Add tract motion and obstruction history

docs/pink-trombone-dsl-parity-plan.md

@@ -70,7 +70,13 @@ named failure against Pink Trombone, but it does not own the anatomy:
      consume `tract_shape` reflection coefficients and boundary reflections.
      True substep execution remains missing.
 
-6. PT parity harness.
+6. `tract_motion`: control-rate slew and obstruction history.
+   - Owns diameter/constriction/velum slew rates and obstruction threshold.
+   - Feeds smoothed target controls and release-transient detection.
+   - Implemented as `tract_motion`; waveguide lowering uses it for control
+     slew and stateful obstruction-opening burst pressure.
+
+7. PT parity harness.
    - Renders fixed PT references for vowels, nasals, fricatives, closures, and
      moving tongue/constriction gestures.
    - Renders Aqua DSL reconstructions.
@@ -79,7 +85,7 @@ named failure against Pink Trombone, but it does not own the anatomy:
 ## First Cut
 
 Implemented owners: `tract_shape`, `glottis`, `tract_injection`,
-`nasal_branch`, and first-pass `propagation=waveguide`.
+`nasal_branch`, `tract_motion`, and first-pass `propagation=waveguide`.
 `tract_shape` owns section diameter/area fields and reflection derivation.
 `glottis` owns excitation quality. `tract_injection` owns positioned
 frication/burst pressure. The current Faust proxy consumes these primitives
@@ -88,10 +94,10 @@ pressure instead of silently inventing all of them inside one helper. The
 waveguide lowering consumes the derived oral reflection field as right/left
 section state equations.
 
-The next cut is cell-local events and timing: the oral/nasal tube now consumes
-the full reflection coefficient fields and distributes frication into section
-updates, but PT's two tract steps per output sample, target diameter slew, and
-obstruction-state transients still need low-level owners.
+The next cut is timing and proof: the oral/nasal tube now consumes the full
+reflection coefficient fields, distributes frication into section updates, and
+derives release bursts from obstruction history. PT's two tract steps per
+output sample and rendered parity fixtures still need low-level owners.
 
 ## Cut Line
 

docs/pink-trombone-parity.md

@@ -57,6 +57,7 @@ Current AquaSynth can express:
 - reusable `tract_injection` declarations for positioned frication/burst
   pressure;
 - reusable `nasal_branch` declarations with velum-controlled junctions;
+- reusable `tract_motion` declarations for slew and obstruction thresholds;
 - a `tract` voice command owned by `Voice.Tract`;
 - Pink Trombone-shaped controls for intensity, tenseness, tongue body,
   constriction, velum/nasal opening, turbulence, lip opening, and end
@@ -74,9 +75,8 @@ Current AquaSynth can express:
 
 Current AquaSynth cannot exactly express:
 
-- per-section diameter targets as synthesis authority;
+- per-section dynamic diameter target arrays;
 - a subgraph that steps twice per output sample;
-- obstruction-state release transients derived from prior closure state;
 - exact Pink Trombone LF glottal coefficient updates.
 
 ## Current Parity Rung
@@ -101,6 +101,8 @@ Trombone anatomy:
   oral/nasal scattering junction when used by a waveguide tract.
 - `tract_injection` pressure is distributed into waveguide section updates by
   position and width when waveguide propagation is active.
+- `tract_motion` smooths tract controls and lets the waveguide derive burst
+  pressure from obstruction history.
 - The proxy script parses and emits Faust with live controls, but its missing
   features explicitly name the waveguide authorities AquaSynth does not own.
 - `tools/vocal-tract-playground` exposes the same control surface for fast

src/AquaSynth.Core/BuiltInScripts.cs

@@ -654,11 +654,20 @@ public static class BuiltInScripts
             loss=0.999
             diameters=0.01,0.35,0.5,0.65,0.8,0.95,1.1,1.25,1.4,1.55,1.7,1.8,1.9,1.9,1.85,1.75,1.65,1.55,1.45,1.35,1.25,1.15,1.05,0.95,0.85,0.75,0.65,0.55
 
