✂️ Sample Chopper Pro
MPC-style sampling for the browser — Works with any audio source: files, vinyl, or microphone
2
Workflow Modes
22
Pro Features
✅
All Phases Complete
+8
Bonus Features

📋 Executive Summary

The Sample Chopper Pro upgrade transforms FlowState's sample slicer into a professional-grade sampling workstation. It works for everyone — whether you're chopping samples from files you download, or recording directly from a turntable.

💡 Key Insight

Vinyl recording is an optional enhancement, not a requirement. All core features work with drag-and-drop files. We're adding hardware recording for users who want it — but the Chopper is powerful even without any external gear.

🎯 Two Workflow Paths

The Sample Chopper Pro supports two distinct workflows — choose what fits your setup:

📁
File-Based Workflow
Perfect for: Most producers

  • Downloaded samples from Splice, Looperman, etc.
  • Audio files from YouTube converters
  • Samples shared by collaborators
  • Any WAV/MP3/FLAC file on your computer
No hardware needed — just drag & drop
🎙️
Hardware Recording Workflow
Perfect for: Vinyl diggers, live samplers

  • USB turntables (Audio-Technica, Numark)
  • Audio interfaces (Scarlett, Apollo)
  • Cassette decks, CD players
  • Microphones for field recording
Requires USB audio device — Phase 1 feature
🔄 Both Workflows → Same Powerful Tools

Once audio is loaded (whether from file or recording), you get the same pro features: pitch shift, reverse, time-stretch, choke groups, BPM detection, groove templates, and WAV export. The source doesn't matter — the Chopper treats all audio equally.

📊 Feature Comparison

How FlowState Sample Chopper compares to professional tools:

Feature FlowState Serato Sample Maschine
Record from turntable ✅ ✅ ✅
Transient detection ✅ ✅ ✅
Grid divide ✅ ✅ ✅
Manual slicing ✅ ✅ ✅
Pitch shift per slice ✅ ✅ ✅
Reverse/half-speed ✅ ✅ ✅
Choke groups (A-D) ✅ ✅ ✅
Export individual WAVs ✅ ✅ ✅
Batch export as ZIP ✅ Bonus ❌ ✅
BPM detection ✅ ✅ ✅
Time-stretch slices ✅ ✅ ✅
Swing/groove templates ✅ ✅ ✅
Slice layering ✅ ❌ ✅
ADSR Envelope per slice ✅ Bonus ❌ ✅
Crossfade options ✅ Bonus ❌ ✅
Warp markers ✅ Bonus ❌ ✅
Bake FX to export ✅ Bonus ✅ ✅
Runs in browser ✅ ❌ ❌
AI Producer Assist ✅ Bonus ❌ ❌

🔬 Research Findings

A specialized research swarm analyzed five key areas before development:

🔌
Hardware Integration Specialist
Turntable → Browser connectivity
  • ✓ USB turntables and audio interfaces work with Web Audio via getUserMedia()
  • ✓ Device selection possible via enumerateDevices() API
  • ✓ RIAA equalization handled by hardware phono preamps (no software needed)
  • ✓ Ground hum mitigated with 80Hz high-pass filter option
  • ✓ Browser latency 30-50ms acceptable; hardware monitoring recommended
🌐
Web Audio 2025 Technology Researcher
Browser API assessment
  • ✓ Web Audio API remains the best choice — no replacement needed
  • ✓ AudioWorklet now universal (including Safari iOS 15+)
  • ✓ WebCodecs emerging but not ready for real-time recording
  • ✓ 44.1kHz and 48kHz universally supported; 96kHz hardware-dependent
  • ✓ Safari sampleRate bug exists — use ideal not exact constraint
🎨
UX Design Specialist
Audio input selection workflow
  • ✓ Hybrid approach: Global default + per-track override
  • ✓ Zero-click workflow for repeat sessions (remembers USB Turntable)
  • ✓ Auto-detection toast when new audio devices connect
  • ✓ Peak + RMS meters with -6dBFS target line
  • ✓ Vinyl sampling flow: Arm → Record → Stop → Chop (4-5 clicks)
🔗
Integration Architect
Recording → Chopper flow
  • ✓ Recommended: "Send to Chopper" toast (scored 26/30 vs alternatives)
  • ✓ Record button directly in Chopper (bypass timeline option)
  • ✓ Add initialAudioUrl prop to SampleChopper component
  • ✓ Handle long recordings with duration warning (>3 min)
  • ✓ Future: Context menu on timeline clips → "Send to Chopper"
🎚️
Audio Engineer Specialist
Vinyl recording quality specs
  • ✓ 48kHz / 24-bit recommended (96kHz for archival)
  • ✓ Disable all processing: echoCancellation, noiseSuppression, autoGainControl = false
  • ✓ Target peak: -6dBFS (6dB headroom for transients)
  • ✓ WAV codec for recording (not Opus) — preserve vinyl character
  • ✓ Optional 20Hz high-pass for subsonic rumble removal

