crossFeedMix, mutationAmount, 0.2, 1),
+      snap: this.mutateValue(params.snap, mutationAmount, 0, 0.8),
+      brightness: this.mutateValue(params.brightness, mutationAmount, 0, 1),
+    };
+  }
+}
diff --git a/src/lib/audio/engines/FormantFM.ts b/src/lib/audio/engines/FormantFM.ts
index bae0901..a89d1e3 100644
--- a/src/lib/audio/engines/FormantFM.ts
+++ b/src/lib/audio/engines/FormantFM.ts
@@ -61,6 +61,10 @@ export class FormantFM extends CsoundEngine<FormantFMParams> {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'FM' as const;
+  }
+
   protected getOrchestra(): string {
     return `
 instr 1
diff --git a/src/lib/audio/engines/FormantPopDrum.ts b/src/lib/audio/engines/FormantPopDrum.ts
new file mode 100644
index 0000000..3b60f2e
--- /dev/null
+++ b/src/lib/audio/engines/FormantPopDrum.ts
@@ -0,0 +1,142 @@
+import { CsoundEngine, type CsoundParameter } from './base/CsoundEngine';
+import type { PitchLock } from './base/SynthEngine';
+
+interface FormantPopDrumParams {
+  formant1Freq: number;
+  formant1Width: number;
+  formant2Freq: number;
+  formant2Width: number;
+  noiseDecay: number;
+  ampAttack: number;
+  ampDecay: number;
+  brightness: number;
+  stereoSpread: number;
+}
+
+export class FormantPopDrum extends CsoundEngine<FormantPopDrumParams> {
+  getName(): string {
+    return 'Formant Pop Drum';
+  }
+
+  getDescription(): string {
+    return 'Short noise burst through dual bandpass filters creating marimba-like or wooden drum tones';
+  }
+
+  getType() {
+    return 'generative' as const;
+  }
+
+  getCategory() {
+    return 'Percussion' as const;
+  }
+
+  protected getOrchestra(): string {
+    return `
+instr 1
+  iF1Freq chnget "formant1Freq"
+  iF1Width chnget "formant1Width"
+  iF2Freq chnget "formant2Freq"
+  iF2Width chnget "formant2Width"
+  iNoiseDecay chnget "noiseDecay"
+  iAmpAttack chnget "ampAttack"
+  iAmpDecay chnget "ampDecay"
+  iBrightness chnget "brightness"
+  iStereoSpread chnget "stereoSpread"
+
+  idur = p3
+  iNoiseDecayTime = iNoiseDecay * idur
+  iAmpAttackTime = iAmpAttack * idur
+  iAmpDecayTime = iAmpDecay * idur
+
+  ; Declick envelope for noise (very short to avoid clicks)
+  kDeclickEnv linseg 0, 0.001, 1, iNoiseDecayTime, 0, idur - iNoiseDecayTime - 0.001, 0
+
+  ; Generate random noise
+  aNoise noise 1, 0
+
+  ; Apply declick envelope to noise
+  aNoiseEnv = aNoise * kDeclickEnv
+
+  ; First bandpass filter (formant 1)
+  aFormant1 butterbp aNoiseEnv, iF1Freq, iF1Width
+
+  ; Second bandpass filter (formant 2)
+  aFormant2 butterbp aNoiseEnv, iF2Freq, iF2Width
+
+  ; Mix formants with brightness control
+  aMix = aFormant1 * (1 - iBrightness * 0.5) + aFormant2 * iBrightness
+
+  ; Amplitude envelope (exponential decay)
+  kAmpEnv expseg 0.001, iAmpAttackTime, 1, iAmpDecayTime, 0.001, idur - iAmpAttackTime - iAmpDecayTime, 0.001
+
+  ; Apply amplitude envelope
+  aOut = aMix * kAmpEnv
+
+  ; Stereo output with slight frequency offset for right channel
+  iF1FreqR = iF1Freq * (1 + iStereoSpread * 0.02)
+  iF2FreqR = iF2Freq * (1 + iStereoSpread * 0.02)
+
+  aFormant1R butterbp aNoiseEnv, iF1FreqR, iF1Width
+  aFormant2R butterbp aNoiseEnv, iF2FreqR, iF2Width
+
+  aMixR = aFormant1R * (1 - iBrightness * 0.5) + aFormant2R * iBrightness
+  aOutR = aMixR * kAmpEnv
+
+  outs aOut, aOutR
+endin
+`;
+  }
+
+  protected getParametersForCsound(params: FormantPopDrumParams): CsoundParameter[] {
+    return [
+      { channelName: 'formant1Freq', value: params.formant1Freq },
+      { channelName: 'formant1Width', value: params.formant1Width },
+      { channelName: 'formant2Freq', value: params.formant2Freq },
+      { channelName: 'formant2Width', value: params.formant2Width },
+      { channelName: 'noiseDecay', value: params.noiseDecay },
+      { channelName: 'ampAttack', value: params.ampAttack },
+      { channelName: 'ampDecay', value: params.ampDecay },
+      { channelName: 'brightness', value: params.brightness },
+      { channelName: 'stereoSpread', value: params.stereoSpread },
+    ];
+  }
+
+  randomParams(pitchLock?: PitchLock): FormantPopDrumParams {
+    const formant1FreqChoices = [200, 250, 300, 400, 500, 600, 800, 1000];
+    const formant1Freq = pitchLock?.enabled
+      ? pitchLock.frequency
+      : this.randomChoice(formant1FreqChoices) * this.randomRange(0.9, 1.1);
+
+    return {
+      formant1Freq,
+      formant1Width: this.randomRange(30, 120),
+      formant2Freq: formant1Freq * this.randomRange(1.5, 3.5),
+      formant2Width: this.randomRange(40, 150),
+      noiseDecay: this.randomRange(0.05, 0.3),
+      ampAttack: this.randomRange(0.001, 0.02),
+      ampDecay: this.randomRange(0.1, 0.6),
+      brightness: this.randomRange(0.2, 0.8),
+      stereoSpread: this.randomRange(0, 0.5),
+    };
+  }
+
+  mutateParams(
+    params: FormantPopDrumParams,
+    mutationAmount: number = 0.15,
+    pitchLock?: PitchLock
+  ): FormantPopDrumParams {
+    const formant1Freq = pitchLock?.enabled ? pitchLock.frequency : params.formant1Freq;
+
+    return {
+      formant1Freq,
+      formant1Width: this.mutateValue(params.formant1Width, mutationAmount, 20, 200),
+      formant2Freq: this.mutateValue(params.formant2Freq, mutationAmount, 300, 4000),
+      formant2Width: this.mutateValue(params.formant2Width, mutationAmount, 30, 250),
+      noiseDecay: this.mutateValue(params.noiseDecay, mutationAmount, 0.02, 0.5),
+      ampAttack: this.mutateValue(params.ampAttack, mutationAmount, 0.001, 0.05),
+      ampDecay: this.mutateValue(params.ampDecay, mutationAmount, 0.05, 0.8),
+      brightness: this.mutateValue(params.brightness, mutationAmount, 0, 1),
+      stereoSpread: this.mutateValue(params.stereoSpread, mutationAmount, 0, 1),
+    };
+  }
+}
diff --git a/src/lib/audio/engines/FourOpFM.ts b/src/lib/audio/engines/FourOpFM.ts
index 865099e..e52894d 100644
--- a/src/lib/audio/engines/FourOpFM.ts
+++ b/src/lib/audio/engines/FourOpFM.ts
@@ -75,6 +75,10 @@ export class FourOpFM implements SynthEngine<FourOpFMParams> {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'FM' as const;
+  }
+
   generate(params: FourOpFMParams, sampleRate: number, duration: number): [Float32Array, Float32Array] {
     const numSamples = Math.floor(sampleRate * duration);
     const leftBuffer = new Float32Array(numSamples);
diff --git a/src/lib/audio/engines/HiHat.ts b/src/lib/audio/engines/HiHat.ts
index 54808b4..c49c470 100644
--- a/src/lib/audio/engines/HiHat.ts
+++ b/src/lib/audio/engines/HiHat.ts
@@ -19,7 +19,7 @@ interface HiHatParams {
 
