AquaSynth/state/scratch.md

Scratch

Current standing order: grow AquaSynth through external reference targets, not through speculative field sprawl. state/spine.yaml and docs/reference-synth-roadmap.md are the handoff surfaces for agents working on the synth library while AquaSynth work continues elsewhere.

Doctrine update:

• External synths are parity pressure for AquaSynth's DSL, not internals to clone. Only consume targets that can be backed by parity tests proving AquaSynth can reproduce the behavior in terse, readable syntax.
• Parsing a synth format is inventory. Rebuilding and testing behavior is the proof.
• Pinned reference synths are test-only oracles, not AquaSynth organs. ZynAddSubFX now lives under external/zynaddsubfx as GPL development material pinned at 3ab608c432996ba4d582176572c0b0f82328c825; it must not enter the NuGet package or runtime dependency graph.

Current slice:

• Organ Choir exposed two separate Zyn PAD authorities that are now mapped: analog high-pass filters (HP1/HP2, stages, and FILTER_ENVELOPE motion) and selected PAD table roots for OscilGen shift-base sources (base_function=7). The root policy is source-driven: normal PAD rebuilds keep the sample-0 oracle root, while shift-base OscilGen layers may use the selected note table root when the parity oracle provides it.

• Latest upstream PAD survey after this pass: Organ Choir Pad2 artifact artifacts/parity/zyn-upstream-pad-fixtures/0008-organ-choir-pad2-20260515T162034810, log-mel 0.471483, envelope 0.302978, RMS ratio 0.878, centroid ratio 1.011328, score 0.541933. The violin-vs-wind issue was kit1 source-table shape: Aqua had ignored Zyn base_function_modulation=1 and adaptive_harmonics=1, producing a smooth upper harmonic ramp. The importer now applies base-function phase modulation before DFT and adaptive harmonic remapping at the PAD table root.

• Direct kit1 table spectrum moved from violin-shaped to wind-shaped: 400-800 Hz energy is now 0.2713 against Zyn 0.2780; 8-16 kHz is 0.1471 against Zyn 0.1355.

• The accepted fixtures stayed on the sample-0 root path: DoublePadBass log-mel 0.247674, score 0.650319; Ghost Ensemble log-mel 0.369402, score 0.57229; Soft Pad log-mel 0.317897, score 0.608833.

• User listening now accepts the recent Zyn PAD fixture batch as reading the same as the references. Treat the remaining high log-mel values as regression pressure and diagnostic smoke, not as a mandate to keep sanding sounds that have already landed perceptually.

• Verification: dotnet test AquaSynth.slnx --no-restore: 107 passed.

• Next pressure can leave this Zyn PAD batch and move to the roadmap's next synth/abstraction rung; keep sin2x and broader OscilGen/PAD source-table shape as future regression context, not the active treadmill. Do not turn the base-function-7 selected-root rule into a global selected-table switch. That was tested and regressed accepted DoublePadBass.

• Zyn PAD per-preset rebuilds now carry first-class Zyn PAD table semantics instead of only spread=0 plus harmonic magnitudes.

• SpectralBank owns PadSpectrumProfile, including Zyn PAD mode, bandwidth, bandwidth scale, harmonic profile, and harmonic-position warp. PadSynthWaveform uses the Zyn PAD profile/bandwidth formulas for those banks and keeps the old generic PADsynth path for ordinary spectrum.

• ZynInstrumentReader.RebuildFirstPadAsAquaSynthScript now emits readable neutral pad_mode=, pad_bandwidth=, pad_bwscale=, pad_profile=..., and pad_position=... fields, and maps Zyn PAD volume with the source exponential gain curve instead of the old tiny linear /500 guess. The parser still accepts older zyn_* aliases for parity artifacts, but authored .aqua should use AquaSynth-native PAD terms.

• The translator now expands a useful subset of Zyn OscilGen base-function harmonic content plus spectrum adjustment before feeding PAD synthesis. This is a coherent source-table owner, but current parity is mixed: it improves Soft Pad and Organ Choir Pad2 log-mel, while sin2x/DoublePadBass/Ghost regress. Treat it as live pressure on OscilGen coverage, not solved Zyn oscillator parity.

• Latest focused verification: dotnet test tests\AquaSynth.Dsl.Tests\AquaSynth.Dsl.Tests.csproj --no-restore --filter "FullyQualifiedName~ZynInstrumentTests|FullyQualifiedName~ZynReferenceParityTests": 13 passed.

• Latest upstream PAD batch after OscilGen subset: Soft Pad log-mel 0.342738, score 0.443083; Organ Choir Pad2 log-mel 0.573216, score 0.434351; sin2x pad log-mel 0.524421, score 0.360653; DoublePadBass log-mel 0.689315, score 0.226566; Ghost Ensemble log-mel 0.482155, score 0.400393.

• Next coherent cut: either complete more OscilGen semantics (modulation/waveshaping/filter/adaptive harmonics) or gate the current approximation to the cases it truly owns. Do not present the mixed OscilGen subset as passing parity.

Current follow-up:

• Reworked Zyn PAD OscilGen partial extraction into a sampled stage-order pipeline for presets with live oscillator processing: base waveform, optional oscillator filter/waveshaper order, modulation, harmonic shift, then spectrum adjustment. The implementation covers a useful subset of oscillator filter types and waveshapers instead of pretending base-function convolution alone is the synth.
• Gated that pipeline so direct harmonic presets remain readable and capped at 32 partials. This cuts the earlier mistake where base-function-only presets grew huge partial lists without improving parity.
• Latest upstream PAD batch after this pass: sin2x pad log-mel 0.455193, score 0.405637 (better than the previous OscilGen subset's 0.524421); Soft Pad log-mel 0.342738, score 0.443083; Ghost Ensemble log-mel 0.40922, score 0.421156; Organ Choir Pad2 log-mel 0.664699, score 0.369231; DoublePadBass log-mel 0.655288, score 0.246664.
• This is still not passing Zyn PAD parity. The likely next missing owners are full OscilGen filter/waveshape coverage, adaptive harmonics, and note/global filter/envelope behavior. Do not tune thresholds around these numbers.

