feat(dsp): M1 DSP completion + broadened test coverage + user docs

CHANGELOG.md

@@ -7,6 +7,25 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.1.0] - 2026-07-14
+
 ### Added
 
 - Project bootstrap: README, license, contributing guide, architecture and build docs, ADRs, and CI workflow.
+- Full v1.0 `AudioProcessorValueTreeState` parameter layout (frozen parameter IDs) covering IO/global, noise gate, crossover, low band, high band, EQ, and IR loader.
+- LR4 (Linkwitz-Riley 4th order) crossover band-split (`src/dsp/Crossover`), flat-sum tested, with a latency-compensation framework/seam in the processor.
+- **DSP completion (M1):** the full v1.0 signal path is wired and live:
+  - Full-band input noise gate (`src/dsp/NoiseGateStage`), off by default.
+  - Low-band parallel ("New York style") compressor with makeup gain and wet/dry mix (`src/dsp/ParallelCompressor`).
+  - High-band distortion engine (`src/dsp/Voicing`) with three selectable voicings — **Gnaw** (op-amp hard clip), **Wool** (cascaded soft-clip fuzz with mid scoop), **Razor** (tight overdrive: pre-clip highpass, soft clip, mid hump) — each running its nonlinear shaping stage 4x oversampled (FIR half-band equiripple) to control aliasing, with drive, tone, and clean/distorted blend controls.
+  - Post-sum 4-band EQ (`src/dsp/BandEQ`: LowShelf / Peak / Peak / HighShelf), off by default.
+  - Cab-sim IR loader (`src/dsp/IRLoader`, `juce::dsp::Convolution`-based), off by default, safe-by-default (bit-exact passthrough with no IR loaded, at every session sample rate); `loadImpulseResponse()` is the DSP-side seam a future GUI/preset system will call to load user or factory IRs.
+  - Latency compensation extended to cover the high band's oversampling latency: reported to the host via `setLatencySamples`, low band delay-compensated to match, high band's own clean/distorted `DryWetMixer` blend delay-compensated too.
+  - `src/dsp/RealtimeCoefficients.h`: shared real-time-safe (zero-allocation) `juce::dsp::IIR` coefficient update helper, used by `BandEQ` and `Voicing`'s mid/tone filters.
+- Broadened Catch2 test suite (issue #43): dedicated test files for every new DSP stage (`NoiseGateTests`, `ParallelCompressorTests`, `VoicingTests`, `BandEQTests`, `IRLoaderTests`), plus sample-rate sweeps (44.1–192 kHz), mono/stereo bus-configuration tests, extreme-parameter-automation and long-run NaN/Inf stability soak tests (`SampleRateAndRobustnessTests`). Existing gain-staging/latency/passthrough tests updated to account for the now-live (non-transparent-by-default) compressor and voicing stages.
+- `docs/manual.md`: full user manual — what the plugin is, where it sits in a symphonic-metal chain, signal-flow description, complete parameter reference, and usage tips.
+
+### Changed
+
+- `docs/architecture.md`: signal-flow diagram and module map updated to match the new full signal path; new sections documenting the real-time-safe filter-coefficient pattern, the IR loader's safe-by-default behaviour, and the extended latency-compensation design (including the `DryWetMixer` priming gotcha).
+- `README.md`: feature list, signal-flow diagram, and roadmap table updated to match the live DSP and the project's actual milestone scheme (M1 DSP completion & test coverage → M2 presets & state → M3 GUI & accessibility → M4 release).

CLAUDE.md

@@ -5,12 +5,14 @@ Per-repo working memory for Claude Code sessions on this plugin. Part of the **M
 ## What this is
 Twist Your Guts is a Parallax-style **parallel bass processor** for metal: it LR4-splits the bass into low/high bands, parallel-compresses the lows, runs the highs through selectable distortion voicings, then sums back through a 4-band EQ and an IR cabinet loader. AU / VST3 / Standalone.
 
