Crypta

Split your bass. Compress the lows. Twist the guts out of the highs.

Formerly Twist Your Guts, renamed to Crypta as part of the suite's move to Basilica Audio naming (the crypt: the basilica's low-end foundation). If you have a v0.1.0-era session referencing the old plugin identity (com.yvesvogl.twistyourguts, plugin code Tygt), see the [Unreleased] entry in CHANGELOG.md — the new bundle ID and plugin code (com.yvesvogl.crypta, Cryp) mean DAWs treat this as a new plugin, so existing sessions will need to be re-pointed at the new plugin.

Work in progress. Crypta is pre-1.0 and under active development. Binaries for macOS and Windows are published on the Releases page (macOS builds are signed, notarized and stapled); building from source works too. Expect breaking changes until v1.0.0 ships (see Roadmap).

What it is

Crypta is a Parallax-style bass plugin built on JUCE 8. As of v0.2.0 it splits your bass signal into three bands — low, mid, and high — with two cascaded 4th-order Linkwitz-Riley crossovers, compresses the low band in parallel, drives the mid band with staged saturation, 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. v0.2.0 also adds a full preset system (factory + user presets, import/export, German localisation). See docs/manual.md for the full parameter reference and usage tips, and docs/design-brief.md/docs/research-notes.md for the research behind the v0.2.0 topology rebuild.

Features

• Noise gate — full-band, ahead of both crossover splits
• Two cascaded LR4 crossover splits — Split Low (60–400 Hz, default 120 Hz) and Split High (300–2000 Hz, default 600 Hz), building a genuine 3-band (low/mid/high) topology, replacing v0.1.x's 2-band split
• Low band: parallel "glue" compressor (re-sourced fast/gentle ballistics, ratio 2:1 / attack 3 ms / release 6 ms) with makeup gain, wet/dry mix, and output level
• Mid band (NEW): staged/cascaded drive-only saturation, no filter/tone/blend — a distinct "throatier" character separate from the high band
• High band: three distortion voicings, oversampled to keep aliasing under control, with a shared, voicing-independent Tight pre-drive highpass
• Circuit drive engine (v0.3.0): the mid and high bands rebuilt from circuit models with antiderivative antialiasing, sharing one oversampling region — measured 25–30 dB less aliasing than the previous engine, which ships on as the bit-identical Classic fallback
• Smooth RMS low-band detector and a Modern gate (v0.3.0): a log-domain RMS detector that stops the low band tremoloing on sustained notes, and a gate with hysteresis, hold, a sidechain highpass and a straight-line release
  • Gnaw — op-amp-style hard clip
  • Wool — cascaded soft-clip fuzz with a mid scoop
  • Razor — tight overdrive: soft clip, mid hump
  • Clean/distorted blend control, plus drive/tone/output level
• 4-band EQ post-sum (LowShelf / Peak / Peak / HighShelf), re-anchored default frequencies (80/500/2800/5000 Hz, sourced from the same design lineage's hardware tone stack)
• IR loader (cabinet simulation), relocated in v0.2.0 to process only the Mid+High post-sum signal — the low band never passes through it, matching the reference class's own architecture. Convolution engine is live; bundled factory IRs and a GUI file browser land in a later milestone
• Delay-compensated, phase-aligned signal path — the Mid+High branch's shared oversampling latency is reported to the host, the low band is time-aligned to match, and a phase-alignment allpass filter keeps the cascaded three-way sum flat-magnitude
• Presets — factory + user presets, save/save-as/delete, import/export (single files and zip banks), German localisation of the preset UI frame
• State migration — a v0.1.x session's single crossover frequency is migrated to the new Split High parameter on load
• Custom vector GUI — a fully drawn (no bitmaps) black-and-gold editor: ten sections laid out in signal order carrying all 51 parameters, pointer knobs with engraved scale rings, lamp toggles, and a resizable, aspect-locked window whose zoom level is saved with the session
• Metering — input and output peak plus gate and low-band compressor gain reduction, on four needle meters driven at 30 Hz from the lock-free metering taps
• Accessible by design — full keyboard operability with WAI-ARIA-style stepping, a visible focus ring, screen-reader names/roles/values with units, signal-flow focus order and WCAG AA contrast, all enforced by tests

Signal flow

Input Trim → Gate → LR4 Split Low (60–400 Hz, default 120 Hz)
                      │
        ┌─────────────┴───────────────────────────────┐
        │                                              │
     Low band                              Remainder → LR4 Split High (300–2000 Hz, default 600 Hz)
  Parallel Comp → Level                                  │
        │                          ┌───────────────────┴───────────────────┐
        │                       Mid band                              High band
        │                    Drive → Level          Tight → Voicing → Drive → Tone → Blend → Level
        │                          └───────────────────┬───────────────────┘
        │                                          Mid+High sum → IR loader (cab sim)
        │                                                │
        └──────────── Phase-align + delay ───────────────┘
                                 │
                       Sum (delay-compensated)
                                 │
                            4-band EQ
                                 │
                       Safety Clip (optional)
                                 │
                            Output Trim

The Mid and High bands each run 4x oversampled (identically configured, so their latencies match exactly); the low band is delay-compensated and phase-aligned to stay both time- and magnitude-flat with them before the sum. See docs/architecture.md for the full breakdown, including the latency-compensation strategy and the phase-alignment proof, and docs/manual.md for the full parameter reference.

