# DeepPluck V0.6.0 Unison & Stereo Width — Implementation Report

Date: 2026-08-30

Repository: `D:\0A_VST_Development`

Branch: `master`
Status: **automatable DoD complete; manual V0.6.0 verification pending**

## 1. Executive Summary

V0.6.0 adds a deterministic, fixed-allocation Unison and Stereo Width engine inside each of the existing 16 musical voices. One musical voice now contains one to four internal slots; every slot runs both existing PolyBLEP saw oscillators with shared detune, pan, and phase rules. Transient and Noise remain single centred sources per musical voice. The existing mono filter state was expanded to independent left/right filter states controlled by the same Filter Envelope and parameter values.

The complete automatable Definition of Done passed. A final Visual Studio 2026 fresh configuration, clean Debug and Release rebuild, 17/17 CTests in both configurations, metadata inspection, artifact hash comparison, process/window smoke, headroom matrix, stereo metrics, and Release CPU smoke all passed. No file under `JUCE/` and no protected start-side user file was changed or staged.

Human listening, interactive GUI operation, Cubase project recall/automation, host mono, and Cubase CPU evaluation remain explicitly pending. No system VST3 installation was performed.

## 2. Milestone Scope

Implemented:

- one to four fixed internal Unison slots per existing musical voice;
- symmetric Detune and Stereo Spread;
- fixed deterministic phase offsets;
- both existing oscillators in every internal slot;
- `N^-0.95` Unison normalization;
- true stereo per-voice filtering;
- centred single Transient and Noise layers;
- common Amp and Filter Envelopes;
- stereo residual fade during voice stealing;
- exact three-parameter APVTS extension, migration, presets, editor controls, tests, builds, and documentation.

Not implemented: Phase Spread parameter, redundant Unison bypass, random phase, Unison modes, modulation matrix, effects, randomization, oversampling subsystem, or final GUI redesign.

## 3. Start-Gate and Manual V0.5.0/Resonance Confirmation

The user explicitly confirmed `0.5.1 ist ok und läuft` after the V0.5.0 second-oscillator and resonance-compensation work. This confirmation was used as the required manual V0.5/resonance acceptance gate.

Before V0.6 source work, the resonance changes were isolated, rebuilt, tested as 13/13 CTests in both Debug and Release, and committed separately as:

- `a44749226ffb21bc80ba7809c09b8daffcf834bc` — `fix: compensate filter resonance loudness`

V0.6 therefore did not mix predecessor changes into its feature commit.

## 4. Normative Sound-Manifest Decisions

`Docs/Sound/DeepPluck_Sound_Manifest_v1.0.md` was read before implementation and remained normative. The selected design supports the emotional deep-house pluck identity through restrained fresh defaults, deterministic rather than random phase, limited four-slot density, centred attack layers, bounded coherent gain growth, stable pitch centre, and a deliberately narrow parameter surface.

The design avoids aggressive supersaw behavior: maximum detune is 30 cents, fresh Detune is 4 cents, fresh Spread is 35%, and Tight Pluck remains a complete mono reference.

## 5. Starting Branch, Commit, and Repository Protection

- Starting branch: `master`
- Clean V0.5-plus-resonance base: `a44749226ffb21bc80ba7809c09b8daffcf834bc`

Protected start-side untracked paths and unchanged SHA-256 values:

| Path | SHA-256 |
|---|---|
| `CubaseTest/DeepPluckTest.cpr` | `513C642FFFC3A2A0EE148C7D8D72C94C10B4413AE74D1491FE8CFD4A9EAC293C` |
| `Docs/DeepPluck_V0.2.0a_Master_Prompt_Rev1.txt` | `D9FBC1AC0F427E85FEBA3001018FB7A180AB3AA9BEFB23E9345FDCE215C6A9AC` |
| `Docs/DeepPluck_V0.2.0b_MasterPrompt_Rev1.txt` | `7485ED397B1B2541D8F3062F141388B4A31F4496465031535E2A989B9E398B4D` |
| `Docs/DeepPluck_V0.5.0_Second_Oscillator_MasterPrompt_Rev1.txt` | `FE239DD85257ADDF1C77562414EA44126CE71EB23FCAA38C9A0D495458B8115A` |
| `Docs/DeepPluck_V0.6.0_Unison_Stereo_Width_MasterPrompt_Rev1.txt` | `F955FBF5E8EC1FF1AA3029ACD36195E8C282E65F7AC0CBDF382D651EAC0B51B7` |

The files remained untracked and unstaged. `git diff --name-only -- JUCE` was empty. `build/` and `Artifacts/` remained ignored.