-## Status (pre-1.0)
-M0 bootstrap complete (scaffold, CI, docs, ADRs). The LR4 crossover + latency framework is the first DSP landed with tests; the full v1.0 signal path (compressor, distortion voicings, gate, EQ, IR loader) is in progress. See GitHub **milestones/issues** for open work, and `README.md` for the full v1.0 feature scope and signal-flow diagram.
-
-## DSP (v1.0 target)
-`Input Trim → Gate → LR4 split (60–1000 Hz) → [Low: parallel comp] + [High: distortion voicing (Gnaw/Wool/Razor) → drive → tone → blend] → delay-compensated sum → 4-band EQ → IR loader → Output`.
-- Crossover already implemented in `src/dsp/Crossover.{h,cpp}` (LR4, flat-sum tested) — this is the canonical crossover the suite's `triptych` multiband reuses.
+## Status (pre-1.0, v0.1.0)
+M0 bootstrap and M1 "DSP completion & test coverage" are both done: the full v1.0 signal path is wired and tested (gate, LR4 crossover, parallel low-band compressor, three oversampled high-band voicings, post-sum 4-band EQ, IR loader, latency compensation). Not yet done: preset manager/versioned state (M2), custom GUI/metering/accessibility (M3), signing/notarization/v1.0.0 release (M4). Voicing character (drive-gain ranges, mid-filter hump/scoop settings) is engineering-tuned, not yet ear-tuned against reference material. IR loader has no bundled factory IRs and no GUI file browser yet (DSP engine is fully live; file-loading is a `loadImpulseResponse()` seam a future GUI/preset system will call). See GitHub **milestones/issues** for open work, `README.md` for the feature scope and signal-flow diagram, and `docs/manual.md` for the full parameter reference.
+
+## DSP (v1.0 target — fully wired as of M1)
+`Input Trim → Gate → LR4 split (60–1000 Hz) → [Low: parallel comp → makeup → mix → level] + [High: voicing (Gnaw/Wool/Razor, 4x oversampled) → drive → tone → blend → level] → delay-compensated sum → 4-band EQ → IR loader → optional safety clip → Output Trim`.
+- Each stage lives in its own `src/dsp/*.{h,cpp}` class with a dedicated Catch2 test file: `Crossover` (LR4 split/sum, flat-sum tested — canonical crossover the suite's `triptych` multiband reuses), `NoiseGateStage`, `ParallelCompressor`, `Voicing` (oversampling + latency reporting), `BandEQ`, `IRLoader`.
+- `src/dsp/RealtimeCoefficients.h`: shared helper for updating `juce::dsp::IIR` filter coefficients from the audio thread without heap allocation (`ArrayCoefficients` stack-only computation + in-place raw-storage write). Used by `BandEQ` and `Voicing`.
+- Latency: only `Voicing`'s 4x oversampling adds sample latency; reported via `setLatencySamples`, low band delay-compensated to match. See `docs/architecture.md`'s "Latency compensation" section, including the `DryWetMixer` priming gotcha.
 - Params via APVTS (`src/params/`).
 
 ## Build & test

README.md

@@ -5,26 +5,27 @@
 [![CI](https://github.com/yves-vogl/twist-your-guts/actions/workflows/ci.yml/badge.svg)](https://github.com/yves-vogl/twist-your-guts/actions/workflows/ci.yml)
 [![License: AGPL v3](https://img.shields.io/badge/License-AGPL%20v3-blue.svg)](https://www.gnu.org/licenses/agpl-3.0)
 
-> **Work in progress.** Twist Your Guts is pre-1.0 and under active development. There are no built binaries or releases yet — building from source is currently the only way to run it. Expect breaking changes until v1.0.0 ships (see [Roadmap](#roadmap)).
+> **Work in progress.** Twist Your Guts is pre-1.0 and under active development (v0.1.0). There are no built binaries or releases yet — building from source is currently the only way to run it. Expect breaking changes until v1.0.0 ships (see [Roadmap](#roadmap)).
 
 ## What it is
 
-Twist Your Guts is a Parallax-style bass plugin built on JUCE 8. It splits your bass signal into low and high bands with a linear-phase-adjacent Linkwitz-Riley crossover, compresses the low band in parallel, and runs the high band through a choice of three distortion voicings before summing everything back together through a 4-band EQ and an impulse-response (cab sim) loader.
+Twist Your Guts is a Parallax-style bass plugin built on JUCE 8. It splits your bass signal into low and high bands with a linear-phase-adjacent Linkwitz-Riley crossover, compresses the low band in parallel, and runs the high band through a choice of three distortion voicings before summing everything back together through a 4-band EQ and an impulse-response (cab sim) loader. See [`docs/manual.md`](docs/manual.md) for the full parameter reference and usage tips.
 
