DecayChain

Overview

DecayChain is a modern bit-crusher and wavetable distortion plugin that puts a preamp/tone stage up front and offers flexible bit logic either before or after a wavetable mapper loaded with 265 original procedurally generated wavetables.

The signal path flows from a soft-clipping preamp through a tilt EQ, sample-rate reducer, bit section, wavetable mapper with smooth morph between adjacent tables, dry/wet mix, optional safety low-pass filter, and output trim. Envelope routing lets you modulate the SRR frequency and bit depth dynamically.

DecayChain supports two DSP processing modes:

• Legacy — the original processing path. Wavetable lookup uses nearest-sample indexing for a deliberately crunchy, lo-fi character. The bit crusher and wavetable stages operate directly on each sample with no anti-aliasing.
• ADAA — Antiderivative Anti-Aliasing for cleaner harmonics with reduced aliasing artifacts at the base sample rate, combining Simpson's rule ADAA on the bit crusher and LUT integral ADAA on the wavetable mapper.

Signal Path

Audio flows through a carefully staged chain designed for maximum tonal flexibility:

1. Input — incoming audio signal
2. Preamp — ±36 dB gain with soft-clip guard at extremes
3. Tone — tilt EQ at 800 Hz, true bypass when centred
4. Pre HP — pre high-pass filter (20 Hz – 5 kHz)
5. Pre LP — pre low-pass filter (1 kHz – 20 kHz)
6. SRR — sample-rate reducer (~260 Hz → 192 kHz), with optional Fine mode
7. Bit Section — 1–16 bit depth or 0–255 hex bitmask, pre or post wavetable
8. Wavetable Mapper — 265 × 256-point tables, hex index 00–108
9. Morph — smooth blend toward adjacent table (0.0–1.0)
10. Table Mix — wavetable stage dry/wet blend (0–100%)
11. Dry/Wet Mix — equal-power crossfade
12. Safety LPF — optional post-processing low-pass filter
13. Output Trim — −24 to +12 dB final level control

Key Features

• Dual Bit-Crush Modes: Standard bit-depth reduction (1–16 bits) for classic staircase quantisation, or hex bitmask mode (0–255) for XOR-like logic patterns and unusual harmonic textures.
• Pre/Post Bit Placement: Run the bit section before the wavetable for crushed-then-shaped tones, or after for shaped-then-crushed results. Each ordering produces fundamentally different distortion character.
• 265 Original Wavetables: All procedurally generated (256 samples each, float32), embedded via BinaryData with no external files. Hex index display (00–108) for precise table selection.
• Smooth Table Morph: Blend seamlessly between adjacent wavetables for evolving timbral transitions. In ADAA mode, anti-aliasing is evaluated independently on both tables and linearly blended.
• Envelope Routing: Route an internal envelope to the sample-rate reducer, bit depth, or both, with bipolar modulation amounts (−1 to +1) for dynamic, input-responsive distortion.
• Dual DSP Modes: Legacy mode for raw, crunchy lo-fi character. ADAA mode combines Simpson's rule on the bit crusher and LUT integral anti-aliasing on the wavetable mapper.
• Pre Filters: Adjustable high-pass (20 Hz – 5 kHz) and low-pass (1 kHz – 20 kHz) for sculpting the input signal before the crush stages.
• Preamp & Tone Stage: ±36 dB preamp with soft-clipping drives the downstream distortion stages. Tilt EQ at 800 Hz shapes the input spectrum before crushing.
• Safety LPF: Optional first-order low-pass (18 kHz default) tames harsh upper harmonics when needed, without affecting the core distortion character.
• Zero-Latency Processing: No latency added to your signal chain. Zero heap allocations on the audio thread, denormal/NaN guards on every nonlinear boundary.
• 21 Factory Presets: From lo-fi samplers and industrial drones to ambient shimmer and bass destruction — with full user preset management.

Controls

Factory Presets

DecayChain ships with 21 factory presets across a wide range of styles.

User presets are stored as .nfapreset files in:

• macOS: ~/Library/Application Support/Nullform Audio/DecayChain/Presets/
• Windows: %APPDATA%\Nullform Audio\DecayChain\Presets\

Plugin Formats & Compatibility

Compatible with any VST3- or AU-compatible DAW including Logic Pro, Ableton Live, Reaper, Studio One, Cubase, FL Studio, Bitwig, and more.

System Requirements

macOS

• macOS 10.15 (Catalina) or later
• 64-bit Intel or Apple Silicon (Universal Binary)
• 4 GB RAM (8 GB recommended)
• ~50 MB free disk space
• Screen resolution of 1280 × 720 or higher

Windows

• Windows 10 or later (64-bit)
• 4 GB RAM (8 GB recommended)
• ~50 MB free disk space
• Screen resolution of 1280 × 720 or higher

Installation

macOS

The macOS release is a signed and notarised .pkg installer.

1. Download DecayChain-<version>.pkg from the release page.
2. Double-click the .pkg file to launch the installer.
3. Follow the on-screen prompts. The installer places:
   • VST3 plug-in → /Library/Audio/Plug-Ins/VST3/
   • AU plug-in → /Library/Audio/Plug-Ins/Components/
   • Factory Presets → /Library/Application Support/Nullform Audio/DecayChain/Presets/Factory/
4. Open your DAW and scan for new plug-ins. DecayChain will appear under Nullform Audio.

Windows

The Windows release is an Inno Setup .exe installer.

1. Download DecayChain-<version>-Windows.exe from the release page.
2. Run the installer. If Windows SmartScreen appears, click More info → Run anyway.
3. Choose the installation type:
   • Full — VST3 + Factory Presets (default)
   • VST3 only — plug-in without presets
   • Custom — choose individually
4. Open your DAW and scan for new plug-ins. DecayChain will appear under Nullform Audio.

Uninstalling

macOS: Remove the following items:

• /Library/Audio/Plug-Ins/VST3/DecayChain.vst3
• /Library/Audio/Plug-Ins/Components/DecayChain.component
• /Library/Application Support/Nullform Audio/DecayChain/

Windows: Use Add/Remove Programs (Settings → Apps). The uninstaller removes the VST3 plug-in and factory presets. User presets in %APPDATA% are not touched.