PHIXER for radio broadcast mono fold: mono sum and phase cancellation
FM stereo, AM simulcast, and radio processors often sum L+R or treat the L-R difference as a fragile extra. Bass and voice that feel wide in headphones can cancel on mono radios, car speakers, and kitchen sets. Practical habit: true L+R sum on the production or delivery bus, then polarity and timing, then residual frequency-aware phase rotation only if a stereo bed must stay stereo. Check with free PHIXER before broadcast delivery, not only after a listener complaint. It is not a broadcast limiter, not an Orban / Omnia replacement, and not a substitute for a real mono listen on the delivery path.
Download PHIXER free YouTube tutorial YouTube intro
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 radio processor, not a time-aligner, not a stereo widener, and not a substitute for polarity, delay matching, or a true mono / FM fold-down check. Use it after hygiene, when residual spectral cancellation remains on a stereo bed you must keep stereo. Check with PHIXER before delivery.
Radio mono sum and phase cancellation (failure modes)
- Mono sum / L+R fold on air. Kick softens, bass thins, presenter voice hollows when FM, AM, or a processor folds. Habit: true L+R sum on the delivery or production bus before broadcast.
- Club / PA cousin. Dancefloor mono-sum is the same fold story as a radio processor. Cousin guide: PHIXER for Club System.
- Vinyl cut cousin. Same groove-friendly mono / bass-fold habit before lacquer. Cousin: PHIXER for Vinyl Cut / lacquer mono prep.
- Mastering chain cousin. Where phase check sits after EQ/compression and before limiter. Cousin: Where PHIXER sits in a mastering chain.
Fast radio broadcast mono audition (about 60 seconds)
- Sum L+R on the production bus, delivery bounce, or monitor controller mono. Listen to voice body, bass fundamental, and jingle mid. Do not mute one side to "hear the problem."
- A/B stereo vs mono. Note what disappears on fold: kick thump, sub, wide beds, stereo imaging on IDs.
- Mute wide FX / Haas / side-heavy verbs briefly. Note which path thins the radio fold.
- Confirm on a small speaker or single earbud (kitchen-radio / car-mono proxy), then again after any limiter / clipper / loudness pass.
- Only then audition residual L/R spectral fights with PHIXER if the stereo bed must stay stereo. Prove any change with mono A/B before delivery.
Honest order of fixes (before spectral phase rotation)
1. True mono / L+R listen on the delivery path
Hard L+R sum. Habit cousins: club system PA mono-sum and mono compatibility checklist.
2. Polarity if a path flips
Dual voice mics, music beds vs voice, layered IDs. Flip Ø when body returns. Guide: polarity invert vs continuous phase rotation.
3. Timing / delay-align before spectral tools
Nudge dual mics, beds, and dual-path music a few ms. Spectral rotation is not a substitute for timing.
4. Prefer correlated lows and voice for the air chain
Keep critical low-mid and presenter voice correlated. Put width in sides that survive fold. Related: vinyl cut prep and mastering chain placement.
5. Only then residual frequency-aware phase rotation
If a stereo bed must stay stereo and fold still hollows a band after the steps above, gentle rotation can help. Check with PHIXER before delivery. Prove it with mono A/B. Watch the YouTube tutorial and intro.
Radio / FM path types
| Setup | Common mono failure | First fix |
|---|---|---|
| FM stereo generator / L-R | Bass thin, voice soft on mono radios | True L+R listen before processor |
| AM simulcast / mono TX | Fine in stereo DAW, hollow on AM | Hard mono bounce check |
| On-air processor (Orban / Omnia class) | Studio thrill gone after AGC / clip | Re-check fold after processing, not only before |
| Car radio / kitchen speaker | Huge in headphones, gone in the car | Small-speaker proxy before delivery |
| Haas / wide ID beds under voice | Swish or cancel on fold | Less width in lows; correlated center |
| Club PA cousin of the same master | Fine on air, soft on dancefloor | Club system mono check |
| Mastering / delivery bounce | Phase check missed before limiter | Mastering chain placement |
| Vinyl cut of the radio master | Bass fold scoop before lacquer | Vinyl cut mono prep |
When not to reach for PHIXER
- Wrong polarity on one path (flip Ø first).
- Obvious attack misalignment (nudge first).
- You only need a mono-safe center print for AM / fold, not a stereo bus.
- AGC, clipper, or transmitter problems (wrong tool).
- Honesty list: When not to use PHIXER.
Related guides
- PHIXER for TV dialog / broadcast fold: mono fold and dialog intelligibility vs music beds
- PHIXER for Club System / PA mono-sum and phase before the dancefloor
- PHIXER for Vinyl Cut / lacquer mono prep (bass fold and phase before cut)
- Where PHIXER sits in a mastering chain
- PHIXER for Mono Compatibility Checklist
- Broadcast / radio / TV delivery mono
- When not to use PHIXER
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- Product
- Gumroad download
- YouTube tutorial · YouTube intro