## 6. Plugin Identity and Version

The project and plugin version are 0.6.0. These identities are unchanged:

- vendor: ToneTrax;
- manufacturer code: `Tntx`;
- plugin code: `DpV1`;
- bundle identifier: `de.tonetrax.deeppluck`;
- product/plugin name: DeepPluck;
- VST3 component CID: `ABCDEF019182FAEB546E747844705631`;
- VST3 controller CID: `ABCDEF011234ABCD546E747844705631`;
- no-input/stereo-output instrument, MIDI input, no MIDI output;
- VST3 and Standalone formats.

Both VST3 `moduleinfo.json` files and both Standalone Windows resources report 0.6.0. A clean target rebuild was required after inspection found stale 0.5.0 Standalone resource libraries left by an earlier incremental build; the clean rebuild corrected both resources before final acceptance.

## 7. Parameter Table with All 32 IDs

The first 29 IDs and positions are unchanged. The new values are append-only at positions 30–32.

| # | ID | Range | Fresh default | Legacy value |
|---:|---|---:|---:|---:|
| 1 | `outputGain` | -60..+6 dB | -3 dB | existing |
| 2 | `masterTune` | 420..460 Hz | 440 Hz | existing |
| 3 | `ampAttack` | 0.001..5 s | 0.003 s | existing |
| 4 | `ampDecay` | 0.001..5 s | 0.320 s | existing |
| 5 | `ampSustain` | 0..1 | 0 | existing |
| 6 | `ampRelease` | 0.001..10 s | 0.180 s | existing |
| 7 | `filterEnabled` | off/on | on | existing |
| 8 | `filterCutoff` | 20..20000 Hz | 1800 Hz | existing |
| 9 | `filterResonance` | 0..1 | 0.18 | existing |
| 10 | `filterDrive` | 0..18 dB | 3 dB | existing |
| 11 | `filterKeyTracking` | 0..1 | 0.35 | existing |
| 12 | `filterEnvAmount` | -5..+5 oct | +2.50 oct | existing |
| 13 | `filterAttack` | 0.001..5 s | 0.002 s | existing |
| 14 | `filterDecay` | 0.001..5 s | 0.280 s | existing |
| 15 | `filterSustain` | 0..1 | 0 | existing |
| 16 | `filterRelease` | 0.001..10 s | 0.180 s | existing |
| 17 | `transientEnabled` | off/on | on | existing |
| 18 | `transientLevel` | -60..0 dB | -18 dB | existing |
| 19 | `transientDecay` | 0.001..0.100 s | 0.012 s | existing |
| 20 | `transientTone` | 0..1 | 0.55 | existing |
| 21 | `noiseEnabled` | off/on | on | existing |
| 22 | `noiseLevel` | -60..0 dB | -27 dB | existing |
| 23 | `noiseDecay` | 0.005..1.500 s | 0.120 s | existing |
| 24 | `noiseTone` | 0..1 | 0.35 | existing |
| 25 | `osc2Enabled` | off/on | on | existing |
| 26 | `osc2Level` | -60..0 dB | -15 dB | existing |
| 27 | `osc2Octave` | -1..+1 integer | 0 | existing |
| 28 | `osc2Semitone` | -12..+12 integer | 0 | existing |
| 29 | `osc2FineTune` | -50..+50 ct | -7 ct | existing |
| 30 | `unisonVoices` | 1..4 integer | 2 | 1 |
| 31 | `unisonDetune` | 0..30 ct, 0.1 step, centre skew 5 ct | 4 ct | 0 ct |
| 32 | `stereoSpread` | 0..1, 0.001 step | 0.35 | 0 |

## 8. Unison Module Ownership and Fixed Allocation

`DeepPluckUnison` owns fixed `std::array` storage for four primary oscillators, four secondary oscillators, four multiplicative Detune smoothers, four left pan smoothers, and four right pan smoothers. No internal slot is allocated or freed during playback.

One played MIDI note remains one `DeepPluckVoice`; the synthesizer still owns exactly 16 preallocated musical voices and one sound.