 export class HiHat implements SynthEngine {
   getName(): string {
-    return 'Hi-Hat';
+    return 'Noise Hi-Hat';
   }
 
   getDescription(): string {
@@ -30,6 +30,10 @@ export class HiHat implements SynthEngine {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Percussion' as const;
+  }
+
   randomParams(pitchLock?: PitchLock): HiHatParams {
     return {
       decay: Math.random(),
diff --git a/src/lib/audio/engines/Input.ts b/src/lib/audio/engines/Input.ts
index 9f179d9..3b97dfa 100644
--- a/src/lib/audio/engines/Input.ts
+++ b/src/lib/audio/engines/Input.ts
@@ -21,6 +21,10 @@ export class Input implements SynthEngine<InputParams> {
     return 'input' as const;
   }
 
+  getCategory() {
+    return 'Utility' as const;
+  }
+
   async record(duration: number): Promise<void> {
     const stream = await navigator.mediaDevices.getUserMedia({
       audio: {
diff --git a/src/lib/audio/engines/KarplusStrong.ts b/src/lib/audio/engines/KarplusStrong.ts
index d461213..b8aed2c 100644
--- a/src/lib/audio/engines/KarplusStrong.ts
+++ b/src/lib/audio/engines/KarplusStrong.ts
@@ -39,6 +39,10 @@ export class KarplusStrong implements SynthEngine<KarplusStrongParams> {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Physical' as const;
+  }
+
   generate(params: KarplusStrongParams, sampleRate: number, duration: number): [Float32Array, Float32Array] {
     const numSamples = Math.floor(sampleRate * duration);
     const leftBuffer = new Float32Array(numSamples);
diff --git a/src/lib/audio/engines/MassiveAdditive.ts b/src/lib/audio/engines/MassiveAdditive.ts
index 0e0acb3..6f925e1 100644
--- a/src/lib/audio/engines/MassiveAdditive.ts
+++ b/src/lib/audio/engines/MassiveAdditive.ts
@@ -39,6 +39,10 @@ export class MassiveAdditive extends CsoundEngine<MassiveAdditiveParams> {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Additive' as const;
+  }
+
   protected getOrchestra(): string {
     return `
 ; Function tables for sine wave
diff --git a/src/lib/audio/engines/NoiseDrum.ts b/src/lib/audio/engines/NoiseDrum.ts
index 06c71b9..e97fd6a 100644
--- a/src/lib/audio/engines/NoiseDrum.ts
+++ b/src/lib/audio/engines/NoiseDrum.ts
@@ -39,7 +39,7 @@ interface NoiseDrumParams {
 
