Signal Flow

The Signal Chain

Default Order: INPUT → EQ → Multiband → Compressor → Limiter → OUTPUT

Analysis Taps

These taps read the signal at different points in the chain for display only — they run in parallel and don't affect the audio.

• Pre-EQ spectrum tap — FFT, 512 log-spaced bins, feeds the spectrum analyzer
• Post-EQ spectrum tap — same, shows the shaped signal after EQ
• Post-dynamics spectrum tap — same, after the last dynamics module (purple overlay)
• LUFS meter — ITU-R BS.1770-4 loudness measurement, parallel tap from output

Stereo Metering Taps

• Input stereo meters — FFT 256, L/R peak and RMS after input gain
• Output stereo meters — FFT 256, L/R peak and RMS after the limiter
• Read at ~30 fps, 256 samples per channel

Fixed vs. Draggable Modules

Fixed Modules (Always Same Position)

• INPUT: Must be first - normalizes incoming audio, removes DC offset, provides analysis taps
• LIMITER: Must be after dynamics - catches peaks from compression makeup gain, prevents clipping
• OUTPUT: Must be last - final gain control, LUFS measurement before destination

Draggable Modules (Reorderable)

• EQ: Frequency shaping with Linear Phase or M/S modes
• MULTIBAND: Frequency-dependent dynamics (3 or 4 bands)
• COMP: Full-band compression with sidechain filtering

How to reorder: Click and drag a module block's drag handle (three horizontal lines). Drop between connectors to change position. Module order is saved in presets and site overrides.

Why Order Matters

Different module orders create fundamentally different sounds. Here's why:

EQ Before Compression

Order: INPUT → EQ → COMP → LIMIT → OUTPUT

• What happens: You shape the frequency balance, THEN compress the shaped audio
• Result: Compressor reacts to post-EQ signal. Boosted frequencies trigger more compression.
• Use for: Corrective listening — fix frequency issues before leveling dynamics
• Example: Cut muddy 200Hz, then compress. Compressor won't pump from bass anymore.

Compression Before EQ

Order: INPUT → COMP → EQ → LIMIT → OUTPUT

• What happens: You level dynamics first, THEN shape tone
• Result: EQ doesn't affect compressor behavior. Cleaner separation of dynamics and tone.
• Use for: When you want compression to be frequency-agnostic
• Example: Compress evenly, then boost presence at 3kHz without changing compression behavior.

Multiband First

Order: INPUT → MB → EQ → COMP → LIMIT → OUTPUT

• What happens: Frequency-dependent dynamics control, then tonal shaping, then final glue
• Result: Multiband tames problem frequencies, EQ shapes overall tone, compressor glues it together
• Use for: Taming problem frequencies before shaping tone
• Example: De-ess with multiband (5-8kHz), EQ for warmth, final compression for consistency.

Drag-and-Drop Reordering

How It Works

1. Click and hold the drag handle (three horizontal lines) on any draggable module
2. Drag the module left or right
3. Visual feedback:
   • Dragged module becomes semi-transparent
   • Valid drop zones (connectors) highlight in green
   • Invalid drop zones (adjacent to current position) dim
   • Other modules shift to make room
4. Drop on a connector to reorder
5. Audio crossfades to new order (50ms, glitch-free)

Bypass Arcs

When a module is bypassed, an orange arc appears showing signal routing around it:

• Single bypass: U-shaped arc over one module
• Consecutive bypasses: Arc spans all bypassed modules in sequence
• Signal flows through bypass path, module processing is skipped (saves CPU)

Analysis Tap Points

TabDSP has multiple analysis taps that measure audio at different points in the signal chain. These run in parallel and don't affect the audio signal.

State Persistence

Module order and bypass states are saved in:

• Global settings: Applies to all websites by default
• Site overrides: Per-website settings (enable "Site Override" toggle)
• Presets: Saved in custom and factory presets
• A/B comparison: Module order switches when toggling A/B

State format:

{
  moduleOrder: ['eq', 'multiband', 'singleComp'],
  moduleBypass: {
    eq: false,
    multiband: true,   // Bypassed
    singleComp: false
  }
}