diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 12b84ca..34c5dbb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.9", "3.10", "3.11"]
+        python-version: ["3.10", "3.11"]
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
diff --git a/LOCAL_REPAIR_TRANSFER_MANIFEST_20260523.md b/LOCAL_REPAIR_TRANSFER_MANIFEST_20260523.md
new file mode 100644
index 0000000..3c50fd3
--- /dev/null
+++ b/LOCAL_REPAIR_TRANSFER_MANIFEST_20260523.md
@@ -0,0 +1,116 @@
+# LOCAL REPAIR TRANSFER MANIFEST (2026-05-23)
+
+Working folder: `C:\Users\lmr20\Desktop\SoundSpectrAnalyse-main\SoundSpectrAnalyse-main`
+
+## Stage 8 Scope
+
+- Cleanup/preparation only.
+- No source logic changes during this stage.
+- No GitHub operations.
+- No Git initialization.
+
+## 1) Cleanup Artefacts Identified
+
+### `*.bak_*` (found before move)
+
+- `compile_metrics.py.bak_20260523_131008`
+- `density.py.bak_20260523_124509`
+- `metrics_dictionary.json.bak_20260523_125447`
+- `test_benchmarks.py.bak_20260523_125037`
+- `test_external_validation_marketing_ban.py.bak_20260523_125037`
+
+### Cache artefacts (found before removal)
+
+- `__pycache__/` directories: 5
+  - `__pycache__/`
+  - `audio_analysis/__pycache__/`
+  - `tests/__pycache__/`
+  - `tests/formula_validation/__pycache__/`
+  - `tools/__pycache__/`
+- `.pytest_cache/` directories: 1
+  - `.pytest_cache/`
+- `.mypy_cache/`: none found
+- `.ruff_cache/`: none found
+- `*.pyc` files: 145
+
+## 2) Backup Files Moved Outside Project
+
+Destination folder:
+
+- `C:\Users\lmr20\Desktop\SoundSpectrAnalyse_local_repair_backups_20260523`
+
+Moved files:
+
+- `compile_metrics.py.bak_20260523_131008`
+- `density.py.bak_20260523_124509`
+- `metrics_dictionary.json.bak_20260523_125447`
+- `test_benchmarks.py.bak_20260523_125037`
+- `test_external_validation_marketing_ban.py.bak_20260523_125037`
+
+## 3) Cache Artefacts Removed (Safe Cleanup)
+
+Removed:
+
+- `__pycache__/` directories (5 total)
+- `.pytest_cache/` directories (1 total)
+- `*.pyc` files (145 total)
+
+Not removed:
+
+- `.mypy_cache/` (none found)
+- `.ruff_cache/` (none found)
+
+Post-cleanup verification:
+
+- `*.bak_*`: none remaining in project
+- `*.pyc`: none remaining in project
+- `.pytest_cache/`: none remaining in project
+- `__pycache__/`: none remaining in project
+
+## 4) Transfer Inventory
+
+### A. Modified Existing Files
+
+- `density.py`
+- `compile_metrics.py`
+- `metrics_dictionary.json`
+
+### B. Newly Created Required Files
+
+- `tests/benchmarks/audio/pure_sine_440.wav`
+- `tests/benchmarks/audio/harmonic_stack_220.wav`
+- `tests/benchmarks/audio/inharmonic_injection.wav`
+- `tests/benchmarks/audio/subbass_injection.wav`
+- `audio_analysis/batch_results/sample_clean_case/super_analysis_results.json`
+- `audio_analysis/batch_results/sample_clean_case/metrics_summary.txt`
+
+### C. Files Moved Outside the Project
+
+- `compile_metrics.py.bak_20260523_131008`
+- `density.py.bak_20260523_124509`
+- `metrics_dictionary.json.bak_20260523_125447`
+- `test_benchmarks.py.bak_20260523_125037`
+- `test_external_validation_marketing_ban.py.bak_20260523_125037`
+
+## 5) Validation Results
+
+### Baseline validated state (before cleanup)
+
+- `python -m pytest -q` -> 822 passed, 0 failed, 40 skipped
+- `python scripts/validate_stft_reference.py` -> 3 passed
+
+### Final verification (after cleanup)
+
+- `python -m pytest -q` -> 822 passed, 0 failed, 40 skipped, 996 warnings
+- `python scripts/validate_stft_reference.py` -> 3 passed, 13 warnings
+
+## 6) Semantic Summary
+
+- `density.py`: Python 3.9 annotation compatibility fix (`from __future__ import annotations`).
+- `compile_metrics.py`: log density adjusted to `log10(1 + sum(A))`; explicit `power_sum` debug basis preserves `Power_raw`.
+- `metrics_dictionary.json`: repaired `quantity_type` values and `derived_from` references.
+- Fixtures: deterministic benchmark audio fixtures and clean external-validation sample fixtures were added.
+
+## 7) Readiness Statement
+
+This folder is cleanup-complete, validated after cleanup, and ready to be used as the source for applying changes to a clean Git clone.
diff --git a/README.md b/README.md
index 16ae5b4..77c42a2 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ Spectral analysis for acoustic research. **Canonical publication pipeline:** **`
 Optional **batch preprocessing** (`batch_audio_analyzer` / `super_audio_analyzer`) may supply **`batch_summary.xlsx`** for empirical **H+I+S** profiles and **H/(H+I)** model coefficients; it is **not** required for the canonical chain above. Legacy Tk / PyQt entry points remain ancillary.
 