 export class NoiseDrum implements SynthEngine {
   getName(): string {
-    return 'NPerc';
+    return 'Noise Perc';
   }
 
   getDescription(): string {
@@ -50,6 +50,10 @@ export class NoiseDrum implements SynthEngine {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Percussion' as const;
+  }
+
   randomParams(): NoiseDrumParams {
     // Intelligent parameter generation based on correlated characteristics
 
@@ -93,16 +97,16 @@ export class NoiseDrum implements SynthEngine {
     const filterType = filterFreq < 0.3 ?
       Math.random() * 0.35 : // Low freq prefers lowpass
       filterFreq > 0.7 ?
-      0.5 + Math.random() * 0.5 : // High freq prefers highpass/bandpass
-      Math.random(); // Mid freq - any type
+        0.5 + Math.random() * 0.5 : // High freq prefers highpass/bandpass
+        Math.random(); // Mid freq - any type
 
     // Decay time inversely correlates with frequency
     const decayBias = Math.random();
     const ampDecay = filterFreq < 0.3 ?
       0.25 + decayBias * 0.4 : // Low freq can be longer
       filterFreq > 0.6 ?
-      0.08 + decayBias * 0.35 : // High freq shorter
-      0.2 + decayBias * 0.45; // Mid range
+        0.08 + decayBias * 0.35 : // High freq shorter
+        0.2 + decayBias * 0.45; // Mid range
 
     // Attack is generally very short for percussion
     const ampAttack = Math.random() < 0.85 ?
@@ -372,7 +376,7 @@ export class NoiseDrum implements SynthEngine {
 
           // Blend body resonance - SUBTLE
           sample = sample * (1 - params.bodyAmount * 0.4) +
-                   bodyFiltered.output * params.bodyAmount * 0.6 * bodyEnv;
+            bodyFiltered.output * params.bodyAmount * 0.6 * bodyEnv;
         }
 
         // Apply amplitude envelope
@@ -434,7 +438,7 @@ export class NoiseDrum implements SynthEngine {
       pinkState[5] = -0.7616 * pinkState[5] - whiteNoise * 0.0168980;
 
       const pink = pinkState[0] + pinkState[1] + pinkState[2] + pinkState[3] +
-                   pinkState[4] + pinkState[5] + pinkState[6] + whiteNoise * 0.5362;
+        pinkState[4] + pinkState[5] + pinkState[6] + whiteNoise * 0.5362;
       pinkState[6] = whiteNoise * 0.115926;
 
       return pink * 0.11;
diff --git a/src/lib/audio/engines/ParticleNoise.ts b/src/lib/audio/engines/ParticleNoise.ts
index 1c2894c..e6be5d0 100644
--- a/src/lib/audio/engines/ParticleNoise.ts
+++ b/src/lib/audio/engines/ParticleNoise.ts
@@ -38,6 +38,10 @@ export class ParticleNoise implements SynthEngine {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Noise' as const;
+  }
+
   randomParams(pitchLock?: PitchLock): ParticleNoiseParams {
     const densityBias = Math.random();
 
diff --git a/src/lib/audio/engines/PhaseDistortionFM.ts b/src/lib/audio/engines/PhaseDistortionFM.ts
index 786c80e..1200482 100644
--- a/src/lib/audio/engines/PhaseDistortionFM.ts
+++ b/src/lib/audio/engines/PhaseDistortionFM.ts
@@ -65,7 +65,7 @@ export class PhaseDistortionFM implements SynthEngine<PhaseDistortionFMParams> {
   private static workletURL: string | null = null;
 