+        tract_motion
+            name=pt_motion
+            diameter_slew=18
+            shape_return=8
+            constriction_slew=24
+            velum_slew=16
+            obstruction_threshold=0.05
+
         tract
             shape=pt_human
             glottis=pt_glottis
             injection=pt_constriction
             nasal_branch=pt_nose
+            motion=pt_motion
             propagation=waveguide
             waveguide_loss=0.999
             substeps=2

src/AquaSynth.Core/FaustExport.cs

@@ -37,6 +37,7 @@ public static class FaustEmitter
         }
         source.AppendLine("clip01(x) = min(1.0, max(0.0, x));");
         source.AppendLine("wrap01(x) = x - floor(x);");
+        source.AppendLine("slew(rate,x) = x : *(1.0 - exp(-max(0.0001, rate) / ma.SR)) : + ~ *(exp(-max(0.0001, rate) / ma.SR));");
         source.AppendLine("softclip(x) = ma.tanh(x * 1.35);");
         source.AppendLine("fold(x) = 2.0 * abs(2.0 * (x / 4.0 - floor(x / 4.0)) - 1.0) - 1.0;");
         source.AppendLine("release_start(a,d,g) = max(g, a + d);");
@@ -395,11 +396,21 @@ public static class FaustEmitter
         var hasNose = tract.NoseSections > 0;
         var intensity = $"clip01({parameters.Expression(OwnerField(tractPath, "intensity"), tract.Intensity)})";
         var tenseness = $"clip01({parameters.Expression(OwnerField(tractPath, "tenseness"), tract.Tenseness)})";
-        var tongueIndex = parameters.Expression(OwnerField(tractPath, "tongue_index"), tract.TongueIndex);
-        var tongueDiameter = parameters.Expression(OwnerField(tractPath, "tongue_diameter"), tract.TongueDiameter);
-        var velum = $"clip01(({parameters.Expression(OwnerField(tractPath, "velum"), tract.Velum)} - 0.01) / 0.39)";
-        var constrictionIndex = parameters.Expression(OwnerField(tractPath, "constriction_index"), tract.ConstrictionIndex);
-        var constrictionDiameter = parameters.Expression(OwnerField(tractPath, "constriction_diameter"), tract.ConstrictionDiameter);
+        var motion = tract.Motion;
+        var diameterSlew = parameters.Expression(OwnerField(tractPath, "motion/diameter_slew"), motion?.DiameterSlewPerSecond ?? 18);
+        var constrictionSlew = parameters.Expression(OwnerField(tractPath, "motion/constriction_slew"), motion?.ConstrictionSlewPerSecond ?? 24);
+        var velumSlew = parameters.Expression(OwnerField(tractPath, "motion/velum_slew"), motion?.VelumSlewPerSecond ?? 16);
+        var obstructionThreshold = parameters.Expression(OwnerField(tractPath, "motion/obstruction_threshold"), motion?.ObstructionThreshold ?? 0.05f);
+        var tongueIndexRaw = parameters.Expression(OwnerField(tractPath, "tongue_index"), tract.TongueIndex);
+        var tongueDiameterRaw = parameters.Expression(OwnerField(tractPath, "tongue_diameter"), tract.TongueDiameter);
+        var velumRaw = $"clip01(({parameters.Expression(OwnerField(tractPath, "velum"), tract.Velum)} - 0.01) / 0.39)";
+        var constrictionIndexRaw = parameters.Expression(OwnerField(tractPath, "constriction_index"), tract.ConstrictionIndex);
+        var constrictionDiameterRaw = parameters.Expression(OwnerField(tractPath, "constriction_diameter"), tract.ConstrictionDiameter);
+        var tongueIndex = motion is null ? tongueIndexRaw : $"slew({diameterSlew}, {tongueIndexRaw})";
+        var tongueDiameter = motion is null ? tongueDiameterRaw : $"slew({diameterSlew}, {tongueDiameterRaw})";
+        var velum = motion is null ? velumRaw : $"slew({velumSlew}, {velumRaw})";
+        var constrictionIndex = motion is null ? constrictionIndexRaw : $"slew({constrictionSlew}, {constrictionIndexRaw})";
+        var constrictionDiameter = motion is null ? constrictionDiameterRaw : $"slew({constrictionSlew}, {constrictionDiameterRaw})";
         var turbulence = $"clip01({parameters.Expression(OwnerField(tractPath, "turbulence"), tract.Turbulence)})";
         var lipOpening = parameters.Expression(OwnerField(tractPath, "lip_opening"), tract.LipOpening);
         var glottalReflection = parameters.Expression(OwnerField(tractPath, "glottal_reflection"), tract.GlottalReflection);