## 9. Detune Formula and Tables

For maximum detune `D` and factor `f[N][i]`:

```text
ratio_i = 2^((D * f[N][i]) / 1200)
```

| N | Factors |
|---:|---|
| 1 | `0` |
| 2 | `-1, +1` |
| 3 | `-1, 0, +1` |
| 4 | `-1, +1, -1/3, +1/3` |

Every table has zero arithmetic mean in cents. Detune zero yields ratio 1 for every active slot. Ratios are smoothed multiplicatively over 20 ms.

## 10. Stereo Pan Law, Tables, and Orientation

| N | Pan positions |
|---:|---|
| 1 | `0` |
| 2 | `-1, +1` |
| 3 | `-1, 0, +1` |
| 4 | `-1, -1/3, +1/3, +1` |

Orientation is `+1` or `-1` from `(voiceIndex + midiNote) % 2`. For spread `S`:

```text
p = panPosition[N][i] * S * orientation
leftGain  = sqrt(max(0, 1 - p))
rightGain = sqrt(max(0, 1 + p))
```

Pan gains are recalculated only for target changes and linearly smoothed over 20 ms. Spread zero settles to left/right gain 1 for every slot.

## 11. Phase and Determinism Contract

| N | Phase offsets |
|---:|---|
| 1 | `0` |
| 2 | `-1/16, +1/16` |
| 3 | `-1/12, 0, +1/12` |
| 4 | `-3/32, -1/32, +1/32, +3/32` |

Oscillator 1 starts at `wrap01(offset)`. Oscillator 2 starts at `wrap01(0.25 + offset)`. Automation changes targets without resetting phase. Identical voice index, MIDI, parameters, sample rate, and block data produce bit-identical direct renders; stereo 512-sample output also matched an 8 × 64 partition within the existing `1e-7` tolerance.

## 12. Gain Compensation Formula and Measurements

Each slot sum is multiplied by:

```text
normalization = N^-0.95
```

| N | Normalization | Worst coherent factor `N * normalization` |
|---:|---:|---:|
| 1 | 1.000000 | 1.00000 |
| 2 | 0.517632 | 1.03526 |
| 3 | 0.352156 | 1.05647 |
| 4 | 0.267943 | 1.07177 |

There is no limiter, clipper, peak detector, signal-dependent gain, or hidden output auto-gain.

## 13. Final Stereo Signal Flow

```text
MIDI -> one block parameter snapshot -> one of 16 musical voices
  -> 1..4 fixed Unison slots
       -> Oscillator 1 + Oscillator 2
       -> common slot detune, deterministic phase, pan, N^-0.95
  -> tonal left/right
  -> add one centred Transient sample and one centred Noise sample
  -> left/right dry branches
  -> two independent filters with identical controls and one Filter Envelope value
  -> one Amp Envelope value, velocity, fixed voice gain
  -> stereo residual fade when stolen
-> complete stereo voice sum -> one smoothed global Output Gain
```

## 14. Oscillator-1/Oscillator-2 Integration

Every internal slot contains both PolyBLEP saws. The same slot detune ratio multiplies both base frequencies, preserving Oscillator 2 Octave/Semitone/Fine-Tune relationships. Oscillator 2 Level and bypass smoothers remain shared across slots. Bypassed Oscillator 2 instances continue phase advancement.

## 15. Filter and Resonance-Compensation Integration

Left and right filters have independent histories and identical cutoff, resonance, drive, key tracking, bypass, and Filter Envelope control values. The confirmed 24 dB characteristic and resonance compensation remain unchanged:

```text
compensation = min(2.5, 1 + 1.5 * resonance^2)
```

Final Release regression metrics:

- filter stopband slope: 24.2165 dB/octave;
- minimum compensated high-resonance passband RMS ratio: 0.542022 (-5.31966 dB);
- isolated maximum filter stress peak: 3.08514, finite and intentionally not hidden.

## 16. Envelope, Transient, and Noise Integration

Filter Envelope and Amp Envelope are evaluated once per sample and musical voice, then applied identically to both channels. Transient and Noise each render once per musical voice and are added with the same sample to left and right. A differential integration test measured zero centred-layer stereo error within `1e-7`.

## 17. Voice-Count Latching and Live Smoothing

Unison Voices is read at Note-On and latched in the active musical voice. A held note keeps its old count; a new or stolen note reads the current count. Detune and Spread remain live for held notes. Detune ratios use 20 ms multiplicative smoothing; pan gains use 20 ms linear smoothing. Repeated target changes continue from current values.