   getName(): string {
-    return 'PD';
+    return 'Phase Dist';
   }
 
   getDescription(): string {
@@ -76,6 +76,10 @@ export class PhaseDistortionFM implements SynthEngine<PhaseDistortionFMParams> {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'FM' as const;
+  }
+
   generate(params: PhaseDistortionFMParams, sampleRate: number, duration: number): [Float32Array, Float32Array] {
     const numSamples = Math.floor(sampleRate * duration);
     const leftBuffer = new Float32Array(numSamples);
diff --git a/src/lib/audio/engines/Ring.ts b/src/lib/audio/engines/Ring.ts
index 236b79b..00c3a29 100644
--- a/src/lib/audio/engines/Ring.ts
+++ b/src/lib/audio/engines/Ring.ts
@@ -82,6 +82,10 @@ export class Ring implements SynthEngine<RingParams> {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Modulation' as const;
+  }
+
   generate(params: RingParams, sampleRate: number, duration: number): [Float32Array, Float32Array] {
     const numSamples = Math.floor(sampleRate * duration);
     const leftBuffer = new Float32Array(numSamples);
diff --git a/src/lib/audio/engines/RingCymbal.ts b/src/lib/audio/engines/RingCymbal.ts
new file mode 100644
index 0000000..a4a1ddf
--- /dev/null
+++ b/src/lib/audio/engines/RingCymbal.ts
@@ -0,0 +1,178 @@
+import { CsoundEngine, type CsoundParameter } from './base/CsoundEngine';
+import type { PitchLock } from './base/SynthEngine';
+
+interface RingCymbalParams {
+  baseFreq: number;
+  overtone1Freq: number;
+  overtone2Freq: number;
+  overtone3Freq: number;
+  overtone1Vol: number;
+  overtone2Vol: number;
+  overtone3Vol: number;
+  filterCutoff: number;
+  resonance: number;
+  decay: number;
+  attack: number;
+  noise: number;
+  brightness: number;
+  spread: number;
+}
+
+export class RingCymbal extends CsoundEngine<RingCymbalParams> {
+  getName(): string {
+    return 'Ring Cymbal';
+  }
+
+  getDescription(): string {
+    return 'Metallic cymbal using ring modulation with noise and multiple oscillators';
+  }
+
+  getType() {
+    return 'generative' as const;
+  }
+
+  getCategory() {
+    return 'Percussion' as const;
+  }
+
+  protected getOrchestra(): string {
+    return `
+instr 1
+  iBaseFreq chnget "baseFreq"
+  iOvertone1Freq chnget "overtone1Freq"
+  iOvertone2Freq chnget "overtone2Freq"
+  iOvertone3Freq chnget "overtone3Freq"
+  iOvertone1Vol chnget "overtone1Vol"
+  iOvertone2Vol chnget "overtone2Vol"
+  iOvertone3Vol chnget "overtone3Vol"
+  iFilterCutoff chnget "filterCutoff"
+  iResonance chnget "resonance"
+  iDecay chnget "decay"
+  iAttack chnget "attack"
+  iNoise chnget "noise"
+  iBrightness chnget "brightness"
+  iSpread chnget "spread"
+
+  idur = p3
+  iDecayTime = iDecay * idur
+  iAttackTime = iAttack * idur
+
+  ; Exponential decay envelope with attack
+  kEnv linseg 0, iAttackTime, 1, iDecayTime - iAttackTime, 0.001, 0.001, 0
+  kEnv = kEnv * kEnv
+
+  ; Generate white noise source
+  aNoise noise 1, 0
+
+  ; Generate impulse oscillators at different frequencies
+  aOsc1 oscili 1, iBaseFreq
+  aOsc2 oscili iOvertone1Vol, iOvertone1Freq
+  aOsc3 oscili iOvertone2Vol, iOvertone2Freq
+  aOsc4 oscili iOvertone3Vol, iOvertone3Freq
+
+  ; Ring modulation: multiply noise with oscillators
+  aRing1 = aNoise * aOsc1
+  aRing2 = aNoise * aOsc2
+  aRing3 = aNoise * aOsc3
+  aRing4 = aNoise * aOsc4
+
+  ; Mix ring modulated signals
+  aMix = (aRing1 + aRing2 + aRing3 + aRing4) * 0.25
+
+  ; Add raw noise for character
+  aMix = aMix * (1 - iNoise) + aNoise * iNoise * 0.3
+
+  ; Apply resonant high-pass filter for metallic character
+  aFiltered butterhp aMix, iFilterCutoff, iResonance
+
+  ; Additional high-pass for brightness
+  if iBrightness > 0.3 then
+    aFiltered butterhp aFiltered, iFilterCutoff * (1 + iBrightness), iResonance * 0.5
+  endif
+
+  ; Apply envelope
+  aOut = aFiltered * kEnv * 0.4
+
+  ; Stereo spread using slightly different filter parameters
+  iFilterCutoffR = iFilterCutoff * (1 + iSpread * 0.1)