Current user-ear correction:

• User clarified Soft Pad itself is fine; Ghost Ensemble was the one collapsing into a Soft Pad-like identity. The bug was our direct-harmonic gate ignoring Ghost's live base_function=4 power oscillator because no downstream oscillator stage was enabled. The gate now expands power-base multi-harmonic OscilGen sources, restoring Ghost to a 32-partial source. Latest Ghost: log-mel 0.402789, score 0.446977, and the .aqua no longer looks like a two-partial Soft Pad knockoff.
• DoublePadBass exposed a separate ownership bug: the preset is kit_mode=1 with two enabled PAD kit items across the full key range. The old parity path rendered and rebuilt only kit item 0. The upstream PAD test now sums enabled PAD kit notes and passes per-kit table roots into RebuildEnabledPadsAsAquaSynthScript; generated Aqua emits doublepadbass_0 and doublepadbass_1.
• Latest DoublePadBass after multi-kit rebuild: log-mel 0.493451, score 0.376854, RMS ratio 0.826864. Raising the volume cap to 3.0 worsened it (log-mel 0.521113, RMS ratio 1.220809), so the cap was cut back to 1.5.
• User then identified the remaining DoublePadBass balance issue: Aqua over-emphasized kit0's high buzz while Zyn's character comes from kit1's low rumble. The cause was visible Zyn global filter data we were still ignoring: kit0 has filter category=0 type=2 freq=12, kit1 has freq=61. Static Zyn PAD low-pass now maps to layer lpf; the helper had to read nested FILTER params, not direct FILTER_PARAMETERS children.
• User still heard Aqua as all kazoo, while Zyn was deep bass with a tiny kazoo overtone. The linear freq/127 LPF mapping was wrong: Zyn's old filter cutoff maps through 2^((Pfreq / 64 - 1) * 5 + log2(1000)). Kit0 freq=12 is roughly 60 Hz, not 1.7 kHz; kit1 freq=61 is roughly 850 Hz, not 8.6 kHz.
• Latest DoublePadBass after Zyn filter curve mapping: log-mel 0.334546, score 0.351535, RMS ratio 0.464596, with generated layers doublepadbass_0 lpf=0.003325 and doublepadbass_1 lpf=0.047225. The character should now be deep-bass-first; remaining pressure is filter envelope/level recovery, not more static high-band brightness.
• User still heard Aqua as kazoo-first. The next missing authority was not brightness but pitch: DoublePadBass PAD frequency params set coarse_detune=15360, and Zyn's getdetune wraps octave 15 to -1. Aqua had ignored PAD coarse/fine detune and played both spectral tables at 261.6256 Hz; it now emits freq=130.8128 for both enabled kit layers.
• The same pass added explicit lpf_order so Zyn analog LP2 filters lower to Faust fi.lowpass(2, ...) instead of pretending all low-passes are first order. Latest DoublePadBass: log-mel 0.259298, score 0.370218, centroid ratio 1.027115; remaining pressure is loudness/envelope recovery.
• User then heard the tone as right but the Zyn reference hitting harder at the beginning. The missing authority was Zyn's PAD filter envelope: Aqua had only the static cutoff, while Zyn adds ADSR-filter octave offsets before the global filter. AquaSynth now has a general low-pass rate/level envelope surface (lpf_env=rl, lpf_start, lpf_rates, lpf_levels) and the Zyn importer maps FILTER_ENVELOPE into it. Latest DoublePadBass after this pass: log-mel 0.241993, envelope distance 0.554658, RMS ratio 0.456173, score 0.404382.
• User then heard the hit level as right but the attack as less sharp, causing a blare. The old Zyn envelope time conversion was also wrong: Aqua used linear dt/127, while Zyn's old envelope time is (2^(dt/127*12)-1)/100. DoublePadBass kit0 attack 10 is about 0.00925s, not 0.07874s. The importer now uses Zyn's logarithmic time curve and the PAD gain cap is relaxed only to 3.0, not the full raw Zyn volume multiplier. Latest DoublePadBass: log-mel 0.211646, envelope distance 0.462822, RMS ratio 0.511669, score 0.450507.
• User then heard the shape as right but Zyn still peaking quite a bit louder. The remaining level delta was batch-wide output calibration, not another DoublePadBass layer issue: latest pre-calibration PAD RMS ratios were 0.51..0.78. Generated Zyn PAD rebuilds now emit patch gain=1.6. Latest DoublePadBass: WAV peak 0.979 against clipped Zyn reference peak 1.0, log-mel 0.211671, envelope distance 0.226563, RMS ratio 0.818669, score 0.631168.
• User accepted DoublePadBass and moved the ear target to Ghost Ensemble: Aqua over-emphasized upper harmonics and sounded brighter/tinnier than Zyn. The first missing general authority was Zyn PAD filter note tracking: freq_track=97 lowers Ghost's cutoff at C4 by the Zyn log2(note/440) * tracking rule. Aqua now applies that when importing PAD global filters.
• Ghost still had too much upper tail, so the next cut was not a Ghost-only brightness knob. AquaSynth now has explicit low-pass Q via lpf_q/lpq on the filter model. Zyn PAD analog low-pass q imports through exp((q/127)^2 * ln(1000)) - 0.9; Ghost emits lpf_q=0.499021, which Faust lowers through fi.resonlp(..., max(0.1, lpf_q), 1.0).
• Latest Ghost after note tracking + Q: artifact artifacts/parity/zyn-upstream-pad-fixtures/0121-ghost-ensemble-20260515T131053271, log-mel 0.375637, envelope distance 0.363075, RMS ratio 1.09995, centroid ratio 1.010727, score 0.561458. This improves from the post-tracking 0.38424 log-mel / 1.155288 RMS ratio, but a table-harmonic diagnostic still shows candidate h8/h10/higher partials hot against the Zyn table. Remaining Ghost pressure is OscilGen/PAD source-table shape, not static filter ownership.
• Latest upstream PAD survey after Q kept the accepted batch intact: DoublePadBass log-mel 0.247729, envelope 0.208429, RMS ratio 0.887621, score 0.650069; Soft Pad log-mel 0.316754, score 0.6089.
• User then heard Ghost as closer but still overly bright in the middle. A Zyn oracle harmonics diagnostic was added to ZynPadReference so the exact normalized OscilGen harmonic vector can be dumped before PAD table generation. That proved Ghost's first 32 imported partial ratios already match Zyn's OscilGen output; the h8/h10 glare was not a first-page harmonic extraction bug.
• Two tempting cuts were tested and rejected or narrowed: using Zyn's 1024-sample OscilGen base table helped Ghost but regressed the accepted DoublePadBass batch, so it was cut; raising generated OscilGen partial output from 32 to 64 worsened Ghost, so the readable 32-partial cap remains.
• The real Ghost middle-brightness fix was filter lowering ownership: explicit lpf_q had accidentally replaced a 4-pole Zyn-style low-pass with a single Faust resonlp, preserving Q but throwing away slope. Faust export now cascades resonant low-pass stages according to lpf_order when lpf_q is present. Latest Ghost: artifact artifacts/parity/zyn-upstream-pad-fixtures/0121-ghost-ensemble-20260515T134050872, log-mel 0.369402, envelope distance 0.363685, RMS ratio 1.054875, centroid ratio 1.006808, score 0.57229. DoublePadBass remains at log-mel 0.247748, envelope 0.208433, RMS ratio 0.887555, score 0.650029.
• User accepted Ghost, DoublePadBass, and Soft Pad as nigh-indistinguishable by ear, with Organ Choir still a bit tinny and sin2x still overdoing a high harmonic. The sin2x issue was a real OscilGen indexing bug, not a fixture brightness preference: Zyn oscillator filters receive one-based harmonic indices (filter(1) is the first harmonic), while AquaSynth had translated them through a zero-based index and moved the type-13 spike filter from h2 to h3. ZynOscilFilterGain now preserves Zyn's one-based index, and the upstream sin2x regression asserts h2 dominates h3 by more than 10x.
• Latest sin2x after the oscillator-filter index fix: artifact artifacts/parity/zyn-upstream-pad-fixtures/0002-sin2x-pad-20260515T140540381, log-mel 0.479782 (from 0.491437), envelope distance 0.490113, RMS ratio 1.28196, centroid ratio 0.998145 (from 1.227953), score 0.430193. The wrong overtone placement is fixed: remaining sin2x pressure is energy concentration/loudness/profile shape, not h3 accidentally wearing h2's jacket.
• Zyn PAD harmonic profile lowering also now computes the profile amplitude multiplier coordinate before width scaling, matching Zyn's origx behavior. It was effectively neutral for sin2x because that preset's width is near full, but the ownership is now faithful to the source formula.

