IR Export Windowing vs DSP Correction

In CamillaFIR, IR export windowing and DSP correction are intentionally treated as two separate stages. This separation is fundamental for clarity, reproducibility, and meaningful A/B comparisons.

DSP Correction (what is corrected)

The actual correction logic operates during analysis and optimization, before any FIR is written to disk. This stage defines what is corrected and by how much, including:

  • target curve fitting
  • magnitude correction
  • phase / excess-phase reconstruction
  • FDW / Adaptive FDW (A-FDW)
  • Temporal Decay Control (TDC)
  • auto-leveling and safety limits

These processes determine the final frequency- and phase-domain behavior of the correction. They are not affected by IR export windowing.

IR Export Windowing (how the FIR is written)

IR export windowing affects only the time-domain representation of the exported FIR impulse.

REW-style windowing:

  • reshapes the impulse response in the time domain
  • affects onset delay, symmetry, and tail behavior
  • does not change the underlying frequency or phase response of the FIR

Supported modes (UI):

  • auto - automatic window selection (default)
  • rew_asym - REW-style asymmetric (causal) window

Legacy config values (off, rew_sym) are still accepted when set directly in config files, but are no longer exposed in the UI.

Why this distinction matters

The same DSP correction can legitimately produce multiple FIR files that share:

  • identical frequency response
  • identical phase response

but differ in:

  • time alignment
  • impulse symmetry
  • practical latency characteristics

This is useful for:

  • matching different convolver requirements
  • minimizing audible latency
  • comparing results directly with REW
  • controlled listening tests and A/B evaluation

For this reason, CamillaFIR:

  • keeps DSP correction deterministic and invariant
  • allows IR export windowing as a separate, explicit choice
  • includes the windowing type in exported filenames for traceability

In short:
DSP correction defines the filter behavior.
IR export windowing defines how that behavior is packaged in time.

Disclaimer

AI was used to translate this document from Finnish to English.