Riverflux Audio · Practical · Polarity invert vs phase rotation
Polarity invert vs continuous phase rotation
A polarity flip is a 180 invert. Continuous phase rotation is a different job. Flip first when one path is simply upside down. Reach for frequency-aware rotation (PHIXER) only when leftover L/R spectral fights still scoop bass after invert and timing, and you must keep the bed stereo.
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PHIXER is free stereo phase-repair (VST3/CLAP/AU · Win/Mac/Linux) from Riverflux Audio. Continuous, frequency-aware phase rotation for residual L/R cancellation on stereo material. It is not a polarity switch, not a time-align delay, not a Haas widener, and not an M/S encoder. Use it after hygiene, when mono fold still hollows a band you care about.
When a polarity flip fixes it
- Dual mic / DI + cab. One path is wired or routed inverted. Flip Ø and kick or bass body returns fully on mono sum.
- Overheads vs snare bottom. Classic 180 mismatch. Invert restores crack and body together.
- Parallel bus copy. A send path got inverted relative to the dry. Flip restores punch instead of cancel.
- Tell. After one Ø flip, phone / club / livestream mono sounds solid across the spectrum. Stop. You did not need rotation.
When you need continuous phase rotation (PHIXER)
- Invert helps only part of the spectrum. Low end returns, mid still scoops on fold (or the reverse).
- Stereo bed you must keep stereo. Pads, stereo guitars, sample beds, room pairs that cannot collapse to mono print.
- Timing already checked. A few samples of attack align did not clear the residual band fight.
- Not Haas, not M/S first aid alone. Fake delay width and mid/side hygiene are cousins; see Haas width vs phase and mid/side vs phase rotation.
60-second decision order
- True L+R mono sum (or classic invert-null). Habit card: null-test + polarity checklist.
- Flip Ø on one path. Keep the flip that returns body. If mono is solid, stop.
- Nudge a few samples of attack timing if the transient still smears. Invert cannot slide time.
- Only then audition continuous phase rotation on the stereo bed you must keep stereo. A/B mono before and after.
- If a mono-safe center print is enough, print mono and skip spectral tools. Honesty: when not to use PHIXER.
Invert vs rotation at a glance
| Symptom | Likely fix | Reach for PHIXER? |
|---|---|---|
| Whole low end returns after one Ø flip | Polarity invert | No |
| Attack smears after Ø | Sample timing / time-align | No (not yet) |
| Width from short delay collapses in mono | Kill or tame Haas copy | Only to check leftovers. Haas guide |
| M/S width thins fold but mid is fine | M/S hygiene first | Maybe after. M/S vs phase |
| Invert + timing done; one band still cancels on stereo bed | Continuous phase rotation | Yes, gentle A/B |
Related guides
- Null test + polarity checklist (invert vs continuous rotation)
- Haas delay width tricks vs true phase issues
- Mid/side processing vs stereo phase rotation
- Stereo imager vs phase repair
- Polarity vs phase (compare)
- Phase repair vs time align
- Free polarity tools vs time-align vs PHIXER
- When not to use PHIXER
- PHIXER for Bus Sidechain / heavy bus compression and sidechain stereo phase
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