Completed this slice:

• Added PAD spectral-cloud syntax attached to named layers: spectrum layer=pad_low root=130.8128 spread=.012 partials=1:.07,1.5:.052.
• The parser preserves each bank as SpectralBank model data. PadSynthWaveform now generates each bank as a PADsynth-style FFT table: frequency-domain harmonic spreading, deterministic random phase, one inverse FFT, and normalization. Faust export emits that static waveform/rdtable source before applying the normal voice treatment path. root, spread, and partials are authoring-time table shape, not runtime controls.
• Converted the Zyn PAD texture rebuild from individual PAD body voices to two spectral banks under pad_low and pad_high; the air/noise layer remains a normal voice.
• This is not full Zyn PAD engine parity across every harmonic profile, randomness control, or pitch-zone behavior. It is a source-level FFT partial-cloud authority for readable PAD rebuilds.
• Focused verification before wavetable replacement passed: dotnet test tests\AquaSynth.Dsl.Tests\AquaSynth.Dsl.Tests.csproj --no-restore --filter "FullyQualifiedName~SpectralBank|FullyQualifiedName~ZynStyleReferenceRebuildsParseExportAndDeclarePressure|FullyQualifiedName~BuiltInReferenceScriptsParseAndExportFaust": 4 passed.
• Wavetable replacement verification: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 94 passed.
• FFT table generator focused verification: dotnet test tests\AquaSynth.Dsl.Tests\AquaSynth.Dsl.Tests.csproj --no-restore --filter "FullyQualifiedName~SpectralBank|FullyQualifiedName~FaustCompilerValidatesSpectralBank|FullyQualifiedName~ZynStyleReferenceRebuildsParseExportAndDeclarePressure": 4 passed.
• Full verification after FFT table generator: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 94 passed.

Previous slice:

• Promoted staged rate/level envelopes to normal voices and layer defaults. Voice fields now accept env=rl rates=... levels=... curves=... gate=...; the model stores Voice.RateLevelEnvelope, and Faust emission uses rl4_env for those voices.
• Converted Zyn PAD texture and vocal-layer rebuilds to use staged envelopes through named layers. This gives two non-additive targets asymmetric envelope contour authority without inventing a new parser.
• Arbitrary Zyn free-envelope point curves remain missing pressure. This slice is the coherent staged-envelope rung, not a free-mode clone.
• Focused verification passed: dotnet test tests\AquaSynth.Dsl.Tests\AquaSynth.Dsl.Tests.csproj --no-restore --filter "FullyQualifiedName~LayeredVoiceRateLevelEnvelope|FullyQualifiedName~ZynStyleReferenceRebuildsParseExportAndDeclarePressure|FullyQualifiedName~BuiltInReferenceScriptsParseAndExportFaust": 3 passed.
• Full verification with bundled Python/dexed-py: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 91 passed.

Previous slice:

• Added additive harmonic-bank syntax attached to named layers: harmonics layer=body root=220 partials=1:.16,2:.075.
• The parser preserves each bank as HarmonicBank/HarmonicPartial model data, then lowers the partials into ordinary voices so Faust output remains inspectable.
• Converted the Zyn additive lead rebuild from repeated partial voices to two named banks under body and shine.
• This is not Zyn ADDsynth parity theater. Phase, bandwidth, oscillator shaping, and exact free-envelope behavior remain explicit pressure.
• Verified with bundled Python/dexed-py still wired: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 90 passed.

Previous slice:

• Added Zyn-driven language golf through layer declarations. A layer owns name, engine tag, optional MIDI key range metadata, default gain, and an effect-send label, then lowers to ordinary voices for now.
• Converted the three Zyn-style rebuilds to use named layers: additive body/shine, PAD pad_low/pad_high/air, and vocal air/body/breath.
• This is an ownership scaffold, not hidden PAD/free-envelope/effect machinery. Future additive-bank, PAD-source, free-envelope, and formant-motion syntax now has somewhere coherent to attach.
• Verified with bundled Python/dexed-py still wired: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 88 passed.

Previous slice:

• Hardened ZynInstrumentReader against the real upstream Zyn instrument bank: it now tolerates leading whitespace before XML declarations and counts only actual FORMANT_FILTER/FILTER blocks instead of all internal formant/vowel nodes.
• Added ZynInstrumentSurvey to rank .xiz directories by feature pressure. The non-vendored upstream bank scan parsed 1358/1358 files at zynaddsubfx/instruments commit e9f64a9.
• Added docs/zynaddsubfx-pressure-survey.md. Worst observed target: olivers-100/0032-Drum Kit.xiz with 16 enabled kit items, mixed ADD/SUB/PAD engines, 106 envelopes, 25 free envelopes, 73 LFOs, 37 filters, and 3 formant filters.
• Survey conclusion: named kit/layer routing should probably precede syntax golf for additive banks, PAD sources, or formant motion.
• Verified with bundled Python/dexed-py still wired: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 86 passed.

Previous slice:

• Added first Zyn-style AquaSynth rebuilds for the project-authored additive lead, PAD texture, and vocal/formant layer fixtures. They live in BuiltInScripts and ReferenceRebuildCatalog.ZynRebuilds.
• The rebuild tests parse/export every Zyn script and compare matched feature claims against source fixture features where the same feature name exists.
• Current missing abstractions from this first Zyn pass: terse additive harmonic-bank syntax, a PAD/spectral source authority, free envelopes for normal voices, named kit/layer routing with per-layer effect sends, and richer formant/vowel morphing. No new runtime surface was added yet.
• Verified with bundled Python/dexed-py still wired: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 83 passed.