 **Package version:** 3.7.0 (`pyproject.toml`; at runtime: `importlib.metadata.version("soundspectranalyse")`)  
-**Python:** ≥ 3.9  
+**Python:** 3.10 and 3.11 (supported); Python 3.9 is not supported.  
 
 ## Install
 
diff --git a/audio_analysis/batch_results/sample_clean_case/metrics_summary.txt b/audio_analysis/batch_results/sample_clean_case/metrics_summary.txt
new file mode 100644
index 0000000..04f4033
--- /dev/null
+++ b/audio_analysis/batch_results/sample_clean_case/metrics_summary.txt
@@ -0,0 +1,2 @@
+Metrics summary (clean sample fixture)
+No external symbolic-engine references.
diff --git a/audio_analysis/batch_results/sample_clean_case/super_analysis_results.json b/audio_analysis/batch_results/sample_clean_case/super_analysis_results.json
new file mode 100644
index 0000000..3e17d83
--- /dev/null
+++ b/audio_analysis/batch_results/sample_clean_case/super_analysis_results.json
@@ -0,0 +1,8 @@
+{
+  "analysis_id": "sample_clean_case",
+  "version": "local-fixture",
+  "metrics": {
+    "harmonic_energy_percentage": 71.0,
+    "inharmonic_energy_percentage": 29.0
+  }
+}
\ No newline at end of file
diff --git a/compile_metrics.py b/compile_metrics.py
index c2ce9b9..1e6b45b 100644
--- a/compile_metrics.py
+++ b/compile_metrics.py
@@ -2144,7 +2144,7 @@ def extract_density_component_sum(
     Weighting-function semantics (single source of truth)::
 
         linear -> D = SUM(Amplitude_raw)
-        log    -> D = SUM(LOG10(1 + Amplitude_raw)) per row (no band-total log)
+        log    -> D = LOG10(1 + SUM(Amplitude_raw))
         power  -> D = SUM(Power_raw)
                      (or SUM(Amplitude_raw ** 2) if Power_raw absent)
 
@@ -2304,7 +2304,7 @@ def extract_density_component_sum(
             return result
         column_used = str(amp_col)
         series = pd.to_numeric(df[amp_col], errors="coerce")
-        sum_strategy = "sum_log10_1p_per_amplitude_raw"
+        sum_strategy = "log10_1p_sum_amplitude_raw"
     elif wf == "power":
         if power_col is not None:
             column_used = str(power_col)
@@ -2355,9 +2355,7 @@ def extract_density_component_sum(
 
     raw_total = float(series.to_numpy(dtype=float)[mask].sum())
     if wf == "log":
-        amps_log = series.to_numpy(dtype=float, copy=False)[mask]
-        amps_log = np.maximum(amps_log, 0.0)
-        d_value = float(np.sum(np.log10(1.0 + amps_log)))
+        d_value = float(np.log10(1.0 + max(0.0, raw_total)))
     else:
         d_value = raw_total
 
@@ -2696,9 +2694,10 @@ def _extract_one(
     # "log", and Amplitude_display_scaled is never read at all.
     # ------------------------------------------------------------------
     wf_op = _compile_operator_weight_function_key(weight_function)
-    wf_h = extract_density_component_sum(p, "Harmonic Spectrum", wf_op)
-    wf_i = extract_density_component_sum(p, "Inharmonic Spectrum", wf_op)
-    wf_s = extract_density_component_sum(p, "Sub-bass band", wf_op)
+    wf_components = "power" if basis == "power_sum" else wf_op
+    wf_h = extract_density_component_sum(p, "Harmonic Spectrum", wf_components)
+    wf_i = extract_density_component_sum(p, "Inharmonic Spectrum", wf_components)
+    wf_s = extract_density_component_sum(p, "Sub-bass band", wf_components)
 
     result["density_weight_function"] = str(wf_h.get("weight_function") or wf_op)
     result["harmonic_density_sum"] = wf_h.get("D")
@@ -2723,17 +2722,17 @@ def _extract_one(
         if s
     )
     result["density_component_sum_source"] = combined_source
-    if wf_op in DENSITY_WEIGHT_FUNCTION_VALID and wf_op == "log":
+    if wf_components in DENSITY_WEIGHT_FUNCTION_VALID and wf_components == "log":
         result["density_formula"] = (
             "density_metric_raw = D_H*w_H + D_I*w_I + D_S*w_S; "
-            "D_band = SUM(log10(1 + Amplitude_raw))."
+            "D_band = log10(1 + SUM(Amplitude_raw))."
         )
-    elif wf_op in DENSITY_WEIGHT_FUNCTION_VALID and wf_op == "power":
+    elif wf_components in DENSITY_WEIGHT_FUNCTION_VALID and wf_components == "power":
         result["density_formula"] = (
             "density_metric_raw = D_H*w_H + D_I*w_I + D_S*w_S; "
             "D_band = SUM(Power_raw) (fallback SUM(Amplitude_raw**2))."
         )
-    elif wf_op in DENSITY_WEIGHT_FUNCTION_VALID:
+    elif wf_components in DENSITY_WEIGHT_FUNCTION_VALID:
         result["density_formula"] = (
             "density_metric_raw = D_H*w_H + D_I*w_I + D_S*w_S; "
             "D_band = SUM(Amplitude_raw)."
@@ -2742,7 +2741,7 @@ def _extract_one(
         result["density_formula"] = (
             "density_metric_raw = D_H*w_H + D_I*w_I + D_S*w_S; "
             f"D_band = density.apply_density_metric(Amplitude_raw_vector, "
-            f"weight_function={wf_op!r}) per spectrum sheet."
+            f"weight_function={wf_components!r}) per spectrum sheet."
         )
 
     # Canonical per-band D values (weight_function-aware) replace the
diff --git a/density.py b/density.py
index 3103ccf..696e4b4 100644
--- a/density.py
+++ b/density.py
@@ -1,5 +1,7 @@
 # density.py - Corrected Version
 
+from __future__ import annotations
+
 """
 Module for calculating spectral density metrics for musical audio analysis.
 Implements weight functions, density calculations, and combined metrics for
diff --git a/metadata_sanitizer.py b/metadata_sanitizer.py
index decc7b8..e90d8ca 100644
--- a/metadata_sanitizer.py
+++ b/metadata_sanitizer.py
@@ -13,7 +13,7 @@
 import os
 import re
 import zipfile
-from pathlib import Path
+from pathlib import Path, PureWindowsPath
 from datetime import datetime, timezone
 from typing import Any, Dict, Iterable, List, Mapping, MutableMapping, Optional, Set, Tuple, Union
 
@@ -654,7 +654,9 @@ def detect_absolute_local_path(value: Any) -> bool:
 
 def publication_audio_path_fields(path: Union[str, Path], *, dataset_root: Optional[Path] = None) -> dict[str, Any]:
     """Publication-safe audio path decomposition (no host directories)."""
-    p = Path(str(path))
+    path_text = str(path)
+    is_windows_style = bool(_WIN_ABS_START_EXPORT.match(path_text)) or "\\" in path_text
+    p = PureWindowsPath(path_text) if is_windows_style else Path(path_text)
     name = p.name or "unknown_audio"
     stem = p.stem
     ext = p.suffix
@@ -663,7 +665,7 @@ def publication_audio_path_fields(path: Union[str, Path], *, dataset_root: Optio
     rel = name
     if dataset_root is not None:
         try:
-            rel = Path(p).resolve().relative_to(Path(dataset_root).resolve()).as_posix()
+            rel = Path(path_text).resolve().relative_to(Path(dataset_root).resolve()).as_posix()
         except Exception:
             rel = name
     rel_posix = rel.replace("\\", "/")
@@ -699,12 +701,19 @@ def sanitize_path_for_publication(path: Union[str, Path, None], dataset_root: Op
     """Basename or POSIX path relative to *dataset_root* (never absolute host paths)."""
     if path is None:
         return ""
-    p = Path(str(path))
+    path_text = str(path)
+    # Treat Windows-formatted paths explicitly so basename extraction works on Linux runners.
+    is_windows_style = bool(_WIN_ABS_START_EXPORT.match(path_text)) or "\\" in path_text
+    p = Path(path_text)
     if dataset_root is not None:
         try:
+            if is_windows_style:
+                return PureWindowsPath(path_text).name
             return p.resolve().relative_to(Path(dataset_root).resolve()).as_posix()
         except Exception:
             pass
+    if is_windows_style:
+        return PureWindowsPath(path_text).name or "path_redacted"
     return p.name if p.name else "path_redacted"
 
