4-Stage Allpass
Phase Rotation

Reduces crest factor by 2–4 dB through phase rotation of asymmetric waveforms — creating free headroom for compression, limiting, and shaping without changing perceived tonality.

How Phase Rotation Works

The Phase Rotator implements a cascaded 4-stage allpass filter network that progressively rotates the phase relationship between frequency components of the input signal. Allpass filters pass all frequencies at unity gain — they change nothing about the amplitude spectrum. What they do change is phase. By rotating the phase of asymmetric waveforms (voice, brass, kick drums — anything with unequal positive and negative peaks), the rotator redistributes energy more evenly across both polarities, reducing the peak-to-average ratio by 2–4 dB. The result: lower crest factor, identical perceived loudness, and measurably more headroom for every stage downstream.

  • Cascaded 4-stage allpass filter architecture
  • Unity gain across the entire frequency spectrum
  • Reduces peak-to-average ratio by 2–4 dB
  • Zero change to perceived loudness or tonal character
4-Stage Allpass Network
2–4 dB Crest Reduction
Zero Tonal Change
Free Headroom Created

Invisible Engineering

The Phase Rotator is one of the most elegant stages in the entire MixBus Platinum signal chain. It creates headroom from nothing, with zero sonic footprint. No listener will ever hear it working — but every downstream processor will feel its effect. The waveform enters asymmetric and exits symmetric, with identical spectral content and identical perceived loudness. It changes nothing the ear can detect but everything the math can measure. This is the kind of engineering that separates a serious broadcast processor from a chain of effects: invisible work that makes everything else sound better.

  • Completely transparent to the human ear
  • Waveform symmetry optimized without spectral alteration
  • Every downstream stage benefits from reduced crest factor
  • The hallmark of professional broadcast chain design
Phase Rotation · Crest Factor Reduction

The Headroom Multiplier

Every decibel of crest reduction the Phase Rotator achieves translates directly into one decibel less work for the lookahead limiter at Stage 10. That means less gain reduction, fewer artifacts, and a louder, cleaner final output at any given target level. Across 12 downstream stages — from the stereo enhancer through AGC, EQ, compression, shaping, and final limiting — the compounding benefit of 2–4 dB of free headroom is substantial. The compressor can be driven harder without distortion. The limiter activates less frequently. The shaper operates in a more linear region. All because Stage 3 did its job invisibly.

  • 1 dB of crest reduction = 1 dB less limiter work
  • Compressor can be driven harder without distortion
  • Shaper operates in a more linear, musical region
  • Compounding benefit across the entire processing chain
12 Downstream Stages Benefit
Transparent Sonic Character
Program Dependent
Automatic No Controls Needed

Experience Phase Rotation in
MixBus Platinum

The headroom you didn't know you had — extracted automatically, with zero sonic compromise.

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