## 18. Voice-Stealing, MIDI Timing, and Stereo Residual Fade

The existing free/released-quietest/quietest selection remains unchanged. A hard steal stores both last rendered channel values and fades each over two milliseconds while the new note starts immediately. The 17th-note maximum-Unison test retained exactly 16 musical voices, latched the new count, produced stereo content, and remained finite. Existing exact MIDI-offset and lifecycle suites passed unchanged.

## 19. Realtime-Safety Review

The audio path adds only fixed arrays, bounded loops of maximum four slots, smoother advancement, oscillator processing, and two existing filter instances. There is no new allocation, collection growth, lock, I/O, logging, GUI access, APVTS string lookup, ValueTree work, or entropy acquisition in `processBlock` or voice/sample rendering. Atomic pointers remain bound outside the hot path and loaded once into one validated snapshot per processor block.

`exp2` and square roots for Unison targets run only when Note-On initializes targets or when Detune/Spread targets actually change, not in the unchanged per-sample path.

## 20. State Migration Matrix V0.1.0–V0.6.0

- V0.1 through complete V0.5 with no V0.6 ID: existing values follow previous rules; V0.6 values become `1 / 0 / 0`.
- Partial V0.6 with at least one new ID: supplied values survive; missing new values receive `2 / 4 / 0.35`.
- Full V0.6: all 32 values round-trip deterministically.
- Invalid/non-finite values: existing root rejection and bounded fallback logic remain active.

Old states therefore do not become wider, detuned, phase-shifted, or Unison-normalized.

## 21. Factory Presets and Musical Rationale

| Preset | Voices | Detune | Spread | Rationale |
|---|---:|---:|---:|---|
| Deep Pluck | 2 | 4 ct | 35% | subtle fresh width |
| Soft Pluck | 3 | 6 ct | 50% | softer spatial density |
| Tight Pluck | 1 | 0 ct | 0% | exact mono reference |
| Long Pluck | 4 | 9 ct | 75% | clearly wider sustained voice |

Names, order, and previous 29 values are unchanged. Deep Pluck equals all fresh defaults. Preset matching and application include all 32 values.

## 22. GUI Changes

The functional editor adds one `UNISON & WIDTH` section with Voices, Detune, and Stereo Spread attachments, values, units, and tooltips. The Voices tooltip explains new-note-only count changes. Detune and Spread are visually softened at Voices 1.

An initial 1180 × 1070 layout exceeded a 1080p desktop once the native window frame was included. Visible screenshot inspection caught the clipped bottom row. The final editor is 1180 × 1000 with compacted rows; a final 1182 × 1028 native-window screenshot showed every section and control inside the window. Editor construction leaves all 32 values unchanged.

## 23. Automated Test Coverage

Seventeen CTest suites now run:

`parameters`, `oscillator`, `envelope`, `filter`, `filter_envelope`, `transient_noise`, `transient_noise_integration`, `oscillator2`, `oscillator2_integration`, `unison`, `unison_integration`, `headroom`, `performance`, `synthesiser`, `sample_accuracy`, `matrix`, and `smoothing_stability`.

Coverage includes exact parameter order/types/ranges/defaults, all migration cases, preset values/matching, Detune/Pan/Phase tables, normalization, phase continuity, smoothing, count latching, mono return, measured width, centred layers, stereo filters, deterministic block partitioning, stereo stealing, both oscillators, all earlier filter/envelope/source regressions, headroom, extreme automation, sample rates, block sizes, and CPU.

The functional matrix is 44.1/48/96 kHz crossed with block sizes 1, 17, 32, 64, 127, 512, and 1024, including MIDI events at relevant offsets.

## 24. Headroom, Mono, Mid/Side, and Peak Measurements

Final Debug and Release DSP values matched at the printed precision.

Unison count measurements use 48 kHz, a 16-note fresh-default chord, 9 ct/75% for counts above one:

| Voices | Peak | RMS | Left peak | Right peak | Left RMS | Right RMS | Mid/mono RMS | Side RMS | Mono peak |
|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:|
| 1 | 0.268460 | 0.0254889 | 0.268460 | 0.268460 | 0.0254889 | 0.0254889 | 0.0254889 | 0 | 0.268460 |
| 2 | 0.254029 | 0.0202614 | 0.254029 | 0.222455 | 0.0206602 | 0.0198546 | 0.0193029 | 0.00615823 | 0.229133 |
| 3 | 0.262126 | 0.0196070 | 0.262126 | 0.219474 | 0.0199867 | 0.0192197 | 0.0191359 | 0.00427179 | 0.239811 |
| 4 | 0.265880 | 0.0202885 | 0.265880 | 0.224764 | 0.0204707 | 0.0201048 | 0.0199756 | 0.00354981 | 0.245146 |

The dedicated wide four-note render measured left RMS 0.0543808, right RMS 0.0557435, and left-minus-right RMS 0.0238825. Voices 1/Spread 0 was exact dual mono.

