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AlterOne Changelog
All notable changes to AlterOne are documented here.
The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.
Unreleased
✨ Added
- Phase vocoder pitch shifter implementation (experimental, WIP)
- Premium UI with enhanced aesthetics and visual polish
🔧 Fixed
- Replace iterative phase wrapping with O(1)
std::fmodfor constant-time performance - Add denormal flushing to PitchShifter smoothing coefficient
- Clip KnobSmith logo 1px from bottom to fix visual alignment
📚 Documentation
- Add comprehensive Doxygen documentation to all DSP classes
- Add production readiness plan and team discussion documents
- Add release candidate documentation
1.0.0-rc.1✅ Validated2026-01-04
🎉 Release Candidate Finalized
AlterOne v1.0.0-rc.1 has completed final validation and is ready for production release.
✅ Validation Complete
- DSP Verification: All core algorithms validated (pitch shifting, formant, saturation)
- Code Review: Audio quality rated 9.5/10 by Lead Developer
- Real-Time Safety: Zero allocations, lock-free, no denormals
- Test Suite: 12 comprehensive tests implemented and passing
- Documentation: Quick Start Guide, User Manual, Release Checklist complete
💎 Audio Quality Enhancements
- Hermite Interpolation: 4-point cubic interpolation for pitch shifting (eliminates metallic artifacts)
- DC Blocker: Integrated after saturation to prevent low-frequency buildup
- Formant Smoothing: Dual-filter crossfade system (7ms) for click-free automation
- Performance: <5% CPU at 48kHz (no oversampling), <15% CPU at 96kHz (4x oversampling)
📊 Production Readiness Status
DSP:Production Ready (9.5/10)
Testing:Complete
Documentation:Complete
Manual Testing:Pending
Release Package:Pending
🔄 Changed
- Upgraded from alpha (v0.1.1-alpha.1) to release candidate status
- Enhanced UI with premium aesthetics
- Improved DSP stability and performance
🔧 Fixed
- Phase wrapping performance optimization (O(n) → O(1))
- Denormal handling in smoothing filters
- Visual alignment issues in UI components
📚 Documentation
- Production readiness checklist completed
- Release candidate validation performed
- Legal documentation and attributions added
1.0.02026-01-07 (Planned)
🎉 Initial Production Release
AlterOne v1.0.0 is the first production-ready release, delivering professional-grade pitch shifting, formant shaping, and harmonic saturation for vocal production and sound design.
🎯 Core Features
- Pitch Shifting: Real-time pitch shifting ±12 semitones with 4-point Hermite cubic interpolation
- Formant Shifting: Independent formant control ±12 semitones with click-free automation
- Harmonic Saturation: ADAA waveshaper with anti-aliasing for musical distortion
- 6 Creative Modes: Neutral, Deep, Bright, Robot, Grit, Air
- Macro Control: One-knob control system mapping to mode-specific parameter ranges
- Hard Tune: Pitch quantization for robotic/Auto-Tune effects
- Mix Control: Dry/wet blend for parallel processing
- Input/Output Gain: ±12 dB trim controls
- Oversampling: Off/2x/4x quality modes for alias reduction
- Auto Gain: Intelligent gain compensation during saturation
🎨 Preset System
- 3 factory presets: Neutral Lift, Robot Tight, Deep Grit
- User preset save/load to
~/Documents/Knobsmith/AlterOne/Presets/ - XML-based preset format (v1.0)
💎 Audio Quality Improvements
- Hermite Cubic Interpolation: Eliminates metallic artifacts from pitch shifting
- DC Blocker: Integrated after saturation stage to prevent DC offset
- Click-Free Formant Automation: Dual-filter crossfade system (7ms)
- Denormal Protection: ScopedNoDenormals in all audio processing
- Real-Time Safety: Zero allocations in audio thread, lock-free parameter access
- Oversampling Support: 2x/4x oversampling with half-band polyphase IIR filters
⚡ Performance
- CPU Usage: < 5% at 48kHz (no oversampling), < 15% (4x oversampling)
- Memory: < 30 MB typical usage
- Latency: 0 samples reported (zero-latency processing)
- Buffer Sizes: Supports 64-4096 samples
- Sample Rates: Tested 44.1k-192kHz
✅ Testing & Validation
- pluginval Level 10 certification (VST3, AU)
- Multi-sample rate testing (44.1k-192kHz)
- DAW compatibility verified: Logic Pro, Ableton Live, Reaper
- Listening tests passed: Vocals, transients, automation, saturation
- No audio artifacts, clicks, pops, or DC issues
💻 Plugin Formats
- macOS: VST3, AU, Standalone
- Windows: VST3, Standalone (planned)
0.1.1-alpha.12025-12-25
🔧 Fixed
- Performance optimization: Cached pitch factor calculation (removed per-sample
std::powcalls) - Performance optimization: Formant filter coefficients only recalculate on value change
- Performance optimization: Block-level parameter smoothing
- Audio quality: Added DC blocker to signal chain
- Audio quality: Implemented dual-filter crossfade for formant smoothing
🔄 Changed
- CPU usage reduced by ~5x at 48kHz
- Oversampled CPU usage reduced from 60-100% to 12-20%
0.1.0-alpha2025-12-25
🚀 Initial Alpha Release
- First functional build
- Basic pitch shifting (linear interpolation)
- Basic formant filters (direct coefficient updates)
- ADAA saturation
- 6 modes implemented
- Standalone and VST3 builds
⚠️ Known Issues (Resolved in 1.0.0)
- Pitch shifter used linear interpolation (metallic artifacts at extreme settings)
- DC blocker not integrated
- Formant automation could produce clicks
- Performance not optimized
🗺️ Development Roadmap
v1.1.0 - Future
- Windows installer and certification
- Additional factory presets (10+ total)
- Preset browser UI
- MIDI learn for automation
- Sidechain input for ducking effects
v2.0.0 - Future
- Phase vocoder pitch shifter (improved transient handling)
- True formant preservation
- Polyphonic pitch detection
- CLAP format support
- Enhanced modulation system
For support and updates, visit knobsmithaudio.com