@@ -414,8 +425,10 @@ public static class FaustEmitter
         var reflectionEnergy = F(areaFunction is null ? 0.12f : MathF.Min(1, areaFunction.ReflectionCoefficients.Sum(reflection => MathF.Abs(reflection)) / Math.Max(1, areaFunction.ReflectionCoefficients.Count)));
         var aspiration = $"clip01({parameters.Expression(OwnerField(tractPath, "glottis/aspiration"), glottis?.Aspiration ?? 0.08f)})";
         var glottalSkew = $"clip01({parameters.Expression(OwnerField(tractPath, "glottis/skew"), glottis?.Skew ?? 0.42f)})";
-        var injectionPosition = parameters.Expression(OwnerField(tractPath, "injection/position"), injection?.Position ?? tract.ConstrictionIndex);
-        var injectionDiameter = parameters.Expression(OwnerField(tractPath, "injection/diameter"), injection?.Diameter ?? tract.ConstrictionDiameter);
+        var injectionPositionRaw = parameters.Expression(OwnerField(tractPath, "injection/position"), injection?.Position ?? tract.ConstrictionIndex);
+        var injectionDiameterRaw = parameters.Expression(OwnerField(tractPath, "injection/diameter"), injection?.Diameter ?? tract.ConstrictionDiameter);
+        var injectionPosition = motion is null ? injectionPositionRaw : $"slew({constrictionSlew}, {injectionPositionRaw})";
+        var injectionDiameter = motion is null ? injectionDiameterRaw : $"slew({constrictionSlew}, {injectionDiameterRaw})";
         var injectionTurbulence = $"clip01({parameters.Expression(OwnerField(tractPath, "injection/turbulence"), injection?.Turbulence ?? tract.Turbulence)})";
         var injectionBurst = $"clip01({parameters.Expression(OwnerField(tractPath, "injection/burst"), injection?.Burst ?? 0)})";
         var injectionWidth = $"max(0.05, {parameters.Expression(OwnerField(tractPath, "injection/width"), injection?.Width ?? 1)})";
@@ -441,7 +454,12 @@ public static class FaustEmitter
         source.AppendLine($"{name}_tract_lf = ({name}_tract_lf_open - (0.12 + {tenseness} * 0.62) * sin(4.0 * ma.PI * {name}_tract_phase)) * {intensity} * (0.45 + 0.75 * pow(max(0.0, {tenseness}), 0.35));");
         source.AppendLine($"{name}_tract_aspiration = no.noise * {intensity} * {aspiration} * (1.0 - sqrt(max(0.0, {tenseness}))) * (0.08 + 0.22 * {name}_tract_constriction_close);");
         source.AppendLine($"{name}_tract_frication = no.noise * max({turbulence} * {name}_tract_constriction_close, {injectionTurbulence} * {name}_tract_injection_close) * {intensity} * (0.25 + 0.75 * {name}_tract_injection_pos) * (0.2 + 0.8 * {tenseness});");
-        source.AppendLine($"{name}_tract_burst = no.noise * max({name}_tract_constriction_close * 0.18, {name}_tract_injection_close * {injectionBurst}) * exp(-age * (45.0 + max({name}_tract_constriction_close, {name}_tract_injection_close) * 120.0));");
+        source.AppendLine($"{name}_tract_prev_injection_close = {name}_tract_injection_close : mem;");
+        source.AppendLine($"{name}_tract_obstructed = select2({injectionDiameter} < {obstructionThreshold}, 0.0, 1.0);");
+        source.AppendLine($"{name}_tract_prev_obstructed = {name}_tract_obstructed : mem;");
+        source.AppendLine($"{name}_tract_release_opening = max(0.0, {name}_tract_prev_injection_close - {name}_tract_injection_close) * {name}_tract_prev_obstructed;");
+        source.AppendLine($"{name}_tract_release_memory = {name}_tract_release_opening : + ~ *(0.935);");
+        source.AppendLine($"{name}_tract_burst = no.noise * {name}_tract_release_memory * {injectionBurst} * {intensity};");
         source.AppendLine($"{name}_tract_excitation = ({name}_tract_lf + {name}_tract_aspiration + {name}_tract_burst) * (0.55 + 0.45 * abs({glottalReflection}));");
         source.AppendLine($"{name}_tract_injection_pressure = {name}_tract_frication * (0.55 + 0.45 * abs({glottalReflection}));");
         source.AppendLine($"{name}_tract_raw = {name}_tract_excitation + {name}_tract_injection_pressure;");

src/AquaSynth.Core/Model.cs

@@ -213,6 +213,14 @@ public sealed record NasalBranch(
     float Reflection = -0.85f,
     float Loss = 0.999f);
 