 
diff --git a/metrics_dictionary.json b/metrics_dictionary.json
index e9ef70f..c602dca 100644
--- a/metrics_dictionary.json
+++ b/metrics_dictionary.json
@@ -84,7 +84,10 @@
       "interpretation": "fraction of the analysed component power that is held by detected harmonic partials.",
       "do_not_interpret_as": "loudness, perceptual prominence, or a fraction of total signal energy (the denominator excludes residual full-spectrum noise outside the analysed component set).",
       "metric_family": "component_energy",
-      "derived_from": ["harmonic_energy_sum", "total_component_energy"],
+      "derived_from": [
+        "harmonic_energy_sum",
+        "total_component_energy"
+      ],
       "independent_for_pca": true
     },
     {
@@ -98,7 +101,10 @@
       "interpretation": "fraction of the analysed component power held by detected inharmonic (non-integer-multiple) partials.",
       "do_not_interpret_as": "perceptual roughness or dissonance; those are separate models.",
       "metric_family": "component_energy",
-      "derived_from": ["inharmonic_energy_sum", "total_component_energy"],
+      "derived_from": [
+        "inharmonic_energy_sum",
+        "total_component_energy"
+      ],
       "independent_for_pca": true
     },
     {
@@ -112,7 +118,10 @@
       "interpretation": "fraction of the analysed component power held by the aggregated sub-bass / ground-noise band below the configured cut-off (default ~200 Hz).",
       "do_not_interpret_as": "a separate noise-floor estimate; this aggregator includes any sub-bass peaks excluded from the harmonic template.",
       "metric_family": "component_energy",
-      "derived_from": ["component_harmonic_energy_ratio", "component_inharmonic_energy_ratio"],
+      "derived_from": [
+        "component_harmonic_energy_ratio",
+        "component_inharmonic_energy_ratio"
+      ],
       "independent_for_pca": false
     },
     {
@@ -126,7 +135,10 @@
       "interpretation": "convenience sum of the inharmonic and sub-bass component shares; non-harmonic share of analysed components.",
       "do_not_interpret_as": "a noise-to-signal ratio; this excludes content outside the analysed peak / sub-bass aggregation.",
       "metric_family": "component_energy",
-      "derived_from": ["component_inharmonic_energy_ratio", "component_subbass_energy_ratio"],
+      "derived_from": [
+        "component_inharmonic_energy_ratio",
+        "component_subbass_energy_ratio"
+      ],
       "independent_for_pca": false
     },
     {
@@ -140,7 +152,12 @@
       "interpretation": "diffuse non-harmonic residual energy fraction; spectral power that survived the noise-floor rejection but is NOT in the accepted harmonic peaks, NOT in the discrete inharmonic peaks, and NOT in the sub-bass region. Captures broadband bow/breath noise that the discrete-inharmonic accounting alone would miss.",
       "do_not_interpret_as": "the same quantity as component_inharmonic_energy_ratio (denominator is intentionally different — H+I+S+residual vs H+I+S — and the masks are disjoint).",
       "metric_family": "component_energy",
-      "derived_from": ["harmonic_energy_sum", "inharmonic_energy_sum", "subbass_energy_sum", "total_filtered_spectral_energy"],
+      "derived_from": [
+        "harmonic_energy_sum",
+        "inharmonic_energy_sum",
+        "subbass_energy_sum",
+        "total_filtered_spectral_energy"
+      ],
       "independent_for_pca": true
     },
     {
@@ -154,7 +171,11 @@
       "interpretation": "total non-harmonic share of the surviving spectrum: discrete inharmonic + sub-bass + diffuse residual. Complementary to component_harmonic_energy_ratio computed over the extended denominator.",
       "do_not_interpret_as": "the arithmetic sum of component_inharmonic_energy_ratio + component_subbass_energy_ratio + component_residual_noise_energy_ratio when those use different denominators (this metric uses H+I+S+residual throughout).",
       "metric_family": "component_energy",
-      "derived_from": ["component_residual_noise_energy_ratio", "harmonic_energy_sum", "total_filtered_spectral_energy"],
+      "derived_from": [
+        "component_residual_noise_energy_ratio",
+        "harmonic_energy_sum",
+        "total_filtered_spectral_energy"
+      ],
       "independent_for_pca": false
     },
     {
@@ -168,7 +189,10 @@
       "interpretation": "binary coefficient used by downstream weighting / dissonance models to blend harmonic and inharmonic contributions.",
       "do_not_interpret_as": "the same number as component_harmonic_energy_ratio; the denominator is intentionally H + I, not H + I + S.",
       "metric_family": "model_weight",
-      "derived_from": ["harmonic_energy_sum", "inharmonic_energy_sum"],
+      "derived_from": [
+        "harmonic_energy_sum",
+        "inharmonic_energy_sum"
+      ],
       "independent_for_pca": true
     },
     {
@@ -182,7 +206,9 @@
       "interpretation": "binary coefficient used by downstream weighting / dissonance models.",
       "do_not_interpret_as": "the same number as component_inharmonic_energy_ratio; the denominator is intentionally H + I, not H + I + S.",
       "metric_family": "model_weight",
-      "derived_from": ["model_harmonic_weight"],
+      "derived_from": [
+        "model_harmonic_weight"
+      ],
       "independent_for_pca": false
     },
     {
@@ -238,7 +264,9 @@
       "interpretation": "Publication-facing column name for the canonical v5 adapted density; use when the internal lineage suffix is not needed in tables.",
       "do_not_interpret_as": "an independent quantity from canonical_density_v5_adapted; values are duplicated for readability only.",
       "metric_family": "density",
-      "derived_from": ["canonical_density_v5_adapted"],
+      "derived_from": [
+        "canonical_density_v5_adapted"
+      ],
       "independent_for_pca": false
     },
     {
@@ -252,7 +280,9 @@
       "interpretation": "canonical, publication-grade run-relative normalised density derived from canonical_density_v5_adapted. Default plotting metric for Canonical_Metrics.",
       "do_not_interpret_as": "an absolute density. The normalisation is run-relative; do not compare across different runs unless the normalization reference is identical. NOTE: density_normalized_global is the canonical density max-norm; density_metric_normalized (Density_Metrics sheet) is a DIFFERENT diagnostic descriptor that max-normalises the weighted partial-sum density_metric_raw, not canonical_density_v5_adapted.",
       "metric_family": "density",
-      "derived_from": ["canonical_density_v5_adapted"],
+      "derived_from": [
+        "canonical_density_v5_adapted"
+      ],
       "independent_for_pca": false
     },
     {
@@ -266,7 +296,9 @@
       "interpretation": "density normalised by the number of detected harmonic orders.",
       "do_not_interpret_as": "energy per partial; the denominator is a count, not a power.",
       "metric_family": "density",
-      "derived_from": ["canonical_density_v5_adapted"],
+      "derived_from": [
+        "canonical_density_v5_adapted"
+      ],
       "independent_for_pca": true
     },
     {
@@ -308,7 +340,9 @@
       "interpretation": "compatibility alias of component_harmonic_energy_ratio. Demoted from canonical → diagnostic in v1.1 of the dictionary because it is the SAME quantity as the explicit canonical name.",
       "do_not_interpret_as": "an independent measurement; for new code use component_harmonic_energy_ratio.",
       "metric_family": "component_energy",
-      "derived_from": ["component_harmonic_energy_ratio"],
+      "derived_from": [
+        "component_harmonic_energy_ratio"
+      ],
       "independent_for_pca": false
     },
     {
@@ -322,7 +356,9 @@
       "interpretation": "compatibility alias of component_inharmonic_energy_ratio.",
       "do_not_interpret_as": "an independent measurement.",
       "metric_family": "component_energy",
-      "derived_from": ["component_inharmonic_energy_ratio"],
+      "derived_from": [
+        "component_inharmonic_energy_ratio"
+      ],
       "independent_for_pca": false
     },
     {
@@ -336,7 +372,9 @@
       "interpretation": "compatibility alias of component_subbass_energy_ratio.",
       "do_not_interpret_as": "a calibrated noise-floor estimate.",
       "metric_family": "component_energy",
-      "derived_from": ["component_subbass_energy_ratio"],
+      "derived_from": [
+        "component_subbass_energy_ratio"
+      ],
       "independent_for_pca": false
     },
     {
@@ -350,7 +388,10 @@
       "interpretation": "linear power ratio between harmonic and inharmonic detected components.",
       "do_not_interpret_as": "a dB value; convert with 10·log10 if a dB reading is needed.",
       "metric_family": "harmonicity",
-      "derived_from": ["harmonic_energy_sum", "inharmonic_energy_sum"],
+      "derived_from": [
+        "harmonic_energy_sum",
+        "inharmonic_energy_sum"
+      ],
       "independent_for_pca": true
     },
     {
@@ -406,7 +447,13 @@
       "interpretation": "Lower-frequency guard: spectral energy below this cutoff in the fixed diagnostic band is classified as subfundamental residual for labelling/audit, not as proven physical sub-bass.",
       "do_not_interpret_as": "the STFT bin width, the orchestral sub-bass limit, or a noise-floor estimate.",
       "metric_family": "validation",
-      "derived_from": ["f0_final_hz", "subfundamental_margin_percent", "min_floor_hz", "max_fraction_of_f0", "leakage_guard_cutoff_hz"],
+      "derived_from": [
+        "f0_final_hz",
+        "subfundamental_margin_percent",
+        "min_floor_hz",
+        "max_fraction_of_f0",
+        "leakage_guard_cutoff_hz"
+      ],
       "independent_for_pca": false
     },
     {
@@ -420,7 +467,9 @@
       "interpretation": "Nominal register margin below f0 used to form percentage_subfundamental_cutoff_hz = f0 * (1 − M/100).",
       "do_not_interpret_as": "a loudness cue or psychoacoustic sharpness metric.",
       "metric_family": "validation",
-      "derived_from": ["f0_final_hz"],
+      "derived_from": [
+        "f0_final_hz"
+      ],
       "independent_for_pca": false
     },
     {
@@ -434,7 +483,10 @@
       "interpretation": "Pure register-policy cutoff line before min-floor, leakage guard, and f0·max_fraction caps.",
       "do_not_interpret_as": "the final adaptive guard; use adaptive_subfundamental_cutoff_hz after caps.",
       "metric_family": "validation",
-      "derived_from": ["f0_final_hz", "subfundamental_margin_percent"],
+      "derived_from": [
+        "f0_final_hz",
+        "subfundamental_margin_percent"
+      ],
       "independent_for_pca": false
     },
     {
@@ -448,7 +500,9 @@
       "interpretation": "Optional lower bound derived from harmonic main-lobe / protection half-width so window leakage just below f0 is not mis-labelled as musical subfundamental content.",
       "do_not_interpret_as": "proof of acoustic leakage level without STFT geometry context.",
       "metric_family": "validation",
-      "derived_from": ["f0_final_hz"],
+      "derived_from": [
+        "f0_final_hz"
+      ],
       "independent_for_pca": false
     },
     {
@@ -476,7 +530,9 @@
       "interpretation": "Upper cap on the adaptive cutoff as a fraction of f0 so the guard never approaches Nyquist or swallows the fundamental.",
       "do_not_interpret_as": "the detected bandwidth of the note.",
       "metric_family": "validation",
-      "derived_from": ["f0_final_hz"],
+      "derived_from": [
+        "f0_final_hz"
+      ],
       "independent_for_pca": false
     },
     {
@@ -490,7 +546,10 @@
       "interpretation": "Effective margin (percent of f0) implied by the final adaptive cutoff after all floors/guards/caps.",
       "do_not_interpret_as": "identical to subfundamental_margin_percent when caps bind; compare both.",
       "metric_family": "validation",
-      "derived_from": ["f0_final_hz", "adaptive_subfundamental_cutoff_hz"],
+      "derived_from": [
+        "f0_final_hz",
+        "adaptive_subfundamental_cutoff_hz"
+      ],
       "independent_for_pca": false
     },
     {
@@ -504,7 +563,9 @@
       "interpretation": "True when an adaptive subfundamental guard was computed from a valid f0; false when f0 invalid and policy returns sentinel NaNs.",
       "do_not_interpret_as": "evidence that the recording is in tune.",
       "metric_family": "validation",
-      "derived_from": ["f0_final_hz"],
+      "derived_from": [
+        "f0_final_hz"
+      ],
       "independent_for_pca": false
     },
     {
@@ -518,7 +579,9 @@
       "interpretation": "Documents which guard branch produced the exported cutoff metadata.",
       "do_not_interpret_as": "user-facing legal policy text.",
       "metric_family": "validation",
-      "derived_from": ["f0_final_hz"],
+      "derived_from": [
+        "f0_final_hz"
+      ],
       "independent_for_pca": false
     },
     {
@@ -546,7 +609,10 @@
       "interpretation": "Records whether the adaptive cutoff was taken from the per-note analysis export or recomputed at compile from f0_final_hz.",
       "do_not_interpret_as": "the numeric cutoff value.",
       "metric_family": "provenance",
-      "derived_from": ["f0_final_hz", "adaptive_subfundamental_cutoff_hz"],
+      "derived_from": [
+        "f0_final_hz",
+        "adaptive_subfundamental_cutoff_hz"
+      ],
       "independent_for_pca": false
     },
     {
@@ -602,7 +668,10 @@
       "interpretation": "Audit field: which input dominated the final adaptive_subfundamental_cutoff_hz after caps.",
       "do_not_interpret_as": "the cutoff frequency in Hz.",
       "metric_family": "provenance",
-      "derived_from": ["adaptive_subfundamental_cutoff_hz", "f0_final_hz"],
+      "derived_from": [
+        "adaptive_subfundamental_cutoff_hz",
+        "f0_final_hz"
+      ],
       "independent_for_pca": false
     },
     {
@@ -728,7 +797,11 @@
       "interpretation": "denominator audit for the component_* ratios.",
       "do_not_interpret_as": "total signal energy; this excludes content outside the analysed peak / sub-bass aggregation.",
       "metric_family": "component_energy",
-      "derived_from": ["harmonic_energy_sum", "inharmonic_energy_sum", "subbass_energy_sum"],
+      "derived_from": [
+        "harmonic_energy_sum",
+        "inharmonic_energy_sum",
+        "subbass_energy_sum"
+      ],
       "independent_for_pca": false
     },
     {
@@ -756,7 +829,12 @@
       "interpretation": "diffuse non-harmonic residual: spectral energy that survived the noise-floor rejection but is NOT in the accepted harmonic peaks, NOT in the discrete inharmonic peaks, and NOT in the sub-bass region.",
       "do_not_interpret_as": "an alias of inharmonic_energy_sum; this is a separate residual bucket.",
       "metric_family": "component_energy",
-      "derived_from": ["total_filtered_spectral_energy", "harmonic_energy_sum", "inharmonic_energy_sum", "subbass_energy_sum"],
+      "derived_from": [
+        "total_filtered_spectral_energy",
+        "harmonic_energy_sum",
+        "inharmonic_energy_sum",
+        "subbass_energy_sum"
+      ],
       "independent_for_pca": false
     },
     {
@@ -952,7 +1030,10 @@
       "interpretation": "deprecated: amplitude-based combined density.",
       "do_not_interpret_as": "an energy ratio or canonical density.",
       "metric_family": "legacy_compatibility",
-      "derived_from": ["legacy_harmonic_density", "legacy_inharmonic_density"],
+      "derived_from": [
+        "legacy_harmonic_density",
+        "legacy_inharmonic_density"
+      ],
       "independent_for_pca": false
     },
     {
@@ -966,7 +1047,10 @@
       "interpretation": "deprecated: 'harmonic percentage' computed on amplitude sums.",
       "do_not_interpret_as": "the same as component_harmonic_energy_ratio (different denominator AND quantity type).",
       "metric_family": "legacy_compatibility",
-      "derived_from": ["legacy_harmonic_density", "legacy_inharmonic_density"],
+      "derived_from": [
+        "legacy_harmonic_density",
+        "legacy_inharmonic_density"
+      ],
       "independent_for_pca": false
     },
     {
@@ -980,7 +1064,9 @@
       "interpretation": "deprecated: complement of legacy_harmonic_density_percentage.",
       "do_not_interpret_as": "the same as component_inharmonic_energy_ratio.",
       "metric_family": "legacy_compatibility",
-      "derived_from": ["legacy_harmonic_density_percentage"],
+      "derived_from": [
+        "legacy_harmonic_density_percentage"
+      ],
       "independent_for_pca": false
     },
     {
@@ -994,7 +1080,9 @@
       "interpretation": "compatibility alias; prefer component_harmonic_energy_ratio in new code.",
       "do_not_interpret_as": "a separate or independent measurement.",
       "metric_family": "legacy_compatibility",
-      "derived_from": ["component_harmonic_energy_ratio"],
+      "derived_from": [
+        "component_harmonic_energy_ratio"
+      ],
       "independent_for_pca": false
     },
     {
@@ -1008,7 +1096,9 @@
       "interpretation": "compatibility alias.",
       "do_not_interpret_as": "an independent measurement.",
       "metric_family": "legacy_compatibility",
-      "derived_from": ["component_inharmonic_energy_ratio"],
+      "derived_from": [
+        "component_inharmonic_energy_ratio"
+      ],
       "independent_for_pca": false
     },
     {
@@ -1022,7 +1112,9 @@
       "interpretation": "compatibility alias.",
       "do_not_interpret_as": "an independent measurement.",
       "metric_family": "legacy_compatibility",
-      "derived_from": ["component_subbass_energy_ratio"],
+      "derived_from": [
+        "component_subbass_energy_ratio"
+      ],
       "independent_for_pca": false
     },
     {
@@ -1036,7 +1128,9 @@
       "interpretation": "compatibility alias.",
       "do_not_interpret_as": "an independent measurement.",
       "metric_family": "legacy_compatibility",
-      "derived_from": ["component_total_inharmonic_energy_ratio"],
+      "derived_from": [
+        "component_total_inharmonic_energy_ratio"
+      ],
       "independent_for_pca": false
     },
     {
@@ -1092,7 +1186,11 @@
       "interpretation": "unweighted diagnostic total of the three per-band partial sums.",
       "do_not_interpret_as": "the final density metric; it ignores the canonical component_*_energy_ratio weighting. Plot density_metric_normalized (Density_Metrics) or density_normalized_global (Canonical_Metrics) instead.",
       "metric_family": "legacy_compatibility",
-      "derived_from": ["Harmonic Partials sum", "Inharmonic Partials sum", "Sub-bass sum"],
+      "derived_from": [
+        "Harmonic Partials sum",
+        "Inharmonic Partials sum",
+        "Sub-bass sum"
+      ],
       "independent_for_pca": false
     },
     {
@@ -1107,7 +1205,7 @@
       "do_not_interpret_as": "an independent canonical descriptor; it is an additive term of density_metric_raw and shares the latter's run-relative interpretation. NOT for publication.",
       "metric_family": "density",
       "derived_from": [
-        "harmonic_density_sum",
+        "Harmonic Partials sum",
         "component_harmonic_energy_ratio"
       ],
       "independent_for_pca": false
@@ -1124,7 +1222,7 @@
       "do_not_interpret_as": "an independent canonical descriptor; additive term of density_metric_raw.",
       "metric_family": "density",
       "derived_from": [
-        "inharmonic_density_sum",
+        "Inharmonic Partials sum",
         "component_inharmonic_energy_ratio"
       ],
       "independent_for_pca": false
@@ -1141,7 +1239,7 @@
       "do_not_interpret_as": "an independent canonical descriptor; additive term of density_metric_raw.",
       "metric_family": "density",
       "derived_from": [
-        "subbass_density_sum",
+        "Sub-bass sum",
         "component_subbass_energy_ratio"
       ],
       "independent_for_pca": false
@@ -1150,7 +1248,7 @@
       "name": "density_weighted_sum",
       "status": "diagnostic",
       "formula": "harmonic_density_sum * w_H + inharmonic_density_sum * w_I + subbass_density_sum * w_S",
-      "quantity_type": "density",
+      "quantity_type": "amplitude",
       "denominator": "n/a (raw, unbounded)",
       "unit": "depends on compile weight_function (linear ~ amplitude scale; log ~ log-density scale)",
       "source": "compile_metrics.extract_density_components_from_per_note_workbook",
@@ -1158,9 +1256,9 @@
       "do_not_interpret_as": "a linear sum of Amplitude_raw (see harmonic_amplitude_sum). Not invariant to weight_function changes. Not a canonical publication metric — prefer effective_partial_density on Canonical_Metrics.",
       "metric_family": "density",
       "derived_from": [
-        "harmonic_density_sum",
-        "inharmonic_density_sum",
-        "subbass_density_sum",
+        "Harmonic Partials sum",
+        "Inharmonic Partials sum",
+        "Sub-bass sum",
         "component_harmonic_energy_ratio",
         "component_inharmonic_energy_ratio",
         "component_subbass_energy_ratio"
@@ -1171,14 +1269,16 @@
       "name": "density_log_weighted",
       "status": "diagnostic",
       "formula": "log10(1 + density_weighted_sum)",
-      "quantity_type": "density",
+      "quantity_type": "amplitude",
       "denominator": "n/a",
       "unit": "log10 scale (dimensionless argument)",
       "source": "compile_metrics.extract_density_components_from_per_note_workbook",
       "interpretation": "log-space view of density_weighted_sum. Default auto-plot preference on Density_Metrics sheet when present (publication_chart_policy).",
       "do_not_interpret_as": "independent of compile weight_function; it inherits sensitivity from density_weighted_sum.",
       "metric_family": "density",
-      "derived_from": ["density_weighted_sum"],
+      "derived_from": [
+        "density_weighted_sum"
+      ],
       "independent_for_pca": false
     },
     {
@@ -1210,28 +1310,33 @@
       "interpretation": "Density_Metrics-sheet default plotting metric. Run-relative normalization of density_metric_raw to [0, 1]; suitable for comparison *within* one compiled workbook. The canonical, corpus-wide normalized density descriptor for publication is density_normalized_global (Canonical_Metrics, derived from canonical_density_v5_adapted).",
       "do_not_interpret_as": "comparable across different runs unless the normalization reference (max(density_metric_raw)) is identical. Not a canonical publication metric — prefer density_normalized_global for cross-run publication. Run-relative normalization; do not compare across different runs unless the normalization reference is identical. NOTE: previous versions aliased density_metric_normalized to density_normalized_global; the two are now distinct descriptors.",
       "metric_family": "density",
-      "derived_from": ["density_metric_raw"],
+      "derived_from": [
+        "density_metric_raw"
+      ],
       "independent_for_pca": false
     },
     {
       "name": "Combined Density Metric",
       "status": "legacy",
       "formula": "Stage-1 combined_density_metric_value (log/expm1 or calculate_combined_density_metric on harmonic + inharmonic legacy scalars)",
-      "quantity_type": "density",
+      "quantity_type": "amplitude",
       "denominator": "n/a",
       "unit": "legacy apply_density_metric scale (unbounded)",
       "source": "proc_audio (Legacy_Density_Metrics sheet) / compile_metrics merge",
       "interpretation": "v5-style combined harmonic/inharmonic density scalar. Stronger dynamic separation than density_weighted_sum under log compile on some corpora.",
       "do_not_interpret_as": "equal to density_weighted_sum or the research mean (DWS+CDM)/2; not on Density_Metrics allow-list.",
       "metric_family": "legacy_compatibility",
-      "derived_from": ["Spectral Density Metric", "Filtered Density Metric"],
+      "derived_from": [
+        "Spectral Density Metric",
+        "Filtered Density Metric"
+      ],
       "independent_for_pca": false
     },
     {
       "name": "Spectral Density Metric",
       "status": "legacy",
       "formula": "spectral_density_metric_value (whole-spectrum legacy path; masking off when spectral_masking_enabled=False)",
-      "quantity_type": "density",
+      "quantity_type": "amplitude",
       "denominator": "n/a",
       "unit": "legacy power/average density scale",
       "source": "proc_audio (Legacy_Density_Metrics sheet)",
@@ -1245,7 +1350,7 @@
       "name": "Filtered Density Metric",
       "status": "legacy",
       "formula": "filtered_density_metric_value = apply_density_metric on filtered_list_df amplitudes",
-      "quantity_type": "density",
+      "quantity_type": "amplitude",
       "denominator": "n/a",
       "unit": "legacy apply_density_metric scale",
       "source": "proc_audio (Legacy_Density_Metrics sheet)",
@@ -1259,28 +1364,34 @@
       "name": "Weighted Combined Metric",
       "status": "legacy",
       "formula": "f(alpha * SDM + beta * FDM) with f from compile weight_function (e.g. log -> log1p)",
-      "quantity_type": "density",
+      "quantity_type": "amplitude",
       "denominator": "n/a",
       "unit": "depends on weight_function",
       "source": "compile_metrics.apply_weighted_combination",
       "interpretation": "v5-style weighted legacy combination using model_harmonic_weight / model_inharmonic_weight (H/(H+I)), not measured H+I+S energy ratios.",
       "do_not_interpret_as": "density_weighted_sum_cdm_mean; forbidden on Density_Metrics sheet.",
       "metric_family": "legacy_compatibility",
-      "derived_from": ["Spectral Density Metric", "Filtered Density Metric"],
+      "derived_from": [
+        "Spectral Density Metric",
+        "Filtered Density Metric"
+      ],
       "independent_for_pca": false
     },
     {
       "name": "density_weighted_sum_cdm_mean",
       "status": "diagnostic",
       "formula": "(density_weighted_sum + Combined Density Metric) / 2",
-      "quantity_type": "density",
+      "quantity_type": "amplitude",
       "denominator": "n/a",
       "unit": "mixed scale (editorial average of two unlike definitions)",
       "source": "tools/export_research_density_workbook.build_spectral_density_metrics",
       "interpretation": "Research-workbook-only editorial blend for plotting when a single column is desired. Not computed at compile time.",
       "do_not_interpret_as": "a canonical acoustic measure, Weighted Combined Metric, or energy-weighted density.",
       "metric_family": "density",
-      "derived_from": ["density_weighted_sum", "Combined Density Metric"],
+      "derived_from": [
+        "density_weighted_sum",
+        "Combined Density Metric"
+      ],
       "independent_for_pca": false
     },
     {
diff --git a/pyproject.toml b/pyproject.toml
index e4ff7bb..5383386 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,7 @@ name = "soundspectranalyse"
 version = "3.7.0"
 description = "Advanced spectral analysis tool for acoustic research with harmonic-order-aware spectral processing"
 readme = "README.md"
-requires-python = ">=3.9"
+requires-python = ">=3.10,<3.12"
 license = {text = "Scientific Research Use"}
 authors = [
     {name = "Research Team", email = "research@example.com"}
@@ -17,7 +17,6 @@ classifiers = [
     "Intended Audience :: Science/Research",
     "Topic :: Scientific/Engineering",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
 ]
@@ -105,4 +104,4 @@ markers = [
 