The complete Fresh Default plus all four factory presets were rendered at 44.1/48/96 kHz with 1/4/8/16 notes. Worst peaks across that matrix:

| Scenario | Worst peak |
|---|---:|
| Fresh Default | 0.256507 |
| Deep Pluck | 0.256507 |
| Soft Pluck | 0.124791 |
| Tight Pluck | 0.473075 |
| Long Pluck | 0.137962 |

Additional sustained-default 16-note peak: 0.544045.

Maximum V0.6 extreme-test peak: 0.733950.

Confirmed V0.5-plus-resonance baseline extreme peak: 0.870790.
All complete-synth results remain below 0.95 and finite.

## 25. CPU/Performance Measurements

The automated benchmark renders 96 × 256 frames after eight warm-up blocks and reports the median of three trials at 48 kHz.

Final Release results:

| Scenario | Median time | Frames/s | Relative time |
|---|---:|---:|---:|
| 16 musical voices, both oscillators, Unison 1 | 20.3912 ms | 1,205,230 | 1.00000 |
| 16 musical voices, both oscillators, Unison 2 | 23.2380 ms | 1,057,580 | 1.13961 |
| 16 musical voices, both oscillators, Unison 4 | 31.1974 ms | 787,758 | 1.52994 |
| 16 musical voices, Oscillator 1 only, Unison 4 | 32.2613 ms | hardware-run value | 1.58114 vs Unison-1/both reference |
| 1 musical voice, both oscillators, Unison 4 | 1.9300 ms | hardware-run value | 0.09465 vs 16-voice reference |

The required Release 4-Unison/1-Unison extreme ratio is 1.52994, below the 8.0 ceiling. Absolute timing is hardware-specific. Cubase host CPU remains manual.

## 26. Debug Build and CTest Result

Final clean Debug build:

- generator: Visual Studio 18 2026, x64;
- compiler: MSVC 19.51.36256.0;
- SDK selected: 10.0.26100.0;
- full clean build wall time: approximately 35 seconds;
- compiler errors: 0;
- new compiler warnings: 0;
- CTest: 17/17 passed in 8.69 seconds.

## 27. Release Build and CTest Result

Final clean Release build:

- generator: Visual Studio 18 2026, x64;
- compiler: MSVC 19.51.36256.0;
- SDK selected: 10.0.26100.0;
- full clean build wall time: approximately 47.5 seconds;
- compiler errors: 0;
- new compiler warnings: 0;
- CTest: 17/17 passed in 1.68 seconds.

The final successful fresh configure took approximately 7.3 seconds. `COPY_PLUGIN_AFTER_BUILD` remains `FALSE`.

## 28. Produced Local Artifacts and Metadata

| Configuration | Artifact | Bytes | SHA-256 |
|---|---|---:|---|
| Debug | VST3 inner binary | part of 24,824,894-byte bundle | `3D3BF188DB6C16C87FEA7360CC2CFFD55F9D45D7E4BC64ADA0C4D08244A1C852` |
| Debug | Standalone | 27,210,752 | `0193EFF0AEF7BBEEBC11AD19F271BC995CFDD8C24C20994819404675FEEB2EB6` |
| Release | VST3 inner binary | part of 7,808,574-byte bundle | `099A6E538445E102B018AE58276A373521867F1DDCD7FAF3BFBBF464CC33AED3` |
| Release | Standalone | 8,989,184 | `E877015F0244A2C947D993D4EFA4B0EEDC43D6453B3B9D91C3176B354C80173C` |

Build outputs exist under `build/DeepPluck_artefacts/{Debug,Release}` and project-local copies under `Artifacts/{Debug,Release}`. Each VST3 bundle contains the binary and `moduleinfo.json`. Per-file bundle comparison and Standalone SHA-256 comparison both returned equal for Debug and Release.

The usual system paths `C:\Program Files\Common Files\VST3`, `C:\Program Files\Steinberg\VSTPlugins`, and `C:\Program Files\VSTPlugins` contained no `DeepPluck.vst3`. No automatic system installation occurred.