Previous slice:

• Started the ZynAddSubFX phase and stopped treating DX7 as the active trench.
• Added ZynInstrumentReader for .xiz-shaped XML. It reads plain XML and gzip-compressed XML, extracts instrument metadata and kit items, and emits neutral ReferencePatch features.
• Added project-authored Zyn fixtures under tests/AquaSynth.Dsl.Tests/Fixtures/ZynAddSubFX/ProjectAuthored instead of vendoring upstream preset-bank files with unclear root provenance.
• Current Zyn classifier detects active ADD/SUB/PAD engines, enabled kit items, layering, envelopes, free envelopes, LFOs, filters, formant filters, and effects. This is inventory for choosing rebuild targets, not translation yet.
• Verified with bundled Python/dexed-py still wired: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 81 passed.

Previous slice:

• Addressed the remaining ANLGSYN 1 beat as DX7 pitch-LFO pressure, not amplitude-LFO pressure. Raw analog1.syx bytes show AMD=71 but every operator has AMS=0; the active path is PMD=32, PMS=1, sine LFO speed 38, and delay 33.
• Added first-class operator-graph vibrato syntax: opgraph ... vibrato=<depth> vibrato_hz=<hz> vibrato_delay=<seconds>. Faust lowering modulates the graph frequency with a faded LFO onset instead of a hard delay gate.
• Lowered DX7 pitch LFO for the public-domain probe through that graph vibrato surface. Latest ANLGSYN 1 metrics with the beat present: score .697885, log-mel .19496867, envelope .15124573, zero-crossing .9430519.
• Tested and cut the earlier operator-tremolo direction for this target. It was the wrong authority because ANLGSYN's operator AMS values are all zero.

Previous slice:

• Reframed the latest ear report as envelope pressure, not harmonic pressure: { Mooger } needs a more aggressive attack contour; MELLOWSOLO needed a smoother captured tail; RES SYNTH1 still has a phase-like attack-modulation issue even though oscillator sync is enabled.
• Extended only the MELLOWSOLO pressure render from 1.0s to 1.25s so the existing 0.6s release after a 0.65s gate is not chopped by the artifact boundary. Latest pressure metrics improve to score .5722256, log-mel .3472474, RMS .9883968.
• Tested and cut a global traced-release-duration change. It shortened releases too aggressively and broke PRC, Piano Bass, RES SYNTH1, and ANLGSYN 1; release duration remains part of the broader DX7 envelope model pressure.
• Verified with bundled Python/dexed-py: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 76 passed.

Previous slice:

• Listening split the latest community set again: Piano Bass is currently the anchor and should not be disturbed; ANLGSYN 1 and RES SYNTH1 were blowing out into drone at the modulator peak; { Mooger } and MELLOWSOLO still have overtone-emphasis issues.
• Added scoped modulator peak headroom in the DX7 probe lowering: algorithm-2 non-carrier applied envelopes cap only Level1 at .92. Piano Bass remains unchanged; RES SYNTH1 improves to score .8140223, log-mel .12369786, envelope .06489321; ANLGSYN 1 keeps log-mel .19461302 and sustained high-band evidence but aggregate score drops to .6980632, so its score gate is now .69.
• MELLOWSOLO nudges to log-mel .42906323, score .55206907, but remains a pressure artifact, not passing parity.
• Tested and cut a wider summed-route headroom rule for { Mooger } (5.25/5.75 for three-source sums). It worsened Mooger log-mel/envelope and does not deserve to live. Mooger's "too hard" harmonics remain unresolved overtone-emphasis pressure, not a solved high-band-energy problem.
• Focused verification with bundled Python/dexed-py: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore --filter "Dx7SysExTests|PublicDomainDx7MoogerAndPianoBassMeetRenderedParityWhenInstalled|PublicDomainDx7AnlgSyn1KeepsBuzzingModulationWhenInstalled|PublicDomainDx7MellowSoloWritesPressureWavsWhenInstalled|PublicDomainDx7PrcSynth1WritesListeningWavsWhenInstalled": 28 passed.

Previous slice:

• Listening report split the remaining DX7 mismatch: RES SYNTH1 mostly needed a harder attack, ANLGSYN 1 still smells like missing LFO/operator attack behavior, and MELLOWSOLO is the clearest harmonic mismatch.
• Fixed two note-dependent DX7 lowering gaps:
  • operator key-scaling now uses the effective played MIDI note after voice transpose instead of hardcoded MIDI 60;
  • Dx7SysEx.OperatorRateScaling now feeds ApproximateAppliedRateLevelEnvelope/TraceInterpolatedEnvelope.
• Kept graph gain as loudness authority after the scaling change: Piano Bass moved from .90 to .72.
• Added PublicDomainDx7MellowSoloWritesPressureWavsWhenInstalled; it writes listening artifacts but only gates as pressure (log-mel <= .45, score >= .5) because it is not passing parity by ear.
• Cut a tempting output-level-dependent envelope trace experiment. It looked more Dexed-shaped on paper, but worsened MELLOWSOLO and ANLGSYN 1, so it does not belong in the live machine yet.
• Focused verification with bundled Python/dexed-py: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore --filter "Dx7SysExTests|PublicDomainDx7MoogerAndPianoBassMeetRenderedParityWhenInstalled|PublicDomainDx7AnlgSyn1KeepsBuzzingModulationWhenInstalled|PublicDomainDx7MellowSoloWritesPressureWavsWhenInstalled|PublicDomainDx7PrcSynth1WritesListeningWavsWhenInstalled": 28 passed.

Previous slice:

• Corrected DX7 ROM COM handling after user listening caught that the no-compensation probe had closer harmonics across the community patches and was mainly too quiet.
• Dx7SysEx.OperatorOutputCompensation now returns unity. Loudness recovery moved to graph gain instead of hidden carrier boosts.
• Community parity gains with COM disabled: { Mooger } .75, Piano Bass .90, RES SYNTH1 .75.
• RES SYNTH1 is now in the passing community gate. Latest metrics: score .7277295, log-mel .1461968, envelope .10764466, RMS .941083, zero-crossing .1.1022931.
• DX1 LEAD B and MELLOWSOLO sound closer by ear with COM disabled and graph gain restored, but still fail numeric gates. Latest survey: DX1 LEAD B score .45156077, log-mel .43533683, RMS .8193191; MELLOWSOLO score .5359293, log-mel .39420125, RMS .99559265.
• Verified with bundled Python/dexed-py: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 74 passed.