🎚️ Audio Quality Specifications

Voice Mode (Current)

Sample Rate16kHz
ChannelsMono
CodecWebM Opus
echoCancellationtrue
noiseSuppressiontrue
autoGainControltrue

Vinyl Mode (New)

Sample Rate48kHz (96kHz optional)
Bit Depth24-bit
ChannelsStereo
CodecWAV PCM (uncompressed)
echoCancellationfalse ✓
noiseSuppressionfalse ✓ (preserve crackle)
autoGainControlfalse ✓ (preserve dynamics)
Target Peak-6dBFS
Rumble Filter20Hz high-pass (optional)

🚀 Implementation Status

✅ Phase 1: Record Into Chopper
COMPLETE

Vinyl sampling fully implemented

  • ✓ Record button directly in Chopper UI — ChopperRecorder.tsx
  • ✓ Device selector dropdown — DeviceSelector.tsx
  • ✓ Vinyl Mode preset (disable all processing)
  • ✓ Live input level meters — InputMeter.tsx
  • ✓ Auto-load into waveform when recording stops
✅ Phase 2: Slice Manipulation
COMPLETE

MPC-style control implemented

  • ✓ Pitch shift per slice (+/- 12 semitones) — SliceControls.tsx
  • ✓ Reverse toggle per slice
  • ✓ Half-speed / double-speed per slice
  • ✓ Export individual WAVs + Batch ZIP export — ExportPanel.tsx
  • ✓ Choke groups (A, B, C, D) — ChokeGroupSelector.tsx
✅ Phase 3: Time & Groove
COMPLETE

Pro features fully implemented

  • ✓ BPM detection — useBPMDetection.ts
  • ✓ Time-stretch slices — TimeStretchControls.tsx
  • ✓ Swing/groove templates — grooveAmount in store
  • ✓ Slice layering — SliceLayer[] in store
🎁 Bonus Features (Beyond Spec)
+8 EXTRAS

Additional pro features not in original spec

  • ✓ ADSR Envelope per slice — Attack, Decay, Sustain, Release with presets
  • ✓ Crossfade options — Linear, Exponential, Equal-power curves
  • ✓ Warp markers — Non-uniform time-stretching like Ableton
  • ✓ Bake FX to export — Apply pitch/reverse/effects to exported WAVs
  • ✓ Volume control per slice — 0-100% gain
  • ✓ Pan control per slice — L/C/R positioning
  • ✓ Batch ZIP export — Export all slices in one download
  • ✓ AI Producer Assist context — AI knows what panel you're in

🎨 UI Design

Target interface for the upgraded Sample Chopper:

┌─────────────────────────────────────────────────────────────────────┐ │ 🎛️ SAMPLE CHOPPER [🎙️ Record] [⬇️ Export All] │ ├─────────────────────────────────────────────────────────────────────┤ │ Input: [USB Turntable ▼] Mode: [Vinyl ▼] ████████░░ -6dB │ ├─────────────────────────────────────────────────────────────────────┤ │ │ │ ▁▂▃▄▅▆▇█▇▆▅▄▃▂▁▂▃▄▅▆▇█▇▆▅▄▃▂▁ [BPM: 94.2] [🔍 Detect] │ │ | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | │ │ │ │ Chop Mode: [🎯 Auto] [📊 Grid: 8] [✂️ Manual] │ ├─────────────────────────────────────────────────────────────────────┤ │ SLICE CONTROLS: Selected: Slice 3 │ │ Pitch: [-12 ────●──── +12] Speed: [½x] [1x] [2x] │ │ [🔄 Reverse] [Choke: A ▼] [⬇️ Export WAV] [🗑️ Delete] │ ├─────────────────────────────────────────────────────────────────────┤ │ GROOVE: [None ▼] [MPC 54%] [MPC 71%] [Dilla] [SP-1200] [Custom] │ ├─────────────────────────────────────────────────────────────────────┤ │ ┌─────┐ ┌─────┐ ┌─────┐ ┌─────┐ Layer: [+] Add sound to pad │ │ │ 1 │ │ 2 │ │ ▶3◀ │ │ 4 │ Choke Groups: │ │ │ A │ │ A │ │ B │ │ B │ [A] Kicks [B] Snares │ │ └─────┘ └─────┘ └─────┘ └─────┘ [C] Hi-hats [D] Other │ │ ┌─────┐ ┌─────┐ ┌─────┐ ┌─────┐ │ │ │ 5 │ │ 6 │ │ 7 │ │ 8 │ [Send to Drum Machine] │ │ │ C │ │ C │ │ D │ │ D │ [Send to Timeline] │ │ └─────┘ └─────┘ └─────┘ └─────┘ │ └─────────────────────────────────────────────────────────────────────┘

