Add IPA vocal tract roadmap

docs/ipa-vocal-tract-roadmap.md

@@ -0,0 +1,426 @@
+# IPA Vocal Tract Roadmap
+
+AquaSynth can get close to a Pink Trombone-class tract model, then move past it
+by treating IPA as an authoring input rather than the synth itself. The machine
+we want is not a giant table from symbol to sound. It is a pipeline:
+
+```text
+IPA text
+  -> phonetic tokens
+  -> language phonology profile
+  -> timed articulatory gesture plan
+  -> morphology-specific tract and excitation curves
+  -> Faust DSP
+  -> rendered speech, song, chant, and nonhuman vocalization
+```
+
+The target user feeds Weksa text as IPA or IPA-like phonetic strings. AquaSynth
+keeps the real authority below that surface: phonetic features, gestures,
+anatomy, excitation, and acoustic simulation.
+
+## Objective
+
+Build a research-grounded vocal-tract instrument for human and alien speech:
+
+- parse IPA into structured phonetic intent;
+- lower phonetic intent through a language profile into articulatory gestures;
+- render those gestures through human and nonhuman tract morphologies;
+- keep coarticulation continuous rather than stepping between phoneme presets;
+- make every layer testable with mocks, fixtures, and deterministic outputs;
+- grow supported IPA exponentially as the tract model earns new physics.
+
+The Weksa goal is conlang speech rendering for Zyphos worldbuilding. IPA gives
+authors a familiar entry point. The tract model gives us the power to make Weksa
+sound like Weksa instead of like English wearing ceremonial markup.
+
+## Research Spine
+
+The first implementation should stand on old, durable work:
+
+- Kelly-Lochbaum / digital waveguide vocal tract models simulate 1D wave
+  propagation through connected tube sections using reflection coefficients.
+  This is the practical spine behind Pink Trombone-like realtime tract synthesis.
+- Pink Trombone demonstrates that a simplified tract, glottis, turbulence, oral
+  cavity, and nasal coupling can produce interactive intelligible speech-like
+  sound in realtime.
+- Liljencrants-Fant-style glottal source models give a better voiced excitation
+  than a naive sawtooth or pulse train, and can parameterize voice quality.
+- Articulatory phonology and task dynamics provide the right control model:
+  phonetic units become overlapping gestures, not isolated frames.
+- Vocal-tract area-function work is the middle layer between anatomy and DSP:
+  vowels and constrictions can be expressed as cross-sectional area over tract
+  distance before being lowered to reflection coefficients.
+- IPA feature databases and phoneme-table implementations are reference
+  material for metadata, not authorities over the sound. They help keep the
+  parser and feature mapper honest while the gesture and morphology layers own
+  synthesis.
+- Source-filter speech theory still matters, but this lane should not collapse
+  back into static formant filters. Formants are useful diagnostics; tract shape
+  is the synthesis authority.
+
+Useful starting sources:
+
+- Pink Trombone / Neil Thapen interactive tract model:
+  <https://dood.al/pinktrombone/>
+- Pink Trombone overview at IMAGINARY:
+  <https://www.imaginary.org/program/pink-trombone>
+- Recent Pink Trombone optimization paper describing PT as a realtime
+  Kelly-Lochbaum tract model:
+  <https://link.springer.com/article/10.1186/s13636-025-00414-5>
+- Story 2005 vocal-tract area-function model:
+  <https://bpb-us-e2.wpmucdn.com/sites.arizona.edu/dist/f/80/files/2023/10/story_jasa2005-1.pdf>
+- Kelly-Lochbaum / time-domain articulatory synthesis summary:
+  <https://www.isca-archive.org/eurospeech_1989/owens89b_eurospeech.html>
+- Waveguide vocal tract acoustics:
+  <https://eprints.whiterose.ac.uk/id/eprint/3713/>
+- Voice source model comparison including LF:
+  <https://pmc.ncbi.nlm.nih.gov/articles/PMC4491021/>
+- LF model fitting for speech synthesis:
+  <https://www.cs.cmu.edu/~awb/papers/is2013/is2013_lfmodel.pdf>
+- Haskins TADA gestural planning model:
+  <https://www.haskinslaboratories.org/tada>
+- PanPhon IPA feature vectors:
+  <https://pypi.org/project/panphon/>
+- PHOIBLE phoneme inventories and distinctive features:
+  <https://phoible.org/>
+- eSpeak NG phoneme-table implementation reference:
+  <https://deepwiki.com/espeak-ng/espeak-ng/4.2-phoneme-model>
+
+## Architecture
+
+### 1. IPA Parser
+
+Owns Unicode IPA tokenization and notation, not sound.
+
+Inputs:
+
+- IPA string;
+- optional language tag;
+- optional inline stress, length, tone, syllable, and boundary marks.
+
+Outputs:
+
+- ordered `PhoneticToken` records;
+- diacritic attachments;
+- suprasegmental marks;
+- source spans for diagnostics.
+
+The parser should be table-driven and deterministic. It should reject unknown
+clusters with useful diagnostics instead of guessing heroically and making a new
+little bureaucracy out of Unicode.
+
+### 2. Phonetic Feature Mapper
+
+Owns IPA-to-feature interpretation.
+
+Examples:
+
+- `/p/` -> voiceless bilabial stop;
+- `/ɬ/` -> voiceless alveolar lateral fricative;
+- `/qʼ/` -> uvular ejective stop;
+- `/aː/` -> long open vowel, front/central depending on profile defaults.
+
+Outputs:
+
+- `PhoneticSegment` with manner, place, voicing, airstream, length, stress,
+  vowel height/backness/rounding, and diacritics.
+
+This layer should support language profiles. IPA has broad and narrow uses, and
+Weksa may assign phonemic categories to articulatory targets that are only
+human-adjacent. PanPhon, PHOIBLE, and eSpeak NG are useful references for feature
+schemas and inventory sanity checks, but AquaSynth should own its feature record
+instead of importing a third-party schema as the permanent internal model.
+
+### 3. Gesture Planner
+
+Owns time and coarticulation.
+
+Inputs:
+
+- phonetic segments;
+- language timing profile;
+- prosody vector;
+- speaking style;
+- morphology capability map.
+
+Outputs:
+
+- overlapping gestures for tract constriction, tongue body, tongue tip, lips,
+  velum, glottis, pressure, turbulence, burst release, and auxiliary organs.
+
+This is where consonants and vowels smear into each other. Stops close before
+their release. Vowels pull neighboring consonants. Fricatives hold a narrow
+constriction and noise source. Nasals open a branch. Ejectives and clicks become
+pressure/airstream events rather than cute punctuation.
+
+The gesture planner should resemble a small task-dynamics compiler: phone
+features become overlapping constriction tasks and source events. It should not
+linearly interpolate phone presets unless a test proves that shortcut works for
+the current stage.
+
+### 4. Morphology Model
+
+Owns anatomy.
+
+Human baseline:
+
+- tract length;
+- section count;
+- palate/tongue mapping;
+- lip opening/protrusion;
+- velum and nasal branch;
+- one glottal source;
+- oral tract radiation.
+
+Alien/Weksa extensions:
+
+- longer or shorter tract families;
+- asymmetric or split oral branches;
+- additional resonant sacs;
+- secondary glottal or membrane exciters;
+- nonhuman nasal/side-channel coupling;
+- constrained articulator ranges by species or caste;
+- morphology-specific mappings from human IPA-like features to physical organs.
+
+IPA does not get to own alien anatomy. IPA names intent; morphology realizes it.
+
+### 5. Tract DSP
+
+Owns sound.
+
+First spine:
+
+- 1D Kelly-Lochbaum-style tube sections;
+- reflection coefficients from section area;