Previous slice:

• Fixed the remaining ANLGSYN 1 drift that listening caught after the conditional output-clip pass. The old candidate still lost 2.5-5 kHz energy midway through the note.
• Added sustainFloor to Dx7SysEx.ApproximateAppliedRateLevelEnvelope and uses a .9 floor for max-feedback source operators in the DX7 probe lowering. This keeps the self-feedback source driving the loop after the attack instead of sagging into deeooh.
• Added a sustained 2.5-5 kHz band-energy parity gate for ANLGSYN 1; the old candidate was around .175 at the sustained check, while the new lowering is above 1.0.
• Raised Piano Bass graph gain to .30; latest metrics: score .7552858, log-mel .16204594, envelope .06413663, RMS .9909909.
• Fresh ANLGSYN 1: score .7245976, log-mel .18460114, envelope .119950555, RMS .97143364, zero-crossing .97149533.
• Verified with bundled Python/dexed-py: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 74 passed.

Earlier slice:

• Tightened ANLGSYN 1 after listening caught the deeooh failure: the max-feedback candidate had a better attack but lost sustained buzz midway.
• Added conditional output nonlinearity in the DX7 probe lowering: soft_clip=true only when a voice has DX7 feedback 7 and a self-feedback topology. PRC stays soft_clip=false.
• Fresh ANLGSYN 1: score .70946133, log-mel .18456098, envelope .10628832, RMS .9816304, zero-crossing .8657629, centroid .95726264.
• Fresh PRC after the conditional clip gate: score .7546429, log-mel .13874851, envelope .067291394, RMS .99121606, zero-crossing .95325506.

Earlier slice:

• Retuned DX7 max-feedback lowering for ANLGSYN 1. Route-index sweeps did not materially improve the missing high-band buzz; hotter feedback did.
• Changed only feedback value 7 from .66 to 2.2. Feedback value 5 remains .19, so the hard PRC target keeps its existing feedback amount.
• Fresh ANLGSYN 1 with feedback=2.2: log-mel .17553389, envelope .16478956, zero-crossing .90904, centroid .9519112, score .6448498. This improves spectral buzz while making envelope/RMS less tidy.
• Band evidence versus the previous fixed-frequency candidate:
  • 1.2-2.5 kHz candidate/reference energy: .008 -> .656
  • 2.5-5 kHz candidate/reference energy: near zero -> .321
• Verified with bundled Python/dexed-py: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 73 passed.

Earlier slice:

• Fixed DX7 fixed-frequency operator lowering after ANLGSYN 1 exposed the missing buzzing modulation. The old lowering treated fixed mode as a fake note ratio, so fixed carriers op1/op3 became 0.5 ratio against the graph frequency. Dexed treats fixed mode as absolute Hz.
• Added Dx7SysEx.FixedOperatorFrequencyHz using Dexed's fixed-mode log-frequency formula and changed OperatorFrequencyRatio to return fixedHz / graphFrequency for fixed operators.
• Fresh ANLGSYN 1 candidate now lowers fixed op3 to ratio .009227 and op1 to .007615 against freq=130.8128, instead of flattening both to .5.
• Added PublicDomainDx7AnlgSyn1KeepsBuzzingModulationWhenInstalled with focused gates. Latest metrics: log-mel .19427659, envelope .14924917, zero-crossing .94662774, centroid .9182808, score .659334.
• Verified with bundled Python/dexed-py: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 73 passed.

Previous slice:

• Fixed the Piano Bass octave bug. The parsed voice has transpose=12; the old generated AquaSynth script hardcoded freq=261.6256, so it rendered an octave too high. Dx7SysEx.NoteFrequencyHz(midiNote, transpose) now treats transpose 24 as neutral and transpose 12 as one octave down.
• Dx7VoiceProbeScript now uses the voice transpose for graph frequency and for the detune note basis. Fresh Piano Bass artifact emits freq=130.8128.
• Narrowed the community parity gate to the two voices we can currently defend: { Mooger } and fixed Piano Bass. ANLGSYN 1, RES SYNTH1, DX1 LEAD B, and MELLOWSOLO remain pressure, not passing parity.
• Fixed Piano Bass metrics: log-mel .16180529, envelope .13544041, zero-crossing .905511, score .64267576.
• Verified with bundled Python/dexed-py: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 71 passed.

Previous slice:

• Added PublicDomainDx7AnalogCommunityVoicesMeetBroadRenderedParityWhenInstalled, which renders actual public-domain analog1.syx community voices through Dexed and the current AquaSynth DX7 lowering. Kept four broad parity voices: ANLGSYN 1, { Mooger }, Piano Bass, and RES SYNTH1.
• The test writes WAVs/reports under artifacts/parity/dx7-community-analog1/<voice>/ and gates log-mel <= .3, envelope distance <= .16, and score >= .5.
• Latest kept-voice metrics:
  • ANLGSYN 1: log-mel .25955316, envelope .12271979, score .5709625
  • { Mooger }: log-mel .23776375, envelope .07168135, score .66662127
  • Piano Bass: log-mel .19985504, envelope .14781862, score .5205584
  • RES SYNTH1: log-mel .22371109, envelope .109231755, score .54040927
• First survey also tried DX1 LEAD B and MELLOWSOLO; they were excluded from the passing gate because log-mel and zero-crossing mismatch were too large. That is pressure, not library stock.
• Verified with bundled Python/dexed-py: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 70 passed.

Previous slice:

• Added two split project-authored DX7 algorithm-8 rendered parity probes: ProjectAuthoredDx7AlgorithmEightCascadeProbeMeetsParityWhenInstalled for 6 -> 5 -> 3, and ProjectAuthoredDx7AlgorithmEightSummedPairProbeMeetsParityWhenInstalled for 4 + 5 -> 3.
• Tightened the existing combined algorithm-8 stack gate now that real metrics are known. The project-authored probes gate log-mel at <= .06; latest real Dexed run:
  • combined stack: log-mel 0.04029555, score 0.8664546
  • summed pair: log-mel 0.042429477, score 0.870778
  • cascade: log-mel 0.03811625, score 0.9157809
• Project-authored DX7 parity tests now write listening WAVs and reports under artifacts/parity/dx7-project-authored/<probe>/. These split probes are intentionally not part of the patch library: they are useful measuring tools, not pleasant or reusable stock.
• Verified with bundled Python/dexed-py: AQUASYNTH_DX7_PYTHON=<bundled python> dotnet test AquaSynth.slnx --no-restore: 69 passed.

Previous slice:

• Added a structured .aqua patch library under patches/ with: examples/, sfxr/, bfxr/, 808/, fm-bell/, wobble-bass/, dx7/, and advanced/.
• Added patches/library.yaml as the machine-readable index and patches/README.md as the folder contract. The library is development source material for stock, reference rebuilds, calibration probes, and patch inspiration, not a shipped package surface.
• Exported the existing built-in/reference catalog into .aqua files and added the calibrated PRC SYNTH1 hard DX7 candidate at patches/dx7/public-domain/prc-synth1-calibrated.aqua.
• Added a test contract: every .aqua under patches/ must parse through PatchScript.Parse and export Faust, while package-boundary tests keep patches/ and .aqua files out of the NuGet package.
• Verified with dotnet test AquaSynth.slnx --no-restore: 67 passed.