## 29. Standalone Smoke Tests

Final Debug and Release Standalones both:

- started successfully;
- created a responsive native window titled `DeepPluck`;
- displayed `Development Build V0.6.0`;
- displayed the Unison Voices, Detune, and Stereo Spread controls;
- showed all six editor sections without clipping at 1180 × 1000 client size;
- passed the automated editor-construction state-equivalence check;
- accepted a normal close request;
- exited normally within five seconds;
- left no lingering DeepPluck process.

The screenshot inspection and process smoke are not an audio listening test. Interactive tooltip, drag, and host-automation behavior remains part of manual verification.

## 30. Listening-Test Results

**MANUAL VERIFICATION REQUIRED - LISTENING TESTS**

External blocker: this implementation session has no human auditory perception and cannot truthfully judge perceived width, tonal centre, transient focus, loudness, mono collapse, or musical quality through the installed audio hardware. A person must complete the 14 listening checks in the master specification with Release Standalone or Cubase and record audio interface, sample rate, buffer, notes/chords, preset, observation, and pass/fail.

## 31. Cubase Validation and Host-CPU Result

**MANUAL VERIFICATION REQUIRED - CUBASE VALIDATION**

Cubase 12, 13, 14, and 15 installations were detected, but no Cubase process was running and no V0.6 VST3 bundle was installed into a system/host-visible path. Automatic installation is prohibited, and no separate authorization to copy the bundle into a system VST3 directory was used. The protected `CubaseTest/DeepPluckTest.cpr` was not modified.

Still required: scan/identity, old-project recall with 29 existing automation lanes, 32-value state recall, Detune/Spread automation, new-note-only count behavior, mono/stereo buses, complete-engine playback, realtime/offline bounce, multiple instances, and host CPU comparison.

## 32. Documentation Changes

- `README.md`: current V0.6 status, 32 controls, migration, presets, build/test coverage, 1180 × 1000 editor, Cubase checklist, limitations.
- `ARCHITECTURE.md`: ownership, tables/formulas, stereo signal flow, migration, presets, realtime and regression contracts.
- `AGENTS.md`: confirmed reference milestone updated to V0.6.0.
- `CMakeLists.txt`: version/description, Unison sources, and 17-suite registration.
- this implementation report.

## 33. Known Limitations and Explicit Out-of-Scope Items

- PolyBLEP reduces but does not eliminate aliasing.
- Unison has one deliberate fixed algorithm and maximum four slots.
- No phase/randomization control, alternate waveforms, modulation matrix, effects, oversampling subsystem, or final artwork was added.
- Host-sample-accurate parameter queues remain outside the block-snapshot architecture.
- Human listening, interactive host automation, old Cubase project recall, and Cubase CPU remain pending.

## 34. Definition-of-Done Status

Automatable items complete:

- Sound Manifest and start gate honored;
- base isolated in Git and protected files unchanged;
- version/identity/bus/MIDI contracts verified;
- exactly 16 musical voices and maximum four fixed internal slots;
- exact 32-parameter append-only contract and migration;
- deterministic Detune/Pan/Phase/normalization implementation;
- true stereo filters, common envelopes, centred layers, stereo stealing;
- 20 ms smoothing and Note-On count latching;
- presets, Custom matching, GUI attachments and state-neutral editor construction;
- 44.1/48/96 kHz, block, headroom, extreme, regression, and performance suites;
- final fresh configure, clean Debug/Release builds, 17/17 CTests in each;
- correct 0.6.0 metadata, local artifacts, hash equality, no system installation;
- process/window Standalone smoke;
- clean diff checks, ignored build/artifact paths, no `JUCE/` change, no push.

Manual items pending:

- listening acceptance;
- interactive GUI/tooltips/control operation;
- Cubase scan, project recall, state and automation;
- human mono compatibility and perceived loudness;
- Cubase host CPU.

Status remains: **automatable DoD complete; manual V0.6.0 verification pending**.

## 35. Git Commits and Final Repository Status

Implementation commit:

- `dcb1c3d73a68d7faf11f7a1c28ba51c94ba8568a` — `feat: add unison and stereo width engine`

Report commit:

- `docs: add V0.6.0 implementation report`

The report commit's immutable hash cannot be embedded inside its own content without changing that hash recursively. Its final hash is recorded by the post-commit `git log` and in the implementation task's final response. No history was rewritten and nothing was pushed.