+public sealed record TractMotion(
+    string Name = "",
+    float DiameterSlewPerSecond = 18,
+    float ShapeReturnPerSecond = 8,
+    float ConstrictionSlewPerSecond = 24,
+    float VelumSlewPerSecond = 16,
+    float ObstructionThreshold = 0.05f);
+
 public sealed record Modulator(
     ModTarget Target,
     ModWaveform Waveform = ModWaveform.Sine,
@@ -271,6 +279,7 @@ public sealed record VocalTract(
     GlottalSource? Glottis = null,
     TractInjection? Injection = null,
     NasalBranch? Nasal = null,
+    TractMotion? Motion = null,
     TractPropagationMode Propagation = TractPropagationMode.Resonator,
     float WaveguideLoss = 0.999f,
     int Substeps = 1);
@@ -450,6 +459,7 @@ public sealed record SynthPatch
     public IReadOnlyList<GlottalSource> GlottalSources { get; init; } = Array.Empty<GlottalSource>();
     public IReadOnlyList<TractInjection> TractInjections { get; init; } = Array.Empty<TractInjection>();
     public IReadOnlyList<NasalBranch> NasalBranches { get; init; } = Array.Empty<NasalBranch>();
+    public IReadOnlyList<TractMotion> TractMotions { get; init; } = Array.Empty<TractMotion>();
     public IReadOnlyList<OperatorGraph> OperatorGraphs { get; init; } = Array.Empty<OperatorGraph>();
     public IReadOnlyList<ControlLane> Controls { get; init; } = Array.Empty<ControlLane>();
     public IReadOnlyList<PatchParameter> Parameters { get; init; } = Array.Empty<PatchParameter>();

src/AquaSynth.Core/PatchScript.cs

@@ -44,6 +44,8 @@ public static class PatchScript
         private readonly Dictionary<string, TractInjection> _tractInjectionsByName = new(StringComparer.OrdinalIgnoreCase);
         private readonly List<NasalBranch> _nasalBranches = [];
         private readonly Dictionary<string, NasalBranch> _nasalBranchesByName = new(StringComparer.OrdinalIgnoreCase);
+        private readonly List<TractMotion> _tractMotions = [];
+        private readonly Dictionary<string, TractMotion> _tractMotionsByName = new(StringComparer.OrdinalIgnoreCase);
         private readonly Dictionary<string, string> _defaults = new(StringComparer.OrdinalIgnoreCase);
         private readonly Dictionary<string, Dictionary<string, string>> _layerDefaults = new(StringComparer.OrdinalIgnoreCase);
         private PendingOperatorGraph? _pendingOperatorGraph;
@@ -69,6 +71,7 @@ public static class PatchScript
                 GlottalSources = _glottalSources,
                 TractInjections = _tractInjections,
                 NasalBranches = _nasalBranches,
+                TractMotions = _tractMotions,
                 OperatorGraphs = _operatorGraphs,
                 Controls = _controls,
                 Parameters = _parameters,
@@ -136,6 +139,10 @@ public static class PatchScript
                     FlushPendingOperatorGraph();
                     AddNasalBranch(fields, line);
                     break;
+                case "tract_motion":
+                    FlushPendingOperatorGraph();
+                    AddTractMotion(fields, line);
+                    break;
                 case "voice":
                     FlushPendingOperatorGraph();
                     Voices.Add(ParseVoice(ExpandVoiceFields(fields, line), VoicePath(Voices.Count), line));
@@ -364,6 +371,25 @@ public static class PatchScript
             _nasalBranchesByName[name] = branch;
         }
 