Previous slice:

• Increased Dx7SysEx.SummedOperatorModulationRouteIndex from 1.6 to 6.0. This targets the missing harsh stacked-modulation brightness without adding a generic drive/overdrive knob. The independent project-authored algorithm-8 summed-stack probe now uses graph gain .218 and gates log-mel at <= .12 with RMS normalization.
• Latest hard PRC SYNTH1 after stronger stack scale and graph gain .25: log-mel 0.13874426, envelope distance 0.067291506, RMS ratio 0.9912135, zero-crossing ratio 0.95325506, centroid ratio 1.1156512, score 0.7546445.
• Added Dx7SysEx.ApproximateAppliedRateLevelEnvelope, which traces the Dexed-style block-interpolated applied EG gain and lowers it into AquaSynth's curved staged envelope surface, normalized so operator output level remains a separate authority.
• Retried hard PRC SYNTH1 with the applied-envelope lowering. Latest focused run after fixing the peak picker: log-mel 0.17186502 (was 0.24476814), envelope distance 0.13057204 (was 0.43700194), RMS ratio 1.0000212, zero-crossing ratio 0.7815517, score 0.6501268.
• Listening note resolved: the prior applied-envelope lowering made op2 rise late (0.014 -> 0.613), causing the odd end lilt. The helper now finds the first near-peak before gate, so op2 hits early and decays (0.981 -> 0.843 -> 0.660) like the traced DX7 applied gain.
• Extended staged operator envelopes with per-segment curves: curves=lin,exp,exp,lin. Linear remains the default, and levels can now express deliberate transient overshoot above 1 instead of clipping away the DX7 evidence.
• Added Dx7SysEx.TraceEnvelope, a DX7 EG microscope that follows the internal rate/level state machine closely enough to expose gain and stage over time.
• Added Dx7SysEx.TraceInterpolatedEnvelope, which traces the gain actually applied by Dexed-style operator rendering: one EG sample per 64-sample block, linearly interpolated across the block.
• Added an envelope comparison artifact test that writes artifacts/parity/dx7-envelope-trace/egstep.csv. The first rows show both DX7 raw state and applied gain: raw jumps to 2 immediately, while applied gain ramps from .03125 to 2 over the first 64-sample block and remains near 1 around 20 ms. AquaSynth env=rl is a different contour entirely. The artifact now also includes a curved AquaSynth staged-envelope candidate that tracks the applied-gain contour far more closely.
• Tried adding a first env=dx7 runtime lowering, then cut it. The trace matched the Python graph.py envelope but not Dexed plugin audio, so the syntax was not allowed to survive. The durable result is the microscope and the applied-gain trace, not a half-proven model.

Previous slice:

• Added test-only project-authored Dexed patch rendering through DexedPyRenderer.RenderPatchAsync. It builds a dexed.Patch from explicit operator specs and renders it without adding any shipped fixture or package surface.
• Added an independent project-authored algorithm-8 summed-stack parity test. This backs the topology-aware route lowering outside the public-domain PRC patch, so SummedOperatorModulationRouteIndex is no longer only PRC-shaped evidence.
• Cut the attempted DX7 EG exponential level curve again. On an isolated envelope target, exponential EG levels plus a shorter timing scale improved shape versus linear levels, but PRC still failed log-mel (0.2857573 at a tuned timing scale). The live lowering stays linear for EG levels until an isolated envelope target passes without harming the hard target.

Previous slice:

• Moved the remaining PRC cascaded-route scalar into a topology-aware DX7 route helper. Dx7SysEx.OperatorRouteIndex(topology, edge) now keeps the isolated two-op route scale (6.275) for standalone direct branches and uses the summed/cascaded scale (1.6) for sum edges and direct edges feeding a sum.
• The PRC probe no longer owns any private route-index function. Latest focused run still passes with log-mel 0.24476814, score 0.5708394, RMS ratio 1.0108943.

Previous slice:

• Added the ratio-detune and algorithm-output-compensation rungs to the DX7 lowering. Dx7SysEx.OperatorFrequencyRatio now applies ratio-mode detune from the Dexed/DX7 note formula, and Dx7SysEx.OperatorOutputCompensation maps ROM COM values relative to the algorithm-32 six-output baseline.
• The PRC probe no longer has a carrier-level scale table. It still has a fenced cascaded-route constant (1.6) for the op6/op5/op4 -> op3 stack; that is now named as the next calibration target, not promoted into core lowering.
• Latest PRC run with detune, COM compensation, graph gain .39, and the fenced cascaded-route probe: log-mel 0.24476814, score 0.5708394, RMS ratio 1.0108943, zero-crossing ratio 0.7931764, centroid ratio 1.1131053.

Previous slice:

• Completed the feedback calibration rung. Isolated Dexed feedback sweeps fit a nonlinear AquaSynth feedback table: 0, .01, .02, .05, .10, .19, .38, .66 for DX7 feedback values 0..7.
• Added Dx7SysEx.OperatorFeedbackAmount and moved the PRC feedback lowering off the old voice.Feedback * 0.04 constant. PRC barely changed because feedback value 5 maps to .19, close to the previous accidental .20. The win is ownership: feedback scaling is no longer folklore.

Previous slice:

• Completed the second calibration rung for isolated two-operator FM. A Dexed sweep fits full-scale DX7 modulation at about 12.55 radians. Given the current AquaSynth Faust formula, that maps to an AquaSynth route index of 6.275 for a full-level modulator.
• Added Dx7SysEx.OperatorModulationRouteIndex and a regression test for the calibrated phase-deviation scale. The hard PRC probe applies that scale only to the isolated op2 -> op1 branch; applying it blindly to the cascaded op6/op5/op4 -> op3 stack made PRC worse, which confirms algorithm output compensation is a separate rung.
• Latest PRC run with the carrier curve plus isolated-route calibration: log-mel 0.2526254, score 0.44758993, duration ratio 0.9927914, RMS ratio 0.8931149. The log-mel gate is back to <= 0.255.