+- glottal excitation at the source;
+- lip radiation;
+- nasal branch switch/coupling;
+- turbulence injection at constriction points;
+- closure and burst primitives for stops.
+
+Use area functions as the stable middle representation: a morphology and gesture
+plan produce tract-area curves over time; the DSP compiler turns those curves
+into reflection coefficients, source injection points, and coupling events.
+
+Later spine:
+
+- losses and dispersion;
+- lip/larynx impedance refinements;
+- side branches and sacs;
+- multiple sources;
+- differentiable or search-assisted parameter fitting for vowel targets;
+- morphologies that are not merely scaled human throats.
+
+Generated Faust should remain boring enough to inspect. If tract DSP becomes
+large, generate a specialized Faust module from a typed tract plan instead of
+stuffing a hundred magic controls into ordinary `voice`.
+
+## Supported IPA Roadmap
+
+Do not support all IPA first. That is the trap where the parser looks mighty and
+the synth says five ugly vowels. Expand by doubling the useful surface each time
+the physical model earns another category.
+
+### Stage 0: Token Spine
+
+Goal: lossless-enough IPA tokenization and diagnostics.
+
+Support:
+
+- whitespace and word boundaries;
+- `/.../` and `[...]` wrappers;
+- primary and secondary stress;
+- length marks `ː` and `ˑ`;
+- common tie mark for affricates;
+- combining diacritic storage without full interpretation.
+
+Tests:
+
+- round-trip token spans;
+- unknown-symbol diagnostics;
+- diacritic attachment fixtures.
+
+### Stage 1: Vowels And Simple Voice
+
+Goal: intelligible sustained vowel targets through a human tract.
+
+Support:
+
+- monophthong vowels: `i y ɨ ʉ ɯ u ɪ ʏ ʊ e ø ɘ ɵ ɤ o ə ɛ œ ɜ ɞ ʌ ɔ æ ɐ a ɶ ɑ ɒ`;
+- length and stress as duration/prosody modifiers;
+- modal voiced glottal source;
+- simple pitch, intensity, and breathiness controls.
+
+Machine growth:
+
+- vowel feature space;
+- tract area targets informed by area-function references;
+- glottal source model;
+- vowel fixture renderer.
+
+Validation:
+
+- check approximate formant regions for `/i e a o u ə/`;
+- compare tract-area curves against known vowel-shape expectations;
+- keep listening fixtures because a formant table can still lie with confidence.
+
+### Stage 2: Core Pulmonic Consonants
+
+Goal: CV, VC, and CVC syllables with recognizably different places and manners.
+
+Support:
+
+- stops: `p b t d k g ʔ`;
+- nasals: `m n ŋ`;
+- fricatives: `f v s z ʃ ʒ h`;
+- approximants: `w j l ɹ`;
+- basic aspiration `ʰ`;
+- syllable and word timing.
+
+Machine growth:
+
+- closure/release events;
+- plosive burst noise;
+- fricative turbulence source;
+- nasal branch;
+- simple coarticulation curves.
+
+Validation:
+
+- verify voice onset timing for stops;
+- verify burst timing and broad noise bands;
+- verify nasal/oral contrast;
+- reject fricative support that is only a filtered noise preset with no
+  constriction/source location.
+
+### Stage 3: Expanded Human IPA
+
+Goal: useful conlang coverage without pretending to be a universal phonetician.
+
+Support:
+
+- places: dental, alveolar, postalveolar, retroflex, palatal, velar, uvular,
+  pharyngeal, glottal;
+- manners: trills, taps/flaps, lateral fricatives, lateral approximants,
+  affricates;
+- symbols: `θ ð ɕ ʑ ç ʝ x ɣ χ ʁ ħ ʕ ɸ β ʂ ʐ ɲ ɳ ɴ ɾ r ʀ ɭ ʎ ʟ ɰ`;
+- affricate tie sequences such as `t͡s`, `d͡ʒ`, `t͡ɬ`;
+- voiceless/voiced and dentalized/palatalized/labialized/velarized diacritics
+  where they map to real gestures.
+
+Machine growth:
+
+- tongue tip/body split;
+- lateral constriction;
+- trill/tap event generators;
+- profile-specific place maps.
+