+  aFilteredR butterhp aMix, iFilterCutoffR, iResonance
+
+  if iBrightness > 0.3 then
+    aFilteredR butterhp aFilteredR, iFilterCutoffR * (1 + iBrightness), iResonance * 0.5
+  endif
+
+  aOutR = aFilteredR * kEnv * 0.4
+
+  outs aOut, aOutR
+endin
+`;
+  }
+
+  protected getParametersForCsound(params: RingCymbalParams): CsoundParameter[] {
+    return [
+      { channelName: 'baseFreq', value: params.baseFreq },
+      { channelName: 'overtone1Freq', value: params.overtone1Freq },
+      { channelName: 'overtone2Freq', value: params.overtone2Freq },
+      { channelName: 'overtone3Freq', value: params.overtone3Freq },
+      { channelName: 'overtone1Vol', value: params.overtone1Vol },
+      { channelName: 'overtone2Vol', value: params.overtone2Vol },
+      { channelName: 'overtone3Vol', value: params.overtone3Vol },
+      { channelName: 'filterCutoff', value: params.filterCutoff },
+      { channelName: 'resonance', value: params.resonance },
+      { channelName: 'decay', value: params.decay },
+      { channelName: 'attack', value: params.attack },
+      { channelName: 'noise', value: params.noise },
+      { channelName: 'brightness', value: params.brightness },
+      { channelName: 'spread', value: params.spread },
+    ];
+  }
+
+  randomParams(pitchLock?: PitchLock): RingCymbalParams {
+    const baseFreq = pitchLock?.enabled ? pitchLock.frequency : this.randomRange(800, 1800);
+
+    const inharmonicRatios = [1.4, 1.7, 2.1, 2.3, 2.9, 3.1, 3.7, 4.3];
+
+    return {
+      baseFreq,
+      overtone1Freq: baseFreq * this.randomChoice(inharmonicRatios),
+      overtone2Freq: baseFreq * this.randomChoice(inharmonicRatios),
+      overtone3Freq: baseFreq * this.randomChoice(inharmonicRatios),
+      overtone1Vol: this.randomRange(0.4, 1.0),
+      overtone2Vol: this.randomRange(0.3, 0.9),
+      overtone3Vol: this.randomRange(0.2, 0.7),
+      filterCutoff: this.randomRange(3000, 8000),
+      resonance: this.randomRange(2, 8),
+      decay: this.randomRange(0.3, 0.9),
+      attack: this.randomRange(0.001, 0.02),
+      noise: this.randomRange(0.1, 0.5),
+      brightness: this.randomRange(0, 0.8),
+      spread: this.randomRange(0.01, 0.15),
+    };
+  }
+
+  mutateParams(
+    params: RingCymbalParams,
+    mutationAmount: number = 0.15,
+    pitchLock?: PitchLock
+  ): RingCymbalParams {
+    const baseFreq = pitchLock?.enabled ? pitchLock.frequency : params.baseFreq;
+    const freqRatio = baseFreq / params.baseFreq;
+
+    return {
+      baseFreq,
+      overtone1Freq: this.mutateValue(params.overtone1Freq * freqRatio, mutationAmount, baseFreq * 1.2, baseFreq * 5),
+      overtone2Freq: this.mutateValue(params.overtone2Freq * freqRatio, mutationAmount, baseFreq * 1.2, baseFreq * 5),
+      overtone3Freq: this.mutateValue(params.overtone3Freq * freqRatio, mutationAmount, baseFreq * 1.2, baseFreq * 5),
+      overtone1Vol: this.mutateValue(params.overtone1Vol, mutationAmount, 0.2, 1.0),
+      overtone2Vol: this.mutateValue(params.overtone2Vol, mutationAmount, 0.1, 1.0),
+      overtone3Vol: this.mutateValue(params.overtone3Vol, mutationAmount, 0.1, 0.9),
+      filterCutoff: this.mutateValue(params.filterCutoff, mutationAmount, 2000, 10000),
+      resonance: this.mutateValue(params.resonance, mutationAmount, 1, 12),
+      decay: this.mutateValue(params.decay, mutationAmount, 0.2, 1.0),
+      attack: this.mutateValue(params.attack, mutationAmount, 0.001, 0.05),
+      noise: this.mutateValue(params.noise, mutationAmount, 0, 0.7),
+      brightness: this.mutateValue(params.brightness, mutationAmount, 0, 1),
+      spread: this.mutateValue(params.spread, mutationAmount, 0.005, 0.25),
+    };
+  }
+}
diff --git a/src/lib/audio/engines/Sample.ts b/src/lib/audio/engines/Sample.ts
index 13160eb..a6ee8ac 100644
--- a/src/lib/audio/engines/Sample.ts
+++ b/src/lib/audio/engines/Sample.ts
@@ -21,6 +21,10 @@ export class Sample implements SynthEngine<SampleParams> {
     return 'sample' as const;
   }
 