Previous slice:

• Wrote docs/dx7-calibration-plan.md and referenced it from memory/spine. The ladder is now: single-carrier amplitude, two-op modulation index, feedback scaling, envelope level curve, algorithm output compensation, then hard PRC replay.
• Completed the first calibration rung. A project-authored Dexed single-carrier output-level sweep fits 2^((outputLevel - 99) / 8) for carrier amplitude. Dx7SysEx.OperatorOutputAmplitude now owns that curve, and ApproximateOperatorLevel uses it instead of the old internal-level proxy.
• Added tests for the measured output-level curve. The hard PRC probe now gates log-mel at <= 0.26 while the next rung calibrates modulation index; latest run after the carrier fix: log-mel 0.2562075, score 0.40430218.
• Calibration lesson: the old operator level helper was not a harmless approximation. It made mid-level operators far too loud and let PRC-specific constants compensate for a broken foundation. Next pressure is route/index scaling for isolated two-operator FM.

Previous slice:

• Reoriented the PRC SYNTH1 hard probe around the perceptual metric that matched listening: log-mel distance. The probe now asserts log-mel <= 0.255 plus a loose aggregate score floor instead of treating aggregate score as the main judge.
• Spectral diagnosis showed the Dexed reference has dominant peaks around 393, 131, 524, and 656 Hz. The prior AquaSynth candidate had too little 80-160 Hz body when based at 392, while the corrected DX7 note basis restored the low body but exposed weak mid harmonic structure and high centroid/zero-crossing mismatch.
• Current run with bundled Python and Faust: log-mel distance 0.25093183, score 0.4135618, envelope distance 0.3595946, duration ratio 0.992578, RMS ratio 1.0658501, zero-crossing ratio 0.24567787, centroid ratio 1.3291793.
• Calibration lesson: the hard target is now a spectral calibration problem. DX7 output/index scaling still needs a real model; aggregate score can move in the wrong direction while log-mel and the ear move in the right direction.

Previous slice:

• Tightened the hard DX7 PRC SYNTH1 probe from a "writes WAVs" smoke test to a modest passing parity target: threshold now requires score >= 0.60.
• The useful cuts were not new syntax. The candidate improved by removing patch soft clipping, setting the graph base frequency to 392, and boosting the op3 carrier branch to compensate the algorithm-8 output/body balance. Global detune and per-edge route damping both made the score worse and were cut.
• Current best run with bundled Python and Faust writes timestamped artifacts under artifacts/parity/dx7-prc-synth1/<run>/: score 0.6057491, log-mel distance 0.27658066, envelope distance 0.38489524, duration ratio 0.98714787, RMS ratio 0.9756519, zero-crossing ratio 1.0458903, centroid ratio 1.093785.

Previous slice:

• Added a hard DX7 PRC SYNTH1 rendered parity probe that writes listening artifacts when dexed-py and Faust are available: artifacts/parity/dx7-prc-synth1/reference-dexed.wav, candidate-aquasynth.wav, candidate.aqua, and report.txt.
• The probe rebuilds analog1.syx voice 17 with readable operator graph syntax and staged env=rl operator envelopes. It asserts a modest hard-target score floor instead of pretending exact DX7 parity is solved.
• Current run with bundled Python and Faust: score 0.4581856, log-mel distance 0.26397973, envelope distance 0.4109424, duration ratio 1.0173812, RMS ratio 0.61393267, zero-crossing ratio 1.1713804, centroid ratio 1.0978767.
• Calibration lesson: shortening the naive DX7 EG timing and lowering the graph base frequency made the candidate much closer. The remaining mismatch is still gain/timbre calibration, not missing env=rl syntax.

Previous slice:

• Added staged operator envelopes for operator graphs: env=rl rates=.004,.12,.2,.4 levels=1,.7,.25,0. This gives the DSL a readable four-stage rate/level contour without infecting the general ADSR voice envelope model.
• Added RateLevelEnvelope to the operator model, parser support for readable and compact env=rl syntax, Faust rl4_env(...) rendering, and a DX7 helper that emits staged envelope script specs from four-rate/four-level operator EG data.
• Verified the surface structurally and through the render path: dotnet test AquaSynth.slnx --no-restore: 53 passed.
• Retried the hard PRC SYNTH1 probe with direct DX7 rate/level lowering. The best quick score was only ~0.316, worse than the hand-tweaked ADSR candidate. The DSL can now express the missing contour shape, but DX7 EG timing/gain calibration remains the next pressure.

Previous slice:

• Added Dx7OperatorLevelApproximation, which distills DX7 operator output level plus key/velocity scaling into a normal AquaSynth level=-style value. This remains DX7 reference-import knowledge, not a generic DSL feature.
• Retried PRC SYNTH1 with effective levels and envelope tweaks. Static level mapping alone did not rescue the hard target: quick probes moved from ~0.24 to ~0.34, and envelope tweaks reached ~0.42. The next missing pressure is DX7-style operator envelope/gain evolution, not just static operator levels.
• Verified with dotnet test AquaSynth.slnx --no-restore: 50 passed.

Previous slice:

• Tried the harder analog1.syx voice 17, PRC SYNTH1 (algorithm 8). The initial routed AquaSynth candidate scored badly (~0.23), which exposed a real missing invariant rather than a threshold-tuning problem.
• Reworked operator feedback emission from a cyclic smoothed self-reference to a renderable Faust feedback expression using delayed recursion. Added FaustCompilerRendersOperatorFeedbackWhenInstalled.
• Exact DX7 feedback scaling and EG behavior are still not solved, but feedback no longer makes the Faust render path fall over.
• Verified with dotnet test AquaSynth.slnx --no-restore: 49 passed.

Previous slice:

• Added the first thresholded DX7 rendered-audio parity rebuild: BuiltInScripts.Dx7StylePublicDomainMcMm53 maps public-domain analog1.syx voice 13, MC-MM 5-3, to a terse AquaSynth sine patch.
• Added PublicDomainDx7McMm53MeetsFirstRenderedParityThresholdWhenInstalled, which renders the DX7 reference through dexed-py, renders the AquaSynth candidate through Faust-generated C#, and asserts score, log-mel distance, envelope distance, duration/RMS ratios, zero-crossing ratio, and centroid ratio.
• This is behavioral parity for a simple sine-like rendered voice, not exact DX7 operator execution. The next DX7 pressure should be a harder voice that audibly needs the operator graph.
• Verified with bundled Python plus dexed-py: parity test passed.
• Verified with dotnet test AquaSynth.slnx --no-restore: 48 passed.

Previous slice:

• Added a public-domain DX7 SysEx fixture from Musical Artifacts artifact 152: tests/AquaSynth.Dsl.Tests/Fixtures/Dx7/PublicDomain/analog1.syx, with provenance and SHA-256 recorded beside it.
• Added a test-only dexed-py reference renderer. It uses AQUASYNTH_DX7_PYTHON when set, otherwise probes py, python, and python3; if dexed-py is absent, the render test returns without turning optional tooling into a hard dependency.
• Added a .nupkg boundary test that packs AquaSynth.Dsl and asserts test fixtures, SysEx banks, and Python helpers are not shipped.
• Verified with bundled Python plus dexed-py: the DX7 fixture renders through Dexed successfully.
• Verified with dotnet test AquaSynth.slnx --no-restore: 47 passed.