+This is the point where a language profile starts earning its keep. The same IPA
+symbol may need different timing, place bias, or allophonic behavior by language;
+that belongs in the profile, not in the global token parser.
+
+### Stage 4: Airstream And Phonation
+
+Goal: Weksa can use sounds that feel physically intentional instead of being
+ornamental apostrophes.
+
+Support:
+
+- ejectives: `ʼ`;
+- implosives: `ɓ ɗ ʄ ɠ ʛ`;
+- clicks: `ʘ ǀ ǃ ǂ ǁ`;
+- breathy, creaky, slack/stiff voice diacritics;
+- voiceless vowels and sonorants;
+- tone marks if Weksa needs lexical or prosodic tone.
+
+Machine growth:
+
+- pressure reservoirs;
+- glottal closure timing;
+- ingressive/egressive event modeling;
+- richer glottal source parameterization;
+- non-pulmonic test fixtures.
+
+### Stage 5: Weksa And Alien Morphologies
+
+Goal: IPA can drive nonhuman vocal anatomy without reducing aliens to exotic
+human accents.
+
+Support:
+
+- morphology profiles with declared organ inventory;
+- feature remapping per morphology;
+- unsupported-feature diagnostics that explain the missing organ or gesture;
+- dual-source phonation;
+- resonant sacs and side branches;
+- nonhuman lateral or split-tract continuants;
+- authored Weksa phoneme inventories and allophones.
+
+Machine growth:
+
+- morphology capability negotiation;
+- tract graph beyond a single tube plus nasal branch;
+- multi-source DSP;
+- Weksa fixture corpus;
+- Zyphos scene hooks for speaker, body, place, and emotional pressure.
+
+## Testing And Mocking
+
+The implementation should be built as a set of injectable services:
+
+- `IIpaTokenizer`
+- `IPhoneticFeatureMapper`
+- `IPhonologyProfile`
+- `IGesturePlanner`
+- `ITractMorphology`
+- `ITractPlanCompiler`
+- `ITractFaustEmitter`
+- `IAudioRenderer`
+- `IReferenceFixtureStore`
+
+Mock seams are not ceremony here. They protect the machine:
+
+- tokenizer tests do not need DSP;
+- feature tests do not need coarticulation;
+- gesture tests can snapshot control curves;
+- morphology tests can assert capabilities and remaps;
+- Faust emitter tests can verify generated structure without rendering;
+- renderer tests can compare short deterministic buffers;
+- Weksa profile tests can prove unsupported IPA fails clearly.
+
+Golden fixtures:
+
+- IPA tokenization fixtures;
+- feature bundle fixtures;
+- gesture-plan JSON fixtures;
+- tract-area curve fixtures;
+- rendered vowel and CVC WAV artifacts;
+- Weksa phrase fixtures once the language profile exists.
+
+Metrics:
+
+- formant target distance for vowels;
+- envelope and burst timing for stops;
+- noise-band distance for fricatives;
+- nasal/oral spectral contrast;
+- intelligibility/listening notes for complete syllables;
+- script/IPA terseness only after audio is credible.
+
+## First Work Packets
+
+1. Add `docs/ipa-vocal-tract-roadmap.md` and preserve the boundary doctrine.
+2. Add an IPA tokenizer and feature model with Stage 0/1 fixture tests.
+3. Add a human baseline vowel planner that emits tract-area targets, not audio.
+4. Add a tiny tract renderer prototype in AquaSynth.Faust or a test-only lab
+   lane, then decide the package boundary once the prototype proves itself.
+5. Render five vowels and three CVC syllables through fixtures.
+6. Add the first Weksa phonology profile with explicit unsupported-feature
+   diagnostics.
+7. Only then add Stage 2 consonant synthesis to the shipping path.
+
+## Non-Goals
+
+- Full CFD, finite-element airflow, or anatomical medical simulation.
+- A black-box neural TTS voice that hides anatomy and cannot explain itself.
+- A complete IPA parser before the tract can render basic syllables.
+- Alien sounds as random effects. Nonhuman output needs morphology, not glitter.

docs/reference-synth-roadmap.md

@@ -51,6 +51,29 @@ missing graph feature instead of smuggling it through unrelated parameters.
 
 ## Target Families
 
+### New Lane: IPA Vocal Tract / Weksa
+
+This is not merely another reference synth. It is a new authoring and rendering
+lane: IPA text lowers into phonetic features, timed articulatory gestures,
+morphology-specific tract/excitation curves, and Faust DSP. The roadmap lives in
+[`docs/ipa-vocal-tract-roadmap.md`](ipa-vocal-tract-roadmap.md).
+
+Pressure on AquaSynth DSL:
+
+- IPA as an input surface, not an internal patch model.
+- Phonology profiles separated from tract morphology.
+- Gesture planning and coarticulation before audio rendering.
+- Human and alien vocal anatomies driven by the same structured phonetic intent.
+- Mockable tokenizer, feature mapper, gesture planner, morphology, emitter, and
+  renderer seams.
+
+First deliverable:
+
+- Stage 0/1 IPA tokenization and vowel feature fixtures.
+- Human baseline vowel tract-area planner.
+- A small render proof that can say a few vowels before the supported IPA table
+  expands.
+
 ### Tier 1: DX7/Dexed
 
 Use this first. DX7 SysEx is compact, structured, and musically meaningful:

state/evidence.jsonl

@@ -104,3 +104,4 @@
 {"date":"2026-05-17","topic":"zyn-formant-parity-fixtures","lesson":"The first formant-motion parity workout needs multiple multi-frame ADD/formant fixtures and a real Zyn ADD note oracle. Avoid letting drum-kit envelope/source failures masquerade as formant evidence. Use Wide Bass, Ghost Ensemble, and Ghost Choir as the initial chorus; all currently fail enough to be useful.","evidence":"Added test-only `tools/zyn-reference/ZynVoiceReference.cpp`, wired it into the MSYS reference build, and added `ZynVoiceReferenceRendererSurveysUpstreamFormantFixturesWhenBuilt`. The batch writes ignored artifacts under `artifacts/parity/zyn-upstream-formant-fixtures/`; baseline scores were Wide Bass 0.280990, Ghost Ensemble 0.312813, Ghost Choir 0.363644. The native Zyn reference build succeeded and the focused formant fixture test passed."}
 
 
+{"date":"2026-05-19","evidence":"Added docs/ipa-vocal-tract-roadmap.md with staged IPA support from tokenization/vowels through pulmonic consonants, expanded IPA, airstream/phonation, and Weksa alien morphologies; linked it from docs/reference-synth-roadmap.md and state.","lesson":"AquaSynth should treat IPA as an authoring input for phonetic intent, not as the internal synth model. The planned machine is tokenizer -\u003e feature mapper -\u003e phonology profile -\u003e gesture planner -\u003e morphology -\u003e tract plan -\u003e Faust renderer, growing supported IPA only as tract/excitation physics earn each category.","topic":"ipa-vocal-tract-roadmap"}

