PHIXER for Piano: stereo / spaced-pair phase that keeps body on mono fold
Grand and upright captures stack risk: spaced L/R pairs, lid or high mics, XY or ORTF plus a hammer spot, sometimes a room or pedal board. In headphones the piano feels wide and alive. On phone playback, Bluetooth, or livestream mono, low-mid body thins and hammer attack cancels. Polarity and timing come first. Free phase-repair helps after residual L/R fights remain on a stereo piano print you must keep stereo. It is not a piano tuner, and it does not replace a true mono listen on the bus.
Download PHIXER free YouTube tutorial
PHIXER is free stereo phase-repair (VST3/CLAP/AU · Win/Mac/Linux) from Riverflux Audio. Frequency-aware phase rotation for leftover L/R fights on stereo material. It is not a pitch corrector, not a reverb, not a widener, and not a substitute for mic placement. Use it after hygiene, when residual spectral cancellation remains on a stereo bed you must keep stereo.
Three piano failure modes this page covers
- Spaced-pair / stereo piano phase. Fine in cans; thin on phone or mono fold. Full checklist: Piano stereo / spaced-pair phase.
- Choir / ensemble cousin. Spots vs mains that cancel on stream mono. Cousin guide: PHIXER for Choir.
- Electric piano / Rhodes cousin. Multi-mic EP beds that hollow on fold. Cousin guide: Electric piano / Rhodes phase.
Fast piano mono audition (about 60 seconds)
- Sum L+R on the piano bus or master (or monitor controller mono). Listen to low-mid body, hammer attack, and pedal wash.
- A/B stereo vs mono. Note what disappears: chest of chords, left-hand weight, stereo width that was actually cancellation.
- Mute lid vs spaced pair briefly. Mute hammer spot vs main pair. Note which path thins the fold.
- Confirm on a phone speaker or single earbud path, then again after any bus compressor / EQ pass, not only before cleanup.
Honest order of fixes (before spectral phase rotation)
1. True mono listen on the piano / program bus
Hard L+R sum or monitor mono. Habit: piano stereo checklist and mono check workflow.
2. Mic placement and hero path before plugins
Prefer one clear main pair for body. Spots for hammers and detail, not as a second stereo width layer that fights the mains.
3. Polarity if a path flips
Inverted lid channel, reversed spaced mic, mid-side decode mistakes. Flip Ø when body returns. Guide: polarity vs phase.
4. Timing / delay-align before spectral tools
Lid or spots farther than the main pair need a few ms, not a widener. Prefer aligning to the hero pair for critical lows.
5. Only then audition residual L/R spectral fights
If a stereo piano bed must stay stereo and fold still hollows a band after the steps above, gentle frequency-aware phase rotation can help. Prove it with mono A/B. Watch the YouTube tutorial and the mono demo.
Piano path types
| Setup | Common mono failure | First fix |
|---|---|---|
| Spaced L/R over the harp | Body dips when summed | Polarity; check spacing; mono listen |
| Lid / high mic + main pair | Hammer or lid path thins fold | Align; mute test; prefer hero pair |
| XY / ORTF + hammer spot | Attack cancels on phone | Align spot; polarity; piano checklist |
| Upright close + room | Width hollows on Bluetooth | Mono listen; quieter room path |
| Choir / ensemble cousin | Spots vs mains cancel on stream | Choir guide |
| Rhodes / EP multi-mic cousin | Amp + DI fights on fold | EP / Rhodes guide |
Choir cousin (short version)
- Spots vs mains on a choir bed create the same mono-fold shape as lid vs spaced pair on a piano bed.
- Sync and polarity still come first. Spectral tools after residual L/R fights only.
- Full write-up: PHIXER for Choir.
When not to reach for PHIXER
- Wrong polarity on a lid or spaced mic (flip Ø first).
- Spot late vs main pair by several ms (align timing first).
- You only need a true mono print from one hero pair (print mono; do not fake stereo width).
- Tuning or pedaling issues that are not L/R cancellation.
- Honesty list: When not to use PHIXER.