Accordion / bandoneon / concertina multi-mic phase: left/right manuals vs room fold
Left and right manual mics (or dual grille mics) feel wide and rich in the booth and on stage monitors. On studio mono fold, tango PA, or livestream, body and bellows often thin or cancel against room and OH paths that carry the same instrument a few milliseconds later. That is usually polarity and arrival time between manuals and room, plus a stereo accordion bed that was never folded before send. Fix polarity and small delays first. Frequency-aware phase repair belongs only after residual L/R fights remain on stereo accordion beds before mono fold.
Download PHIXER free PHIXER hub
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 an accordion compressor, not a widener, and not a substitute for mic placement or mono audition of the stream or PA bus. Polarity and timing first; PHIXER after residual spectral fights.
What accordion / bandoneon phase failure sounds like
- Body and bass side thin on livestream. Left/right manuals and room share the same energy a few ms apart.
- Bellows and treble huge in booth, hollow on phone. Hard L/R manual layouts disappear when the platform folds.
- Room mic fights dual grille closes. Same content twice with different delay into the matrix.
- Stage PA or tango fold cancels midrange reed. Stereo bed never checked in mono before send.
- Fine in cans / monitors, broken for remote viewers. Same destinations as club / DJ / PA, live FOH / foldback, OBS livestream.
Fast mono audition (about 60 seconds)
- Solo the stream / PA / mix bus (not only booth headphones). Flip a utility to mono.
- A/B left/right manuals muted vs open under room/OH. Note what disappears: body, bass side, bellows, reed attack.
- Solo pairs: L vs R manuals, closes vs room, stereo accordion bed vs mono fold.
- Check correlation on the delivery bus, then with accordion muted vs full.
Order of operations (before spectral phase rotation)
1. Polarity between manuals and room / OH
Flip left vs right, or closes vs room, when body or bass side return immediately. Guide: polarity vs phase. Related: piano stereo, pipe organ.
2. Small delay align closes to the room / hero image
Manual and grille mics often arrive earlier than room or OH. A few samples of delay on closes (or nudge to the hero room image) often restores body better than any widener.
3. One hero accordion image to the stream or PA bus
Do not send every left, right, room, and OH path all hot into the livestream or PA. Pick a hero image (often a balanced L/R pair or a focused close+room blend), keep extras muted or low. Parallel stacks are classic hollow-body on phone fold. Related: overhead & room.
4. Prefer hero room or balanced pair as the body; quieter color extras
Extra spots should color reed detail, not replace the hero image for the stream mix. If every close sits at full level under loud room, mono fold almost always hollows body. Pull extras first.
5. Skip wideners and Haas on accordion beds before fold
Short-delay width and stereo imagers make booth headphones huge and phones hollow. Keep critical low end and bass side centered for stream and PA.
6. Only then audition residual L/R spectral fights
If a stereo accordion 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, rotator bypassed vs engaged.
Path types and typical failure modes
| Path | Common mono failure | First fix |
|---|---|---|
| Left + right manuals | Body / bass side cancel on stream | Polarity; delay; simplify width |
| Closes + room / OH | Bellows / reed disappears on phone | Polarity + delay; hero image |
| Bandoneon + ensemble bleed | Attack combs or thins | Bleed control; polarity; one hero |
| Stereo pair hard L/R | Huge in cans, gone on phone | Center critical lows; simplify width |
| FOH / matrix → OBS / PA | Fine in booth, hollow for crowd | OBS livestream / club PA |
Studio / stage / livestream checklist (to send)
1. Label left vs right vs room vs OH paths
Name manuals, grille closes, room, and OH so operators know what hits the livestream or PA. Ambiguous stacks get left open and comb on fold.
2. Mono-check delivery bus alone, then with full accordion
Solo body and bass side in mono. Then open bellows and reed attack in mono. Note fights between close color and hero body.
3. Watch phone, social, and PA destinations
Most remote viewers and many dancers hear mono or near-mono. Guides: live FOH, club / PA.
4. Optional null / mono workflow before show
Host-agnostic habit before you go live or print: master bus mono checklist.
When PHIXER belongs on accordion-related stereo
- The material is already stereo and must stay stereo (stereo L/R manuals, stereo room print), not a mono close you fake-widened.
- Polarity, delay align, and hero-path levels are cleaned up, but fold still hollows a band of the spectrum.
- You can A/B mono with the plugin bypassed and hear clearer body or bellows without wrecking the image.
- You are not using it to "fix" unaligned L/R under room, or to replace a time-align edit on the matrix.
Decision table
| You notice… | First try | Why |
|---|---|---|
| Body thins when room opens under manuals | Polarity; delay closes; quieter closes | Arrival-time fight |
| Bellows + room collapse on stream | Hero image; polarity; delay | Stacked identical content |
| Fine in booth, thin on phone | Mono delivery bus; pull extras | Booth ≠ viewer fold |
| Stereo accordion still cancels by band | PHIXER on that stereo bed | Residual spectral L/R fight |
| Mono accordion alone is dull | Tone / EQ / gain / mic choice | Not an L/R repair job |
When NOT to use PHIXER here
- You have not mono-auditioned the stream / PA / mix bus yet.
- The fix is obviously polarity, delay, one hero accordion image, or quieter closes under room.
- You want PHIXER to make the accordion louder, wider, or "more tango." Wrong job.
- The path is mono and the print problem is balance or EQ.
- See also when not to use PHIXER.
Quick path: Solo delivery bus in mono → polarity L/R manuals vs room/OH → delay-align closes → one hero accordion image → quieter extras under hero → skip Haas/imagers → mono-check with full accordion → PHIXER only for leftover stereo cancellation on an accordion bed → fold again for stream / PA / stage send.
Related guides
- Piano stereo / spaced-pair phase
- Pipe organ / church organ multi-mic + room phase
- Bluegrass / acoustic string-band multi-mic phase
- Steelpan / steel drum multi-mic phase
- Overhead & room mic phase
- Polarity vs phase rotation
- When not to use PHIXER
- Club / DJ / PA mono fold
- Live FOH / foldback / stream phase