🤖 SPARC Development Swarm

Six specialized agents will build the Sample Chopper Pro in parallel:

🎙️ Recording Agent
• Record button in Chopper UI
• Device enumeration & selection
• Vinyl mode constraints
• Live input meters
🎚️ Slice FX Agent
• Per-slice pitch shift
• Reverse toggle
• Playback rate (½x, 2x)
• Slice state management
📦 Export Agent
• Individual WAV export
• Batch export all slices
• 24-bit/48kHz encoding
• File naming convention
🔇 Choke Groups Agent
• Choke group logic (A-D)
• Stop others on trigger
• Visual group indicators
• Group assignment UI
⏱️ BPM/Groove Agent
• BPM detection (essentia.js)
• Swing templates (MPC, Dilla)
• Custom groove editor
• Quantize triggers
🎛️ Time-Stretch Agent
• Granular time-stretch
• Length without pitch
• Slice layering
• GrainPlayer integration

📁 File Structure

New and modified files for Sample Chopper Pro:

src/ ├── components/ │ └── SampleChopper/ │ ├── SampleChopper.tsx # Main component (modify) │ ├── ChopperWaveform.tsx # Waveform display (modify) │ ├── SlicePads.tsx # Pad grid (modify) │ ├── ChopperRecorder.tsx # NEW: Recording UI │ ├── SliceControls.tsx # NEW: Pitch/reverse/speed │ ├── GrooveSelector.tsx # NEW: Swing templates │ ├── DeviceSelector.tsx # NEW: Audio input picker │ └── InputMeter.tsx # NEW: Level meters │ ├── hooks/ │ ├── useMicrophoneRecording.ts # Modify for vinyl mode │ ├── useSlicePlayback.ts # NEW: Per-slice audio │ ├── useBPMDetection.ts # NEW: Tempo analysis │ └── useChokeGroups.ts # NEW: Choke logic │ ├── stores/ │ └── chopperStore.ts # NEW: Slice state, settings │ ├── utils/ │ ├── transientDetection.ts # Existing (keep) │ ├── grooveTemplates.ts # NEW: MPC/Dilla presets │ └── timeStretch.ts # NEW: Granular stretch │ └── audio/ └── encoders/ └── wavEncoder.ts # Existing (use for export)

📦 Technical Dependencies

Feature Technology Status
Device selection navigator.mediaDevices.enumerateDevices() Native API ✓
Audio recording MediaRecorder + getUserMedia() Already using ✓
Pitch shift Tone.PitchShift Already using ✓
Reverse/speed Tone.Player (reverse, playbackRate) Already using ✓
WAV export wavEncoder.ts Already have ✓
BPM detection essentia.js or web-audio-beat-detector essentia worker exists ✓
Time-stretch Tone.GrainPlayer or soundtouch-js Need to add
Groove templates Custom algorithm (offset arrays) Need to build

📈 Success Metrics

⏱️
Time to First Chop
Record → first slice playing
Target: < 10 seconds
🖱️
Click Count
Arm → Record → Chop flow
Target: 4-5 clicks max
🔄
Repeat Sessions
Device remembered between visits
Target: Zero config
📊
Audio Quality
Preserve vinyl character
Target: 48kHz/24-bit WAV

📅 Development Timeline

1
Phase 1: Record Into Chopper
1-2 days — Device selection, vinyl mode, live meters, auto-load
2
Phase 2: Slice Manipulation
2-3 days — Pitch, reverse, speed, export WAVs, choke groups
3
Phase 3: Time & Groove
3-5 days — BPM detection, time-stretch, swing templates, layering

📚 Research Documents

Detailed research created by the specialist swarm: