Foley, prop, and SFX multi-mic phase: when close + room (or lav+boom style) cancel body or bite in mono
Footsteps, cloth, props, and designed SFX often ride a close mic under a room mic, or a lav-style spot under a boom-style room. Soloed, the detail is crisp. On mono fold for phone, broadcast, stem delivery, or LoRo, the body thins or the transient bite collapses. That is usually polarity and arrival time between close and room paths, not a missing widener. Fix polarity and small delays first. Frequency-aware phase repair belongs only after residual L/R fights remain on stereo SFX material.
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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 foley library, not a time-aligner for every prop take, and not a substitute for mono audition of the SFX bus. Polarity and timing first; PHIXER after residual spectral fights.
What foley / SFX phase failure sounds like
- Close prop huge alone, thin under room. Detail cancels body when the room opens.
- Footstep transient disappears on mono fold. Close and room share the attack a few milliseconds apart.
- Lav-style spot + boom-style room hollow cloth or handle noise. Same lav+boom habit as dialogue, applied to SFX.
- Library close + room layers at unity. Stacked identical content without a mono check.
- Fine in headphones, broken on phone / TV / LoRo. Same destinations as film LoRo, broadcast, and social fold.
Fast mono audition (about 60 seconds)
- Solo the foley / SFX bus (or one prop group). Flip the master (or a utility) to mono.
- A/B close muted vs open under the room. Note what disappears: body, transient bite, cloth detail.
- Solo pairs: close vs room, lav-style vs boom-style, library close vs room layer. Find which pair collapses.
- Check correlation on the SFX bus, then on the mix bus with SFX muted vs unmuted (correlation meters).
Order of operations (before spectral phase rotation)
1. Polarity between close and room
Flip close vs room when body or bite returns immediately. Guide: polarity vs phase. Related outdoor habit: field / lav+boom.
2. Small delay align close to the room
Close mics arrive earlier than room or boom-style paths. A few samples of delay on close (or nudge to the room) often restores body better than any widener. Different job from spectral repair: vs time-align.
3. Prefer one hero image per prop
Close should detail; room should space. If both sit at full level, mono fold almost always hollows. Pull one down, or mute the weaker path for that cue.
4. Simplify library multi-mic / layered one-shots
Close/room/OH library layers at unity are a classic body killer. Mute unused layers, or prefer one hero. Guides: sample library, sample stacks.
5. Skip Haas and imagers on transient SFX
Short-delay width makes headphones huge and phones hollow on footsteps and props. Guides: vs imagers, Haas vs phase repair.
6. Only then audition residual L/R spectral fights
If a stereo room bed or stereo designed SFX 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.
Path types and typical failure modes
| Path | Common mono failure | First fix |
|---|---|---|
| Close prop + room mic | Body or transient cancel when both open | Polarity + delay close to room; quieter close |
| Lav-style + boom-style SFX | Detail hollows on fold | Polarity; one hero level; related field |
| Footsteps close + room | Attack disappears on phone / TV | Delay align; prefer one hero |
| Library close + room layers | Hollow on stem delivery | Mute unused; sample stacks |
| SFX stem vs dialogue stem | Presence drop when stems sum | Stem delivery mono sum |
| TV / streaming / LoRo print | Fine in suite, hollow on air / phone | LoRo · Broadcast |
Foley / SFX delivery checklist
1. Label close vs room vs designed layers
Name tracks so editorial knows which paths are close and which are room. Ambiguous stacks get left open and comb on fold.
2. Mono-check SFX alone, then with dialogue
Solo foley/SFX in mono. Then open dialogue and music in mono. Note fights between stems. Related: dialogue / ADR.
3. Watch stem and LoRo destinations
SFX often live as a stem. Guides: stem bus, LoRo, game audio mono.
4. Optional null / mono workflow in the DAW
Host-agnostic habit before you ship: DAW null-test + mono-check.
When PHIXER belongs on foley / SFX stereo
- The material is already stereo and must stay stereo (stereo room bed, stereo designed SFX, stereo library print), not a mono close you fake-widened.
- Polarity, delay align, and one-hero level 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 without wrecking the image.
- You are not using it to "fix" unaligned close under room, or to replace a time-align edit.
Decision table
| You notice… | First try | Why |
|---|---|---|
| Close + room hollow body / bite | Polarity; delay close; quieter close | Arrival-time fight |
| Only library layers collapse | Mute unused; one hero | Stacked identical content |
| SFX fine alone, thin vs dialogue | Stem mono sum; balance | Cross-stem fight |
| Stereo room still cancels by band | PHIXER on that stereo bed | Residual spectral L/R fight |
| Mono close alone is dull | Tone / EQ / performance / prop choice | Not an L/R repair job |
When NOT to use PHIXER here
- You have not mono-auditioned close vs room yet.
- The fix is obviously polarity, delay, quieter close, or fewer library layers.
- You want PHIXER to make foley louder, wider, or "more cinematic." Wrong job.
- The SFX path is mono and the print problem is balance or EQ.
- See also when not to use PHIXER.
Quick path: Solo SFX in mono → polarity close vs room → delay-align close to room → pull close under hero room → simplify library layers → skip Haas/imagers → mono-check with dialogue → PHIXER only for leftover stereo cancellation on a bed → deliver clear labels + stem → fold again for LoRo/broadcast/phone.