-## Features (v1.0 scope)
+## Features
 
+- **Noise gate** — full-band, ahead of the crossover split
 - **LR4 crossover band-split** — 4th-order Linkwitz-Riley split, adjustable 60 Hz – 1000 Hz (default 250 Hz)
-- **Low band**: parallel compressor with wet/dry mix and output level
-- **High band**: three distortion voicings, each with independent drive/tone
-  - **Gnaw** — hard clip
-  - **Wool** — fuzz
-  - **Razor** — tight overdrive
+- **Low band**: parallel ("New York style") compressor with makeup gain, wet/dry mix, and output level
+- **High band**: three distortion voicings, each 4x oversampled to keep aliasing under control, with independent drive/tone
+  - **Gnaw** — op-amp-style hard clip
+  - **Wool** — cascaded soft-clip fuzz with a mid scoop
+  - **Razor** — tight overdrive: pre-clip highpass, soft clip, mid hump
   - Clean/distorted blend control per voicing, plus output level
-- **Noise gate** on the input stage
-- **4-band EQ** post-sum
-- **IR loader** (cabinet simulation) on the output stage
-- **Presets** with full state save/recall
-- **Metering** throughout the signal chain
+- **4-band EQ** post-sum (LowShelf / Peak / Peak / HighShelf)
+- **IR loader** (cabinet simulation) on the output stage — convolution engine is live; bundled factory IRs and a GUI file browser land in a later milestone
+- **Delay-compensated signal path** — the high band's oversampling latency is reported to the host and the low band is time-aligned to match
+- **Presets** with full state save/recall *(planned — a dedicated preset manager/versioning scheme is a later milestone; APVTS state save/load already round-trips today)*
+- **Metering** throughout the signal chain *(planned, alongside the custom GUI)*
 
 ## Signal flow
 
@@ -34,8 +35,9 @@ Input Trim → Gate → LR4 Split (60–1000 Hz, default 250 Hz)
         ┌─────────────┴─────────────┐
         │                           │
      Low band                   High band
-  Comp → Mix → Level    Voicing → Drive → Tone → Blend → Level
-        │                           │
+  Parallel Comp        Voicing → Drive → Tone → Blend
+  → Makeup → Mix                    │
+        │→ Level              → Level
         └─────────────┬─────────────┘
                        │
               Sum (delay-compensated)
@@ -44,10 +46,26 @@ Input Trim → Gate → LR4 Split (60–1000 Hz, default 250 Hz)
                        │
                   IR loader
                        │
-                     Output
+              Safety Clip (optional)
+                       │
+                 Output Trim
 ```
 
-The high band runs through oversampling for the distortion stage; the low band is delay-compensated to stay time-aligned with it before the sum. See [`docs/architecture.md`](docs/architecture.md) for the full breakdown, including the latency-compensation strategy.
+The high band runs 4x oversampled for the distortion stage; the low band is delay-compensated to stay time-aligned with it before the sum. See [`docs/architecture.md`](docs/architecture.md) for the full breakdown, including the latency-compensation strategy, and [`docs/manual.md`](docs/manual.md) for the full parameter reference.
+
+## Parameters
+
+See [`docs/manual.md`](docs/manual.md) for the complete, musically-annotated parameter reference. Summary:
+
+| Section | Parameters |
+|---|---|
+| IO / Global | Input Gain, Output Gain, Bypass, Safety Clip |
+| Noise Gate | Enable, Threshold, Ratio, Attack, Release |
+| Crossover | Frequency (60–1000 Hz) |
+| Low band | Comp Threshold/Ratio/Attack/Release/Makeup/Mix, Level |
+| High band | Voicing (Gnaw/Wool/Razor), Drive, Tone, Blend, Level |
+| EQ | Enable, Low Shelf Freq/Gain, Peak 1 Freq/Gain/Q, Peak 2 Freq/Gain/Q, High Shelf Freq/Gain |
+| IR loader | Enable, Mix |
 
 ## Installation
 
@@ -87,14 +105,11 @@ ctest --test-dir build --output-on-failure
 
 | Milestone | Description | Status |
 |---|---|---|
-| M0 | Bootstrap — project skeleton, CI, docs | In progress |
-| M1 | DSP core — crossover + latency framework | Planned |
-| M2 | Dynamics — gate + compressor | Planned |
-| M3 | Distortion engine — oversampling, 3 voicings | Planned |
-| M4 | EQ + IR loader | Planned |
-| M5 | State & presets | Planned |
-| M6 | Custom GUI | Planned |
-| M7 | Release engineering — signing, notarization, installers, v1.0.0 | Planned |
+| M0 | Bootstrap — project skeleton, CI, docs | Done |
+| M1 | DSP completion & test coverage — gate, crossover, parallel compressor, 3 voicings (oversampled), 4-band EQ, IR loader, latency compensation, broadened test suite | Done (v0.1.0) |
+| M2 | Presets & state recall — preset manager, factory presets, versioned state | Planned |
+| M3 | GUI & accessibility — custom LookAndFeel, metering UI, accessibility pass | Planned |
+| M4 | Release: signing, notarization, v1.0.0 — installers, tagged release | Planned |
 
 ## License