TabDSP Modules
TabDSP's signal chain consists of six processing modules. Three are reorderable via drag-and-drop (EQ, Multiband, Compressor), while three are fixed (Input, Limiter, Output).
Signal Flow
Default order - EQ, MB, and COMP can be reordered via drag-and-drop
Processing Modules
Input Gain
Fixed FirstControl input level before processing. Normalize hot or quiet sources for optimal gain staging through the signal chain.
- Range: -24 to +24 dB
- Visual input meter with peak hold
- Knob control in module block
- Essential for proper compressor behavior
Graphic EQ
Reorderable8-band parametric EQ with real-time spectrum analyzer. Surgical frequency shaping with Linear Phase mode and M/S processing.
- 512-bin constant-Q spectrum (AnalyserNode FFT 8192)
- Bell, Low Shelf, High Shelf filter types
- HP/LP filters: 12-48 dB/oct slopes
- Digital, Analog, Linear Phase, M/S modes
Multiband Compressor
ReorderableFrequency-dependent dynamics with 3 or 4 bands. Linkwitz-Riley crossovers ensure phase coherence. Perfect for taming harshness without affecting the whole mix.
- LR4 (24dB/oct) crossover network
- Per-band threshold, ratio, attack, release
- Draggable crossover frequencies on spectrum
- Real-time per-band gain reduction meters
Single-Band Compressor
ReorderableClassic full-band dynamics with true sidechain high-pass filtering. RMS or peak detection for musical or transparent compression.
- RMS envelope follower with soft knee
- True sidechain HP filter (20-300 Hz)
- Ratios: 1:1 to 20:1
- Waveform visualization: GR, input, output
True Peak Limiter
Fixed (before Output)Broadcast-compliant brickwall limiting with 4x polyphase oversampling. Prevents inter-sample peaks that clip on consumer devices.
- ITU-R BS.1770-4 true peak detection
- 15 compliance presets (EBU R128, Apple Music, etc.)
- Lookahead (0.5-10ms) and release control
- Kaiser or ITU filter modes
Master Gain
Fixed LastFinal output level control after all processing. Adjust overall loudness without changing processing balance.
- Range: -24 to +24 dB
- Post-limiter, pre-output
- Knob control in module block
- Does not affect LUFS measurement
Key Concepts
Fixed vs. Reorderable Modules
Fixed modules always stay in the same position:
- INPUT: Must be first to normalize incoming audio
- LIMITER: Must be after dynamics to catch peaks from makeup gain
- OUTPUT: Must be last for final level control
Reorderable modules can be dragged to change signal flow:
- EQ, MULTIBAND, COMP: Drag module blocks to reorder
- Order affects sound (e.g., EQ before compression vs. compression before EQ)
- 50ms crossfade prevents glitches during reordering
Bypass vs. Disable
Bypass: Signal routes around module (no processing, no CPU usage)
- Click power icon on module block
- Orange arc shows signal routing around bypassed module
- "BYPASSED" overlay on canvas
- Module parameters preserved for later
Disable (Global): All processing off
- Uncheck "Enabled" at top of popup
- Audio passes through unprocessed
- Stops all CPU usage
Module Order Matters
Different orders create different sounds. Common patterns:
| Order | Use Case | Why It Works |
|---|---|---|
| EQ → MB → COMP | Mastering (default) | Shape frequencies, control per-band dynamics, glue with compression |
| COMP → EQ → MB | Parallel-style mixing | Control dynamics first, then shape tone without compression artifacts |
| MB → EQ → COMP | Broadcast/podcast | Tame sibilance (multiband), surgical EQ, final glue compression |
| EQ → COMP → MB | Vocal processing | Remove mud (EQ), even out dynamics (comp), de-ess (multiband) |