+        private void AddTractMotion(IReadOnlyDictionary<string, string> fields, int line)
+        {
+            var name = Required(fields, "name", line);
+            if (_tractMotionsByName.ContainsKey(name))
+            {
+                throw new PatchScriptException(line, $"duplicate tract motion `{name}`");
+            }
+
+            var motion = new TractMotion(
+                name,
+                GetBoundFloat(fields, line, 18, $"/tract_motions/{_tractMotions.Count}/diameter_slew", "diameter_slew", "slew"),
+                GetBoundFloat(fields, line, 8, $"/tract_motions/{_tractMotions.Count}/shape_return", "shape_return", "return_slew"),
+                GetBoundFloat(fields, line, 24, $"/tract_motions/{_tractMotions.Count}/constriction_slew", "constriction_slew", "constriction"),
+                GetBoundFloat(fields, line, 16, $"/tract_motions/{_tractMotions.Count}/velum_slew", "velum_slew", "velum"),
+                GetBoundFloat(fields, line, 0.05f, $"/tract_motions/{_tractMotions.Count}/obstruction_threshold", "obstruction_threshold", "closure"));
+            _tractMotions.Add(motion);
+            _tractMotionsByName[name] = motion;
+        }
+
         private Dictionary<string, string> ExpandVoiceFields(Dictionary<string, string> fields, int line)
         {
             var expanded = new Dictionary<string, string>(_defaults, StringComparer.OrdinalIgnoreCase);
@@ -608,6 +634,7 @@ public static class PatchScript
             var glottis = ParseGlottalSourceReference(fields, ownerPath, line);
             var injection = ParseTractInjectionReference(fields, ownerPath, line);
             var nasal = ParseNasalBranchReference(fields, ownerPath, line);
+            var motion = ParseTractMotionReference(fields, ownerPath, line);
             var sections = GetBoundInt(fields, line, areaFunction?.Sections ?? 44, OwnerField(ownerPath, "tract/sections"), "sections", "cells");
             if (sections < 4)
             {
@@ -643,6 +670,7 @@ public static class PatchScript
                     glottis,
                     injection,
                     nasal,
+                    motion,
                     ParseTractPropagationMode(GetAny(fields, ["propagation", "model"], "resonator"), line),
                     GetBoundFloat(fields, line, 0.999f, OwnerField(ownerPath, "tract/waveguide_loss"), "waveguide_loss", "loss"),
                     GetBoundInt(fields, line, 1, OwnerField(ownerPath, "tract/substeps"), "substeps", "steps"))
@@ -1136,6 +1164,30 @@ public static class PatchScript
                 GetBoundFloat(fields, line, fallback.Loss, OwnerField(ownerPath, "tract/nasal/loss"), "nose_loss"));
         }
 
+        private TractMotion? ParseTractMotionReference(IReadOnlyDictionary<string, string> fields, string ownerPath, int line)
+        {
+            var hasInlineMotion = HasAny(fields, "diameter_slew", "shape_return", "constriction_slew", "velum_slew", "obstruction_threshold");
+            var hasNamedMotion = TryGetAny(fields, ["motion", "tract_motion"], out var motionName);
+            if (!hasNamedMotion && !hasInlineMotion)
+            {
+                return null;
+            }
+            TractMotion? namedMotion = null;
+            if (hasNamedMotion && !_tractMotionsByName.TryGetValue(motionName, out namedMotion))
+            {
+                throw new PatchScriptException(line, $"unknown tract motion `{motionName}`");
+            }
+
+            var fallback = hasNamedMotion ? namedMotion! : new TractMotion();
+            return new TractMotion(
+                hasNamedMotion ? motionName : "",
+                GetBoundFloat(fields, line, fallback.DiameterSlewPerSecond, OwnerField(ownerPath, "tract/motion/diameter_slew"), "diameter_slew", "slew"),
+                GetBoundFloat(fields, line, fallback.ShapeReturnPerSecond, OwnerField(ownerPath, "tract/motion/shape_return"), "shape_return", "return_slew"),
+                GetBoundFloat(fields, line, fallback.ConstrictionSlewPerSecond, OwnerField(ownerPath, "tract/motion/constriction_slew"), "constriction_slew"),
+                GetBoundFloat(fields, line, fallback.VelumSlewPerSecond, OwnerField(ownerPath, "tract/motion/velum_slew"), "velum_slew"),
+                GetBoundFloat(fields, line, fallback.ObstructionThreshold, OwnerField(ownerPath, "tract/motion/obstruction_threshold"), "obstruction_threshold", "closure"));
+        }
+
         private static TractAreaFunction ParseTractAreaFunction(IReadOnlyDictionary<string, string> fields, int line)
         {
             var hasDiameters = TryGetAny(fields, ["diameters", "diameter"], out var diametersText);
@@ -1576,6 +1628,7 @@ public static class PatchScript
         "glottis" or "glottal" or "excitation" => "glottis",
         "tract_injection" or "injection" or "frication" or "burst" => "tract_injection",
         "nasal_branch" or "nose_branch" or "nasal" => "nasal_branch",
+        "tract_motion" or "shape_motion" or "slew" => "tract_motion",
         "v" or "voice" => "voice",
         "tract" or "vt" or "tractvoice" or "tract_voice" => "tract",
         "opgraph" or "ops" or "operators" => "opgraph",