state/map.yaml

@@ -16,6 +16,7 @@ surfaces:
   patch_library: patches
   tests: tests/AquaSynth.Dsl.Tests
   reference_roadmap: docs/reference-synth-roadmap.md
+  ipa_vocal_tract_roadmap: docs/ipa-vocal-tract-roadmap.md
   faust_toolchain_boundary: docs/faust-toolchain-boundary.md
   dx7_public_domain_fixtures: tests/AquaSynth.Dsl.Tests/Fixtures/Dx7/PublicDomain
   zyn_reference_source: external/zynaddsubfx
@@ -36,6 +37,7 @@ modules:
   dx7_reference_render_tests: tests/AquaSynth.Dsl.Tests/Dx7ReferenceParityTests.cs
   zyn_reference_reader: src/AquaSynth.Core/ZynInstrument.cs
   zyn_coverage_survey: src/AquaSynth.Core/ZynInstrument.cs
+  ipa_vocal_tract_roadmap: docs/ipa-vocal-tract-roadmap.md
   package_boundary_tests: tests/AquaSynth.Dsl.Tests/PackageBoundaryTests.cs
   sfxr: src/AquaSynth.Core/SfxrParams.cs
   analysis: src/AquaSynth.Core/AudioAnalysis.cs
@@ -57,6 +59,7 @@ boundaries:
     - Faust source generation in AquaSynth.Core
     - target-code generation, compile-product contracts, dynamic patch compilation policy, cache identity, generated artifact manifests, and Faust toolchain selection in AquaSynth.Faust
     - live patch compilation, native Faust factory lifetime, and offline sample-buffer render proof in AquaSynth.Faust
+    - IPA-to-phonetic-feature planning, articulatory gesture planning, and human/alien vocal-tract roadmap design
   dev_only:
     - public-domain DX7 SysEx fixtures
     - pinned GPL ZynAddSubFX source for parity tests