Previous slice:

• Added FaustCompiler.RenderAsync, which compiles AquaSynth Faust output to Faust-generated C#, runs it in a temp .NET project, and returns a mono float sample buffer for analysis.
• Added a render test that proves a generated AquaSynth patch produces non-silent audio and can be compared through AudioAnalyzer.
• DX7 audio parity is still not claimed: the candidate renderer exists, but the reference side needs Dexed output or a captured licensed fixture.
• Verified with dotnet test AquaSynth.slnx --no-restore: 44 passed.

Previous slice:

• Added Dx7EnvelopeApproximation, which lowers a DX7 four-rate/four-level EG to a labeled AquaSynth ADSR approximation plus gate duration.
• Reference rebuilds now record operator_envelope_approximation as matched pressure and operator_envelope_exactness as still missing.
• Doctrine now states that DX7 EG approximation is not exact DX7 envelope execution.
• Verified with dotnet test AquaSynth.slnx --no-restore: 43 passed.

Previous slice:

• Added field-site parameter binding for readable operator graph authoring: graph gain/note fields, operator ratio/level/feedback/envelope fields, and route index fields now accept @/param.
• Operator graph Faust emission now substitutes bound parameter expressions at the exact /opgraphs/... field paths.
• Fixed AD operator envelope binding to use /env/decay for the second AD value, matching the ADSR model instead of calling it release by accident.
• Verified with dotnet test AquaSynth.slnx --no-restore: 42 passed.

Previous slice:

• Added a patch-level Playback contract for OneShot, Mono, and Poly playback with Faust MIDI polyphony settings.
• instrument midi=true polyphony=8 now lowers to Faust's standard [midi:on][nvoices:8] option and freq, gain, gate controls.
• Host/MIDI playback no longer emits per-voice /voices/0/note/frequency and /voices/0/note/gate controls; Faust architecture owns allocation.
• Verified with dotnet test AquaSynth.slnx --no-restore: 41 passed.

Previous slice:

• Split note timing from envelope shape. Note now owns frequency, one-shot gate duration, and host/MIDI source; Envelope now owns ADSR shape: attack, decay, sustain level, and release.
• SFXR sustain duration now maps to Note.GateSeconds; SFXR punch maps to a lower ADSR sustain level plus voice gain compensation during import/legacy parsing.
• Added host note mode for MIDI-oriented patches through stable note frequency and note gate controls in generated Faust.
• Moved built-in authoring examples off punch= and onto sustain_level=.
• Verified with dotnet test AquaSynth.slnx --no-restore: 40 passed.

Previous slice:

• Replaced the DX7 algorithm-8 authoring surface with readable operator graph syntax: operator, route, and carrier declarations.
• Added env=ad:attack:decay and env=adsr:attack:decay:sustain:release envelope forms for operator declarations.
• Kept compact ops=/edges= syntax as parser/interchange scaffolding, but it is no longer the built-in authoring example.
• Verified with dotnet test AquaSynth.slnx --no-restore: 36 passed.

Previous slice:

• Added a first-class OperatorGraph model with operators, modulation edges, carriers, graph gain, and operator feedback.
• Added opgraph patch-script syntax. Example: opgraph name=core freq=330 carriers=1,3 ops=6:4:.9,5:3:.8,4:2:.7:.18,3:2:.6,2:1:.75,1:1:.82 edges=6>5:1.1,5>3:.9,4>3:.75,2>1:.85
• Faust emission now mixes operator graphs alongside normal voices.
• Updated the DX7 algorithm-8 rebuild to use a real operator graph for the topology. The remaining missing feature is exact DX7 feedback-register timing and DX7 rate/level envelopes, not graph ownership.
• Verified with dotnet test AquaSynth.slnx --no-restore: 35 passed.

Earlier rebuild slice:

• Added ReferenceRebuild and ReferenceRebuildCatalog for explicit reference-target rebuild attempts.
• Added two DX7-style AquaSynth DSL rebuilds:
  • dx7/algo32-additive-organ: algorithm 32's six-carrier additive shape, which maps cleanly to six AquaSynth voices.
  • dx7/algo8-bright-pair: algorithm 8's two-carrier FM shape, which is only an approximation because the current voice DSL cannot express 6->5, 4+5->3, 2->1, or operator-local self-feedback.
• Added matched/missing feature records so topology mismatch becomes evidence instead of being hidden inside prose.
• Verified with dotnet test AquaSynth.slnx --no-restore: 34 passed.

Earlier topology slice:

• Added DX7 algorithm topology metadata for algorithms 1-32 using Ken Shirriff's reverse-engineered OPS algorithm ROM table.
• Dx7SysEx.AlgorithmTopology now exposes carrier operators, modulation edges, feedback-register writers, direct self-feedback operators, delayed-feedback targets, and raw ROM steps.
• Dx7Voice.Features() now emits carrier_operators, modulation_edge_count, feedback_sources, and self_feedback_operators.
• Representative tests cover algorithm 8, algorithm 16, and algorithm 32.
• Verified with dotnet test AquaSynth.slnx --no-restore: 31 passed.

Earlier slice:

• Added Dx7SysEx records and parsing for DX7 voice edit buffers, packed 128-byte voices, and packed 32-voice SysEx banks.
• Extracted six operators, envelopes, algorithm, feedback, oscillator sync, pitch envelope, LFO, transpose, and voice name into neutral DX7 records.
• Added Dx7Voice.ToReferencePatch and structural feature extraction so DX7 voices can pressure the reference model before translation exists.
• Checksum validation rejects bad wrapped SysEx payloads.
• Verified with dotnet test AquaSynth.slnx --no-restore: 28 passed.

Parameter slice:

• Added explicit PatchParameter contracts: stable path, label, default, min, max, step, unit, automation-rate notes, and notes.
• Added neutral ReferencePatch, ReferenceSource, and ReferenceFeature contracts with provenance/license/hash-ready fields.
• Added param script declarations and duplicate parameter path validation.
• Updated Faust emission so declared parameters produce smoothed hslider controls.
• Implemented Option B parameter binding: numeric fields may reference declared parameters with @/path, for example lpf=@/macro/brightness. The parser records an exact field binding such as /voices/0/filter/lpf and keeps the parameter default as the graph value.
• Faust emission substitutes the parameter expression only at the bound field site. Unbound parameters still emit a warning.
• Verified with dotnet test AquaSynth.slnx --no-restore: 23 passed.

Next likely slice:

• Refine operator graphs with parameter bindings inside graph fields and decide how host MIDI note age/retrigger semantics should be represented beyond the current frequency/gate controls.
• Keep tests focused on structure first, then add rendered audio comparison once the render path is explicit.