+  getCategory() {
+    return 'Utility' as const;
+  }
+
   async loadFile(file: File): Promise<void> {
     const arrayBuffer = await file.arrayBuffer();
     const audioContext = new AudioContext();
diff --git a/src/lib/audio/engines/Snare.ts b/src/lib/audio/engines/Snare.ts
index 6a98995..c33457a 100644
--- a/src/lib/audio/engines/Snare.ts
+++ b/src/lib/audio/engines/Snare.ts
@@ -23,7 +23,7 @@ interface SnareParams {
 
 export class Snare implements SynthEngine {
   getName(): string {
-    return 'Snare';
+    return 'Noise Snare';
   }
 
   getDescription(): string {
@@ -34,6 +34,10 @@ export class Snare implements SynthEngine {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Percussion' as const;
+  }
+
   randomParams(pitchLock?: PitchLock): SnareParams {
     return {
       baseFreq: pitchLock ? this.freqToParam(pitchLock.frequency) : 0.3 + Math.random() * 0.4,
diff --git a/src/lib/audio/engines/SubtractiveThreeOsc.ts b/src/lib/audio/engines/SubtractiveThreeOsc.ts
index 6db291c..772c86b 100644
--- a/src/lib/audio/engines/SubtractiveThreeOsc.ts
+++ b/src/lib/audio/engines/SubtractiveThreeOsc.ts
@@ -50,6 +50,10 @@ export class SubtractiveThreeOsc extends CsoundEngine<SubtractiveThreeOscParams>
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Subtractive' as const;
+  }
+
   protected getOrchestra(): string {
     return `
 instr 1
diff --git a/src/lib/audio/engines/TechnoKick.ts b/src/lib/audio/engines/TechnoKick.ts
new file mode 100644
index 0000000..a576820
--- /dev/null
+++ b/src/lib/audio/engines/TechnoKick.ts
@@ -0,0 +1,187 @@
+import { CsoundEngine, type CsoundParameter } from './base/CsoundEngine';
+import type { PitchLock } from './base/SynthEngine';
+
+interface TechnoKickParams {
+  startFreq: number;
+  endFreq: number;
+  freqDecay: number;
+  resonance: number;
+  cutoffStart: number;
+  cutoffEnd: number;
+  cutoffDecay: number;
+  ampAttack: number;
+  ampDecay: number;
+  noiseMix: number;
+  punch: number;
+  stereoWidth: number;
+}
+
+export class TechnoKick extends CsoundEngine<TechnoKickParams> {
+  getName(): string {
+    return 'Techno Kick';
+  }
+
+  getDescription(): string {
+    return 'Noise through resonant low-pass filter with frequency sweep and RMS compression for punchy electronic kicks';
+  }
+
+  getType() {
+    return 'generative' as const;
+  }
+
+  getCategory() {
+    return 'Percussion' as const;
+  }
+
+  protected getOrchestra(): string {
+    return `
+instr 1
+  iStartFreq chnget "startFreq"
+  iEndFreq chnget "endFreq"
+  iFreqDecay chnget "freqDecay"
+  iResonance chnget "resonance"
+  iCutoffStart chnget "cutoffStart"
+  iCutoffEnd chnget "cutoffEnd"
+  iCutoffDecay chnget "cutoffDecay"
+  iAmpAttack chnget "ampAttack"
+  iAmpDecay chnget "ampDecay"
+  iNoiseMix chnget "noiseMix"
+  iPunch chnget "punch"
+  iStereoWidth chnget "stereoWidth"
+
+  idur = p3
+  iFreqDecayTime = iFreqDecay * idur
+  iCutoffDecayTime = iCutoffDecay * idur
+  iAmpAttackTime = iAmpAttack * idur
+  iAmpDecayTime = iAmpDecay * idur
+
+  ; Generate random noise
+  aNoise noise 1, 0
+
+  ; Frequency envelope for the filter cutoff (exponential sweep)
+  kFreqEnv expseg iStartFreq, iFreqDecayTime, iEndFreq, idur - iFreqDecayTime, iEndFreq
+
+  ; Cutoff modulation envelope
+  kCutoffEnv expseg iCutoffStart, iCutoffDecayTime, iCutoffEnd, idur - iCutoffDecayTime, iCutoffEnd
+
+  ; Apply resonant low-pass filter (rezzy)
+  aFiltered rezzy aNoise * (1 + iNoiseMix), kCutoffEnv, iResonance
+
+  ; Add sine sub-bass component for more weight
+  kSubFreqEnv expseg iStartFreq * 0.5, iFreqDecayTime, iEndFreq * 0.5, idur - iFreqDecayTime, iEndFreq * 0.5
+  aSubBass oscili 0.6, kSubFreqEnv
+
+  ; Mix filtered noise and sub-bass
+  aMix = aFiltered * 0.5 + aSubBass
+
+  ; Amplitude envelope (exponential)
+  kAmpEnv expseg 0.001, iAmpAttackTime, 1, iAmpDecayTime, 0.001, idur - iAmpAttackTime - iAmpDecayTime, 0.001
+
+  ; Apply amplitude envelope
+  aEnveloped = aMix * kAmpEnv
+
+  ; RMS compression for punch
+  ; Calculate RMS of signal
+  kRMS rms aEnveloped
+  if kRMS < 0.01 then
+    kCompGain = 1
+  else
+    kCompGain = 1 + iPunch * (0.3 / kRMS - 1)
+  endif
+  kCompGain limit kCompGain, 0.5, 3
+
+  aOut = aEnveloped * kCompGain
+
+  ; Right channel with stereo width
+  iStartFreqR = iStartFreq * (1 + iStereoWidth * 0.01)
+  iEndFreqR = iEndFreq * (1 + iStereoWidth * 0.01)
+
+  kFreqEnvR expseg iStartFreqR, iFreqDecayTime, iEndFreqR, idur - iFreqDecayTime, iEndFreqR