state/memory.json

@@ -79,10 +79,16 @@
       "ZynAddSubFX instruments for additive, subtractive, PAD, formant, and layered patches",
       "Faust examples/libraries for general DSP graph topology",
       "Surge XT for modern hybrid synth modulation",
-      "Cardinal/VCV-style patches for modular cable/rate semantics"
+      "Cardinal/VCV-style patches for modular cable/rate semantics",
+      "IPA/Weksa vocal tract synthesis for phonetic gesture planning, human and alien tract morphologies, and conlang speech rendering"
     ],
     "rule": "Add DSL abstractions only when reference rebuilds prove the missing invariant. Do not consume references that cannot be backed by parity tests; parsing alone is inventory, not evidence of expressivity."
   },
+  "ipa_vocal_tract_path": {
+    "status": "Roadmap drafted for an IPA-to-vocal-tract lane. IPA is an authoring input only: tokenization and feature mapping lower into language phonology profiles, timed articulatory gestures, morphology-specific tract/excitation curves, and Faust DSP. The staged support plan starts with tokenization and vowels, then core pulmonic consonants, expanded human IPA, airstream/phonation, and Weksa/alien morphologies.",
+    "lesson": "Do not build a complete IPA parser before the tract can say basic syllables. The durable machine is tokenizer -> feature mapper -> phonology profile -> gesture planner -> morphology -> tract plan -> Faust renderer, with dependency-injected seams and mocks at each boundary. Weksa should use IPA-like phonetic input without letting human IPA semantics own alien anatomy.",
+    "next": "Implement Stage 0/1 fixtures: IPA token spans, vowel feature bundles, human baseline vowel tract-area targets, and a tiny render proof before expanding consonants."
+  },
   "dx7_reference_path": {
     "status": "DX7 SysEx parser extracts voice edit buffers, packed voices, packed 32-voice banks, six operators, envelopes, algorithm, feedback, oscillator sync, LFO, transpose, voice name, checksum validation, ReferencePatch features, algorithm topology from the reverse-engineered OPS algorithm ROM table, envelope-to-ADSR approximations, measured carrier output amplitude, isolated two-op modulation route scale, summed/cascaded route scale, calibrated feedback amount table, ratio detune lowering, voice transpose lowering, fixed-frequency operator lowering, ROM COM output compensation cut, operator key/rate scaling at the effective played note, topology-aware route lowering, staged operator envelopes with per-segment curves, raw and block-interpolated DX7 envelope tracing, applied-envelope curved lowering with optional sustain floor, two AquaSynth DSL rebuild attempts, first-class OperatorGraph support with graph-level vibrato, public-domain SysEx fixture coverage, dexed-py reference rendering, project-authored Dexed patch rendering, AquaSynth candidate rendering through Faust-generated C#, one thresholded rendered parity test for analog1.syx voice 13, a hard PRC SYNTH1 parity probe with listening WAV artifacts and log-mel <= 0.145, project-authored algorithm-8 summed-stack/cascade/summed-pair parity, rendered community parity for Mooger, Piano Bass, RES SYNTH1, and ANLGSYN 1 with a sustained high-band gate, a MELLOWSOLO pressure artifact test, and renderable delayed operator feedback.",
     "lesson": "Algorithm 32's additive six-carrier shape maps cleanly to six AquaSynth voices. Algorithm 8 justified OperatorGraph: operators, modulation edges, carriers, feedback, and graph-level pitch motion belong to a graph authority, not Voice fields. The first rendered parity rung is behavioral and sine-like, not exact DX7 operator execution. A harder algorithm-8 target exposed that feedback must be delayed recursion in Faust, not a direct cyclic self-reference. Static DX7 output-level approximation helped import/rebuild math but was mathematically wrong for carrier amplitude. A single-carrier Dexed sweep shows carrier amplitude follows 2^((outputLevel - 99) / 8). Isolated two-op DX7 FM maps full-level modulation to AquaSynth route index 6.275; summed/cascaded algorithm-8 branches now use 6.0 after PRC listening, a project-authored combined stack probe, and split cascade/summed-pair probes showed lower values were under-bright. Feedback lowers through a fitted table instead of PRC-local constants; ANLGSYN 1 showed max feedback value 7 needs a hotter AquaSynth amount 2.2 to recover buzzy high bands, while value 5 remains 0.19 for PRC. ANLGSYN 1 then exposed a sustained-buzz gap: output soft clip helped but did not stop mid-note drift; max-feedback source operators need an applied-envelope sustain floor so the feedback loop stays driven after the attack. ANLGSYN 1's remaining beat is pitch LFO: AMD is nonzero but all operator AMS values are 0, while PMD/PMS lower cleanly to operator-graph vibrato with faded delay. Ratio-mode detune belongs in operator frequency lowering. DX7 voice transpose belongs in graph base frequency: transpose 24 is neutral, transpose 12 lowers MIDI note 60 to 130.8128 Hz. DX7 fixed-frequency operators are absolute Hz, not note ratios; ANLGSYN 1 proved fixed op1/op3 must lower to ratios around 0.007615/0.009227 against a 130.8128 Hz graph base to preserve low buzzing modulation. ROM COM carrier compensation was cut: user listening found no-COM renders harmonically closer and mainly too quiet, so `OperatorOutputCompensation` returns unity and graph gain owns loudness recovery. Operator key-scaling and rate-scaling must lower against the effective played MIDI note after transpose; hardcoded MIDI 60 made RES SYNTH1 too soft on attack and Piano Bass less harmonically accurate. Project-authored Dexed patch rendering now gives lawful calibration targets. Reusing the operator output curve for EG levels was tested and cut because it failed hard-target log-mel; later output-level-dependent and naive traced-release applied-envelope experiments were also cut because they worsened broader parity. Direct envelope tracing shows current linear `env=rl` cannot express DX7 EG spike/drop behavior. Dexed-style audio samples EG once per 64-sample block and interpolates applied gain, so raw EG parity alone is not audio parity. Staged operator envelopes now support linear/exponential segments and supranormal levels. `ApproximateAppliedRateLevelEnvelope` uses that surface and now picks the first near-peak before gate so slower rising modulators hit early instead of swelling late; it can also preserve a floor for max-feedback source sustain. Community gains with no COM and played-note scaling: Mooger 0.75, Piano Bass 0.72, RES SYNTH1 0.75. Algorithm-2 non-carrier applied envelopes currently cap the first peak at 0.92 to prevent ANLGSYN 1/RES SYNTH1 peak blowout while preserving Piano Bass. MELLOWSOLO is a pressure artifact test, not passing parity; its render window is 1.25s so the candidate release is audible instead of cut at the artifact boundary. Mooger needs a more aggressive attack contour, and RES SYNTH1's phase-like attack issue is likely relative operator attack/peak shape because oscillator sync is enabled. PRC remains passing on log-mel/envelope/RMS, with score floor lowered to 0.74 after rate scaling changed the aggregate score.",