Parameters

See 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	Split Low (60–400 Hz), Split High (300–2000 Hz)
Low band	Comp Threshold/Ratio/Attack/Release/Makeup/Mix, Level
Mid band	Drive, Level
High band	Tight, 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

Interface & brand

The plugin icon — a gold serpent coiled around a bass clef, antique-gold bas-relief on a flat near-black squircle — is the header image above, and is committed at docs/assets/icon.png (1024×1024) and docs/assets/icon-256.png (256×256). Motif, palette, master locations and the archived logo drafts are documented in docs/branding.md. All artwork is self-made and therefore license-clean under this repo's AGPLv3.

Editor. Crypta ships the suite's vector editor: black-and-gold, drawn entirely at runtime (no bitmaps), with EB Garamond embedded as the only typographic asset. Ten section panels follow the signal flow and carry all 51 parameters — 44 pointer knobs with engraved scale rings and 7 lamp toggles — alongside four needle meters (input/output peak, gate and low-band-compressor gain reduction). The window is resizable and aspect-locked between 60 % and 180 %, and the zoom level is saved with the session. Which control drives which parameter is tabulated in docs/gui-mapping.md; the component architecture is in docs/architecture.md.

Screenshot.

The preview above is generated, not mocked up: the GUI test suite takes an offscreen snapshot of the real editor, asserts it is not blank, and writes it to build/gui-preview.png (tests/gui/GuiPreviewSnapshotTests.cpp); that file is what is committed as docs/gui-preview.png. See docs/branding.md for the convention.

Documentation

• docs/manual.md — the user manual: what every control does, and how to use it
• docs/presets.md — what each factory preset is for
• CHANGELOG.md — what shipped in each release
• Crypta on basilica-audio.github.io — the product page (English and German)

Installation

Download from the Releases page. Every asset ships with a .sha256 file, so a download can be verified with shasum -a 256 -c <asset>.sha256.

macOS — installer (recommended)

Open crypta-vX.Y.Z-macos.pkg and pick which formats to install. It puts the AU in /Library/Audio/Plug-Ins/Components/, the VST3 in /Library/Audio/Plug-Ins/VST3/ and the standalone app in /Applications/ — system-wide, for every user on the machine.

While the asset is still named crypta-vX.Y.Z-macos-unsigned.pkg, macOS will refuse to open it on a double-click; right-click the file and choose Open, then confirm. This applies to the installer only: the plugins it installs are signed with a Developer ID Application certificate, notarized and stapled, and load in a DAW without any warning. See issue #31.

macOS — manual

Prefer the .zip if you want the plugins in your own user folder rather than system-wide. Copy the bundles to:

Format	Path
AU (Component)	~/Library/Audio/Plug-Ins/Components/
VST3	~/Library/Audio/Plug-Ins/VST3/

If Logic Pro doesn't pick up the plugin after installing, force a rescan by resetting the AU cache:

killall -9 AudioComponentRegistrar
auval -a

Windows

Format	Path
VST3	C:\Program Files\Common Files\VST3\

Building from source

Requires JUCE 8.0.14, C++20, and CMake ≥ 3.24. See docs/building.md for full prerequisites and step-by-step build/test commands for macOS and Windows.

cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
cmake --build build
ctest --test-dir build --output-on-failure

Roadmap

Milestone	Description	Status
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	Deep-dive topology rebuild (2-band → 3-band) + presets & state recall — preset manager, 9 factory presets, state migration, German localisation	Done (v0.2.0)
M3	GUI & accessibility — custom vector LookAndFeel, full parameter surface, metering UI, resizable editor with stored scale, accessibility pass	Done
M4	Release: signing, notarization, v1.0.0 — installers, tagged release	Planned

License

Crypta is licensed under the GNU Affero General Public License v3.0 (AGPLv3).

This project uses JUCE 8, whose open-source tier is licensed under AGPLv3 (as of JUCE 8; JUCE 7 and earlier used GPLv3), which is why this project is AGPLv3 rather than GPLv3. See docs/adr/0002-agplv3-licensing.md for the full reasoning.

The editor embeds the EB Garamond typeface, licensed under the SIL Open Font License 1.1 — a copy of that licence ships with the source and inside the plugin's own resources.

VST is a registered trademark of Steinberg Media Technologies GmbH.

Crypta is an independent open-source project. It is not affiliated with, endorsed by, or sponsored by Neural DSP or the makers of any Parallax-branded product; any naming similarity refers only to the general "parallel bass processing" concept, not to any specific commercial product.

Releases

Tagged releases (v*) are built and published automatically by .github/workflows/release.yml — nothing is built or uploaded by hand. Release notes are the matching section of CHANGELOG.md.

• macOS — AU (.component), VST3 (.vst3) and Standalone, Universal Binary (arm64 + x86_64), signed with a Developer ID Application certificate (org-level secrets, shared across the Basilica Audio suite), notarized and stapled. Installs and opens without a Gatekeeper warning. Shipped both as a .zip of the three bundles and as a .pkg installer.
• Windows — VST3 and Standalone, unsigned. On first run, Windows SmartScreen may show a "Windows protected your PC" warning; choose More info, then Run anyway. Authenticode signing needs a paid certificate and is not part of this phase.
• Every asset is accompanied by a .sha256 checksum file.

The macOS .pkg itself is not yet signed, and its filename says so (…-macos-unsigned.pkg). Signing an installer requires a Developer ID Installer certificate — a different Apple certificate type from the application-signing one this repo already uses, and one that cannot be substituted by it. The bundles inside the installer are signed and notarized regardless, so only the installer wrapper needs a right-click → Open. See docs/building.md for the full release process, the secret names, and how the workflow switches to the signed path on its own once the certificate exists.

The latest published version is always on the Releases page.