src/AquaSynth.Core/PinkTromboneReference.cs

@@ -70,6 +70,8 @@ public static class PinkTromboneReference
                 new("nose_waveguide_cells", "nasal_branch", "AquaSynth can author a nasal branch as its own diameter/area tube."),
                 new("nose_junction", "generated three-way junction", "Waveguide lowering can emit a velum-controlled oral/nasal junction from local areas."),
                 new("positioned_turbulence_applied_to_waveguide_cells", "position-weighted waveguide injection", "Frication pressure can be distributed into oral waveguide section updates by injection position and width."),
+                new("tract_shape_motion", "tract_motion slew semantics", "AquaSynth can author tract control slew and obstruction thresholds for moving diameter targets."),
+                new("closure_transients", "obstruction-history burst", "Waveguide lowering derives burst pressure from prior obstruction state and current opening."),
                 new("runtime_controls", "/pink/frequency,/pink/intensity,/pink/tenseness,/pink/tongue/index,/pink/tongue/diameter,/pink/velum,/pink/turbulence", "AquaSynth can expose stable runtime parameter paths."),
                 new("glottal_pitch_pressure_proxy", "tract LF-style source", "AquaSynth can drive pitch/loudness-like controls without recompiling."),
                 new("turbulence_proxy", "position-aware frication controls", "The tract voice has constriction index/diameter and turbulence controls."),
@@ -77,7 +79,6 @@ public static class PinkTromboneReference
             ],
             [
                 new("twice_rate_tract_stepping", "two tract steps per audio sample", "AquaSynth voice graphs do not express a subgraph with its own stepping rate."),
-                new("stateful_closure_release_transients", "obstruction release impulse", "AquaSynth can author burst pressure, but it does not yet observe prior obstruction state and emit PT-style release transients."),
                 new("lf_glottal_exactness", "Pink Trombone LF-style coefficients", "The proxy uses ordinary oscillators/noise, not the LF coefficient path from tenseness.")
             ],
             "This is a deliberately non-passing rebuild: it keeps the current source-filter proxy parseable while naming the tract-DSP authority AquaSynth lacks.");

