Marimba, vibraphone, xylophone, and mallet multi-mic phase: close bars vs OH/room fold
Close bar mics on marimba, vibraphone, xylophone, and other mallets feel huge in headphones. On stem, phone, broadcast, or archival mono fold, fundamental tone and mid bloom often thin or cancel against OH and room paths that carry the same bars a few milliseconds later. That is usually polarity and arrival time between closes and OH/room, plus a stereo mallet 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 mallet beds before mono fold.
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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 mallet compressor, not a widener, and not a substitute for gain structure or mono audition of the stem or delivery bus. Polarity and timing first; PHIXER after residual spectral fights.
What mallet multi-mic phase failure sounds like
- Fundamental tone thins when OH opens under closes. Close bars and OH share the same attack a few ms apart.
- Vibe motor / shimmer huge in cans, hollow on phone. Close + room cancel mid bloom on fold.
- Xylophone bite fights the room. Same bars twice with different delay.
- Stereo spaced pair collapses on stem fold. Hard L/R low/high bar layouts disappear when the platform folds.
- Fine in cans, broken on phone / broadcast / stem delivery. Same destinations as percussion / hand drums, overhead & room, YouTube / social, and broadcast.
Fast mono audition (about 60 seconds)
- Solo the stem / mix / delivery bus (not only headphones). Flip a utility to mono.
- A/B closes muted vs open under OH/room. Note what disappears: fundamental, mid bloom, attack bite, vibe shimmer.
- Solo pairs: close bars vs OH, close vs room, stereo pair vs mono fold, library close/room/OH if layered.
- Check correlation on the delivery bus, then with closes muted vs full (correlation meters).
Order of operations (before spectral phase rotation)
1. Polarity between close bars and OH / room
Flip closes vs OH, or closes vs room, when fundamental tone or mid bloom returns immediately. Guide: polarity vs phase. Related percussion habit: percussion / hand drums.
2. Small delay align closes to the OH / room
Close bar mics arrive earlier than OH or room. A few samples of delay on closes (or nudge to the hero OH) often restores tone better than any widener. Different job from spectral repair.
3. One hero mallet image to the stem or mix
Do not send every close, OH, and room path all hot into the stem or mix bus. Pick a hero image (often OH/room or a balanced stereo pair), keep extras muted or low. Parallel stacks are classic hollow-tone on phone fold. Related: overhead & room, orchestral spot vs section.
4. Prefer OH/room as the body; quieter close color
Closes should color attack and register detail, not replace the OH for the mix. If every close sits at full level under loud OH, mono fold almost always hollows fundamental. Pull closes first.
5. Skip wideners and Haas on mallet beds before fold
Short-delay width and stereo imagers make headphones huge and phones hollow. Keep critical fundamental centered for stem and broadcast.
6. Only then audition residual L/R spectral fights
If a stereo mallet 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 |
|---|---|---|
| Close bars + OH | Fundamental / mid tone cancel on fold | Polarity; delay closes; quieter closes |
| Close bars + room | Bloom disappears on phone / stem | Polarity + delay; hero room or OH |
| Vibe close + motor spill under OH | Shimmer hollows or combs | Pull close; polarity |
| Stereo spaced pair hard L/R | Huge in cans, gone on phone | Center critical lows; simplify width |
| Library close + room + OH all hot | Sample stack cancels on stem | One hero mic position; mute extras |
| Stem / broadcast print | Fine in suite, hollow on air | Broadcast mono check |
Mallet stem / mix checklist (to print)
1. Label close vs OH vs room paths
Name close bars, OH, and room so mixers know what hits the stem or delivery. Ambiguous stacks get left open and comb on fold.
2. Mono-check delivery bus alone, then with full mallets
Solo low bars in mono. Then open mid/high registers in mono. Note fights between close color and OH body. Related: percussion / hand drums.
3. Watch phone and social destinations
Most listeners hear mono or near-mono. Guides: YouTube / social, master bus mono.
4. Optional correlation check before print
Host-agnostic habit: correlation meters, master bus mono checklist.
When PHIXER belongs on mallet-related stereo
- The material is already stereo and must stay stereo (stereo OH pair, 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 fundamental or bloom without wrecking the image.
- You are not using it to "fix" unaligned close+OH under room, or to replace a time-align edit on the stem.
Decision table
| You notice… | First try | Why |
|---|---|---|
| Tone thins when OH opens under closes | Polarity; delay closes; quieter closes | Arrival-time fight |
| Closes + room collapse on stem | Hero OH/room; polarity; delay | Stacked identical content |
| Fine in cans, thin on phone | Mono delivery bus; pull closes | Cans ≠ listener fold |
| Stereo mallet still cancels by band | PHIXER on that stereo bed | Residual spectral L/R fight |
| Mono close 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 stem / mix / delivery bus yet.
- The fix is obviously polarity, delay, one hero mallet image, or quieter closes under OH/room.
- You want PHIXER to make the mallets louder, wider, or "more concert hall." 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 close bars vs OH/room → delay-align closes → one hero mallet image → quieter closes under hero OH/room → skip Haas/imagers → mono-check with full registers → PHIXER only for leftover stereo cancellation on a mallet bed → fold again for stem / phone / broadcast.