+  kCutoffEnvR expseg iCutoffStart * (1 + iStereoWidth * 0.02), iCutoffDecayTime, iCutoffEnd * (1 + iStereoWidth * 0.02), idur - iCutoffDecayTime, iCutoffEnd * (1 + iStereoWidth * 0.02)
+
+  aNoiseR noise 1, 0
+  aFilteredR rezzy aNoiseR * (1 + iNoiseMix), kCutoffEnvR, iResonance
+
+  kSubFreqEnvR expseg iStartFreqR * 0.5, iFreqDecayTime, iEndFreqR * 0.5, idur - iFreqDecayTime, iEndFreqR * 0.5
+  aSubBassR oscili 0.6, kSubFreqEnvR
+
+  aMixR = aFilteredR * 0.5 + aSubBassR
+  aEnvelopedR = aMixR * kAmpEnv
+
+  kRMSR rms aEnvelopedR
+  if kRMSR < 0.01 then
+    kCompGainR = 1
+  else
+    kCompGainR = 1 + iPunch * (0.3 / kRMSR - 1)
+  endif
+  kCompGainR limit kCompGainR, 0.5, 3
+
+  aOutR = aEnvelopedR * kCompGainR
+
+  outs aOut, aOutR
+endin
+`;
+  }
+
+  protected getParametersForCsound(params: TechnoKickParams): CsoundParameter[] {
+    return [
+      { channelName: 'startFreq', value: params.startFreq },
+      { channelName: 'endFreq', value: params.endFreq },
+      { channelName: 'freqDecay', value: params.freqDecay },
+      { channelName: 'resonance', value: params.resonance },
+      { channelName: 'cutoffStart', value: params.cutoffStart },
+      { channelName: 'cutoffEnd', value: params.cutoffEnd },
+      { channelName: 'cutoffDecay', value: params.cutoffDecay },
+      { channelName: 'ampAttack', value: params.ampAttack },
+      { channelName: 'ampDecay', value: params.ampDecay },
+      { channelName: 'noiseMix', value: params.noiseMix },
+      { channelName: 'punch', value: params.punch },
+      { channelName: 'stereoWidth', value: params.stereoWidth },
+    ];
+  }
+
+  randomParams(pitchLock?: PitchLock): TechnoKickParams {
+    const endFreqChoices = [40, 45, 50, 55, 60, 70, 80];
+    const endFreq = pitchLock?.enabled
+      ? pitchLock.frequency
+      : this.randomChoice(endFreqChoices) * this.randomRange(0.95, 1.05);
+
+    return {
+      startFreq: this.randomRange(800, 1200),
+      endFreq,
+      freqDecay: this.randomRange(0.05, 0.25),
+      resonance: this.randomRange(5, 40),
+      cutoffStart: this.randomRange(300, 800),
+      cutoffEnd: this.randomRange(80, 200),
+      cutoffDecay: this.randomRange(0.1, 0.4),
+      ampAttack: this.randomRange(0.001, 0.005),
+      ampDecay: this.randomRange(0.2, 0.6),
+      noiseMix: this.randomRange(0.1, 0.8),
+      punch: this.randomRange(0.3, 0.9),
+      stereoWidth: this.randomRange(0, 0.3),
+    };
+  }
+
+  mutateParams(
+    params: TechnoKickParams,
+    mutationAmount: number = 0.15,
+    pitchLock?: PitchLock
+  ): TechnoKickParams {
+    const endFreq = pitchLock?.enabled ? pitchLock.frequency : params.endFreq;
+
+    return {
+      startFreq: this.mutateValue(params.startFreq, mutationAmount, 600, 1500),
+      endFreq,
+      freqDecay: this.mutateValue(params.freqDecay, mutationAmount, 0.02, 0.4),
+      resonance: this.mutateValue(params.resonance, mutationAmount, 3, 50),
+      cutoffStart: this.mutateValue(params.cutoffStart, mutationAmount, 200, 1000),
+      cutoffEnd: this.mutateValue(params.cutoffEnd, mutationAmount, 60, 300),
+      cutoffDecay: this.mutateValue(params.cutoffDecay, mutationAmount, 0.05, 0.6),
+      ampAttack: this.mutateValue(params.ampAttack, mutationAmount, 0.001, 0.01),
+      ampDecay: this.mutateValue(params.ampDecay, mutationAmount, 0.1, 0.8),
+      noiseMix: this.mutateValue(params.noiseMix, mutationAmount, 0, 1),
+      punch: this.mutateValue(params.punch, mutationAmount, 0.1, 1),
+      stereoWidth: this.mutateValue(params.stereoWidth, mutationAmount, 0, 0.5),
+    };
+  }
+}
diff --git a/src/lib/audio/engines/TwoOpFM.ts b/src/lib/audio/engines/TwoOpFM.ts
index f0a1aa6..9ed7891 100644
--- a/src/lib/audio/engines/TwoOpFM.ts
+++ b/src/lib/audio/engines/TwoOpFM.ts
@@ -73,6 +73,10 @@ export class TwoOpFM implements SynthEngine<TwoOpFMParams> {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'FM' as const;
+  }
+
   generate(params: TwoOpFMParams, sampleRate: number, duration: number): [Float32Array, Float32Array] {
     const numSamples = Math.floor(sampleRate * duration);
     const leftBuffer = new Float32Array(numSamples);
diff --git a/src/lib/audio/engines/ZzfxEngine.ts b/src/lib/audio/engines/ZzfxEngine.ts
index b1a3022..2ca5b0a 100644
--- a/src/lib/audio/engines/ZzfxEngine.ts
+++ b/src/lib/audio/engines/ZzfxEngine.ts
@@ -38,6 +38,10 @@ export class ZzfxEngine implements SynthEngine<ZzfxParams> {
     return 'generative' as const;
   }
 