state/evidence.jsonl

@@ -134,3 +134,4 @@
 {"date":"2026-05-25","topic":"pink-trombone-expressive-parity","lesson":"The Pink Trombone path is expressive-parity first, audio-parity second. Do not half-consume PT into one helper. Decompose its pipeline into reusable Aqua DSL primitives, then golf rendered PT fixtures with log-mel cosine similarity once the language can express the pipeline honestly.","evidence":"Added `docs/pink-trombone-dsl-parity-plan.md`, oriented parity docs/spine/map, and implemented the first primitive: `tract_shape` declarations parse into reusable `TractAreaFunction` objects that derive areas/reflection coefficients and feed `Voice.Tract` lowering. Focused tests assert shape ownership, coefficient derivation, and reference matched/missing features."}
 {"date":"2026-05-26","topic":"pink-trombone-low-level-dsp-primitives","lesson":"PT parity must be targeted at the low-level DSP loop: right/left traveling-wave state, reflection coefficients, scattering junctions, nasal branch junctions, and injected excitation. AquaSynth now has reusable primitives for tract shape, glottal source, tract injection, nasal branch, and generated oral/nasal waveguide lowering; remaining gaps are true twice-rate stepping, cell-local turbulence/transient injection, target diameter slew, and rendered PT fixture scoring.","evidence":"Added `GlottalSource`, `TractInjection`, `NasalBranch`, `TractPropagationMode.Waveguide`, parser commands `glottis`, `tract_injection`, `nasal_branch`, and Faust generation for oral right/left waveguide sections plus a velum-controlled three-way nose junction. Focused verification: `dotnet build tests\\AquaSynth.Dsl.Tests\\AquaSynth.Dsl.Tests.csproj --no-restore --disable-build-servers -v minimal` and focused `dotnet test --no-build` passed."}
 {"date":"2026-05-26","topic":"waveguide-cell-injection","lesson":"A positioned injection primitive is not enough; frication has to enter the traveling-wave section updates. AquaSynth waveguide lowering now computes a section-space injection cell and distributes injection pressure across oral waveguide right/left updates by position and width. Remaining PT DSP gaps are true substep execution, obstruction-history transients, diameter target slew, and rendered parity fixtures.","evidence":"Changed Faust waveguide lowering to split glottal excitation from tract injection pressure, emit `wg_injection_cell` and `wg_inject_N` terms, and add those terms to oral waveguide section and nasal-junction updates. Verification required disabling build servers/shared compilation/parallel build after normal dotnet builds hung: `dotnet build tests\\AquaSynth.Dsl.Tests\\AquaSynth.Dsl.Tests.csproj --no-restore --disable-build-servers -p:UseSharedCompilation=false -p:BuildInParallel=false -v minimal`; focused `dotnet test --no-build` passed 3 tests."}
+{"date":"2026-05-26","topic":"tract-motion-obstruction-history","lesson":"PT-style movement and release bursts are temporal DSP semantics, not preset flavor. AquaSynth now has `tract_motion` to own slew rates and obstruction threshold; waveguide lowering smooths tract controls and derives burst pressure from previous obstruction state opening into current non-obstruction. Remaining PT expression gaps are true two-steps-per-sample execution, dynamic per-section target diameter arrays, and rendered parity fixtures.","evidence":"Added `TractMotion`, parser command `tract_motion`, voice references/inline overrides, Faust `slew(rate,x)`, smoothed tongue/constriction/velum controls, `tract_prev_injection_close`, `tract_obstructed`, and `tract_release_memory` burst generation. Verification: no-hang build/test command with `--disable-build-servers -p:UseSharedCompilation=false -p:BuildInParallel=false`; focused tests passed 3."}

state/spine.yaml

@@ -112,7 +112,7 @@ live_invariants:
   - The speech lane is the active center: IPA parity, utterance embeddings, synth-driver automation, rendered loss, and compiled Faust control sweeps take priority over new DX7/Zyn digestion.
   - Every learned speech arrow must stay inspectable: utterance metadata -> embedding, embedding plus phonetic features -> automation, automation -> rendered audio, rendered audio -> loss/gradient.
   - Pink Trombone parity is structural waveguide pressure, not permission to add more formant proxy knobs. AquaSynth now has a `tract` DSL command that lowers into `Voice.Tract` with PT-shaped runtime controls and a Faust tract-voice proxy; it is still an ordinary voice treatment, not a separate graph owner and not an exact 44-cell/28-cell bidirectional waveguide.
-  - PT expressive parity should decompose into reusable Aqua primitives before audio golf: `tract_shape` owns section diameters/areas and derived reflection coefficients; `glottis` owns excitation controls; `tract_injection` owns positioned frication/burst controls and now distributes frication pressure into waveguide section updates; `nasal_branch` owns a second diameter/area tube; `propagation=waveguide` lowers tract voices into generated oral/nasal right-left waveguide equations. Remaining low-level PT gaps are true two-steps-per-sample execution, obstruction-history transients, target diameter slew, and parity fixtures.
+  - PT expressive parity should decompose into reusable Aqua primitives before audio golf: `tract_shape` owns section diameters/areas and derived reflection coefficients; `glottis` owns excitation controls; `tract_injection` owns positioned frication/burst controls and now distributes frication pressure into waveguide section updates; `nasal_branch` owns a second diameter/area tube; `tract_motion` owns control slew and obstruction threshold; `propagation=waveguide` lowers tract voices into generated oral/nasal right-left waveguide equations with obstruction-history burst pressure. Remaining low-level PT gaps are true two-steps-per-sample execution, dynamic per-section target diameter arrays, and parity fixtures.
   - If dotnet builds hang in this workspace, stop orphan dotnet workers and retry with `--disable-build-servers -p:UseSharedCompilation=false -p:BuildInParallel=false`; plain parallel/shared builds can stall without useful diagnostics.
   - eSpeak NG is an early parity reference for timing, IPA coverage, and log-mel pressure, not an anatomy oracle or final target.
   - Do not expand into prosody, emotional context, personality, or broad Weksa expressivity until the tiny IPA utterance harness can show useful loss movement.