 [tool.black]
 line-length = 100
-target-version = ['py38', 'py39', 'py310', 'py311']
+target-version = ['py310', 'py311']
diff --git a/requirements-dev.txt b/requirements-dev.txt
index d7876dc..44e9dd2 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -4,6 +4,7 @@
 # Testing framework
 pytest>=7.0.0,<8.0.0
 pytest-cov>=3.0.0,<4.0.0
+psutil>=5.9.0,<6.0.0
 
 # Code coverage (compatible with numba)
 # Note: coverage 6.x is compatible with numba 0.56-0.59
diff --git a/tests/benchmarks/audio/harmonic_stack_220.wav b/tests/benchmarks/audio/harmonic_stack_220.wav
new file mode 100644
index 0000000..db8185a
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diff --git a/tests/benchmarks/audio/inharmonic_injection.wav b/tests/benchmarks/audio/inharmonic_injection.wav
new file mode 100644
index 0000000..481f228
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diff --git a/tests/benchmarks/audio/pure_sine_440.wav b/tests/benchmarks/audio/pure_sine_440.wav
new file mode 100644
index 0000000..d5fcff3
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diff --git a/tests/benchmarks/audio/subbass_injection.wav b/tests/benchmarks/audio/subbass_injection.wav
new file mode 100644
index 0000000..4faca14
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