+  getCategory() {
+    return 'Experimental' as const;
+  }
+
   generate(params: ZzfxParams, sampleRate: number, duration: number): [Float32Array, Float32Array] {
     // ZZFX uses 44100 sample rate internally
     const zzfxSampleRate = 44100;
diff --git a/src/lib/audio/engines/base/SynthEngine.ts b/src/lib/audio/engines/base/SynthEngine.ts
index 94c8e1b..76ceb5a 100644
--- a/src/lib/audio/engines/base/SynthEngine.ts
+++ b/src/lib/audio/engines/base/SynthEngine.ts
@@ -6,6 +6,17 @@
 
 export type EngineType = 'generative' | 'sample' | 'input';
 
+export type EngineCategory =
+  | 'Additive'
+  | 'Subtractive'
+  | 'FM'
+  | 'Percussion'
+  | 'Noise'
+  | 'Physical'
+  | 'Modulation'
+  | 'Experimental'
+  | 'Utility';
+
 export interface PitchLock {
   enabled: boolean;
   frequency: number; // Frequency in Hz
@@ -15,6 +26,7 @@ export interface SynthEngine<T = any> {
   getName(): string;
   getDescription(): string;
   getType(): EngineType;
+  getCategory(): EngineCategory;
   generate(params: T, sampleRate: number, duration: number, pitchLock?: PitchLock): [Float32Array, Float32Array] | Promise<[Float32Array, Float32Array]>;
   randomParams(pitchLock?: PitchLock): T;
   mutateParams(params: T, mutationAmount?: number, pitchLock?: PitchLock): T;
diff --git a/src/lib/audio/engines/registry.ts b/src/lib/audio/engines/registry.ts
index 6e97070..0bc39a0 100644
--- a/src/lib/audio/engines/registry.ts
+++ b/src/lib/audio/engines/registry.ts
@@ -19,6 +19,12 @@ import { ParticleNoise } from './ParticleNoise';
 import { DustNoise } from './DustNoise';
 import { SubtractiveThreeOsc } from './SubtractiveThreeOsc';
 import { MassiveAdditive } from './MassiveAdditive';
+import { FormantPopDrum } from './FormantPopDrum';
+import { TechnoKick } from './TechnoKick';
+import { FMTomTom } from './FMTomTom';
+import { RingCymbal } from './RingCymbal';
+import { AdditiveBass } from './AdditiveBass';
+import { FeedbackSnare } from './FeedbackSnare';
 
 export const engines: SynthEngine[] = [
   new Sample(),
@@ -34,6 +40,12 @@ export const engines: SynthEngine[] = [
   new Snare(),
   new BassDrum(),
   new HiHat(),
+  new FormantPopDrum(),
+  new TechnoKick(),
+  new FMTomTom(),
+  new RingCymbal(),
+  new AdditiveBass(),
+  new FeedbackSnare(),
   new Ring(),
   new KarplusStrong(),
   new AdditiveEngine(),
diff --git a/src/lib/utils/settings.ts b/src/lib/utils/settings.ts
index e53f60b..e162a4b 100644
--- a/src/lib/utils/settings.ts
+++ b/src/lib/utils/settings.ts
@@ -8,6 +8,7 @@ const STORAGE_KEYS = {
   DURATION: 'duration',
   PITCH_LOCK_ENABLED: 'pitchLockEnabled',
   PITCH_LOCK_FREQUENCY: 'pitchLockFrequency',
+  EXPANDED_CATEGORIES: 'expandedCategories',
 } as const;
 
 export function loadVolume(): number {
@@ -45,3 +46,20 @@ export function loadPitchLockFrequency(): number {
 export function savePitchLockFrequency(frequency: number): void {
   localStorage.setItem(STORAGE_KEYS.PITCH_LOCK_FREQUENCY, frequency.toString());
 }
+
+export function loadExpandedCategories(): Set<string> {
+  const stored = localStorage.getItem(STORAGE_KEYS.EXPANDED_CATEGORIES);
+  if (stored) {
+    try {
+      const parsed = JSON.parse(stored);
+      return new Set(Array.isArray(parsed) ? parsed : []);
+    } catch {
+      return new Set();
+    }
+  }
+  return new Set();
+}
+
+export function saveExpandedCategories(categories: Set<string>): void {
+  localStorage.setItem(STORAGE_KEYS.EXPANDED_CATEGORIES, JSON.stringify(Array.from(categories)));
+}