tests/AquaSynth.Dsl.Tests/PatchScriptTests.cs

@@ -90,7 +90,8 @@ public sealed class PatchScriptTests
             glottis name=modal intensity=.72 tenseness=@/pink/tenseness aspiration=.14 reflection=.72 skew=.5
             tract_injection name=sibilant position=6 diameter=.45 turbulence=.8 burst=.3 width=.8
             nasal_branch name=nose junction=3 velum=.2 diameters=.01,.6,1.2,1.4
-            tract shape=human glottis=modal injection=sibilant nasal_branch=nose propagation=waveguide waveguide_loss=.998 substeps=2 freq=140 tongue_index=4 tongue_diameter=1.4 velum=.2
+            tract_motion name=quick diameter_slew=20 constriction_slew=30 velum_slew=12 obstruction_threshold=.08
+            tract shape=human glottis=modal injection=sibilant nasal_branch=nose motion=quick propagation=waveguide waveguide_loss=.998 substeps=2 freq=140 tongue_index=4 tongue_diameter=1.4 velum=.2
             """);
 
         var shape = Assert.Single(patch.TractShapes);
@@ -107,6 +108,9 @@ public sealed class PatchScriptTests
         var nasal = Assert.Single(patch.NasalBranches);
         Assert.Equal("nose", nasal.Name);
         Assert.Equal(4, nasal.AreaFunction?.Sections);
+        var motion = Assert.Single(patch.TractMotions);
+        Assert.Equal("quick", motion.Name);
+        Assert.Equal(.08f, motion.ObstructionThreshold, 5);
 
         var voice = Assert.Single(patch.Voices);
         Assert.NotNull(voice.Tract);
@@ -118,6 +122,7 @@ public sealed class PatchScriptTests
         Assert.Equal(glottis, voice.Tract.Glottis);
         Assert.Equal(injection, voice.Tract.Injection);
         Assert.Equal(nasal, voice.Tract.Nasal);
+        Assert.Equal(motion, voice.Tract.Motion);
         Assert.Equal(TractPropagationMode.Waveguide, voice.Tract.Propagation);
         Assert.Equal(.998f, voice.Tract.WaveguideLoss, 5);
         Assert.Equal(2, voice.Tract.Substeps);
@@ -132,6 +137,9 @@ public sealed class PatchScriptTests
         Assert.Contains("tract_injection_close", faust);
         Assert.Contains("wg_injection_cell", faust);
         Assert.Contains("wg_inject_6", faust);
+        Assert.Contains("tract_release_memory", faust);
+        Assert.Contains("tract_obstructed", faust);
+        Assert.Contains("slew(", faust);
         Assert.Contains("wg_scatter_1", faust);
         Assert.Contains("nose_reflect_nose", faust);
         Assert.Contains("tract_nose_waveguide", faust);
@@ -370,10 +378,13 @@ public sealed class PatchScriptTests
         Assert.Contains(rebuild.MatchedFeatures, feature => feature.Name == "nose_waveguide_cells");
         Assert.Contains(rebuild.MatchedFeatures, feature => feature.Name == "nose_junction");
         Assert.Contains(rebuild.MatchedFeatures, feature => feature.Name == "positioned_turbulence_applied_to_waveguide_cells");
+        Assert.Contains(rebuild.MatchedFeatures, feature => feature.Name == "tract_shape_motion");
+        Assert.Contains(rebuild.MatchedFeatures, feature => feature.Name == "closure_transients");
         Assert.NotEmpty(patch.TractShapes);
         Assert.NotEmpty(patch.GlottalSources);
         Assert.NotEmpty(patch.TractInjections);
         Assert.NotEmpty(patch.NasalBranches);
+        Assert.NotEmpty(patch.TractMotions);
         Assert.NotEmpty(patch.Parameters);
         Assert.Contains("process =", export.Source);
     }