PHIXER for Decca Tree: orchestral main array phase
A Decca Tree (L/C/R omnis or near-omnis on a T-bar, often with outriggers) can sound tall and deep in headphones: solid center, wide hall, natural bloom. On phone playback, Bluetooth, club PA mono, livestream fold, or a hall feed that goes LoRo, the middle thins and low-mid body dips while edges stay. Orchestral main-array stereo is not Mid/Side encoding, not a spaced pair alone, and not a widener. Polarity and a few samples of timing come first. Free phase-repair helps after residual L/R fights remain on a stereo bed you must keep stereo. It is not a Decca Tree decoder, not a microphone placer, and it does not replace a true mono listen.
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 tree-alignment tool, not a polarity button, not a delay matcher, and not a substitute for mono audition after a Decca Tree print. Use it after hygiene, when residual spectral cancellation remains on a stereo bed you must keep stereo.
Three Decca Tree / main-array failure modes this page covers
- L/C/R tree with a flipped or swapped capsule. One arm wired or oriented wrong can hollow the center in fold while stereo still sounds wide in cans.
- Tree print into Mid/Side or width tools. Encoding or widening a main-array bed can scoop Mid body on phone and club fold. Cousin: PHIXER for Mid-Side.
- Tree next to Blumlein, XY/ORTF/A-B, or outriggers. Stacking main arrays with coincident pairs, spaced pairs, or far outriggers piles more cancellation under fold. Cousins: Blumlein and Stereo Mic Pair.
Fast Decca Tree mono audition (about 60 seconds)
- Sum L+R with a monitor controller or utility. Do not mute the center mic to "hear the problem."
- A/B stereo vs mono across a sustained tutti and a transient attack. Note what disappears: center body, attack, hall tone, or image that was actually cancellation.
- Confirm L/C/R spacing, height, and that neither side arm is polarity-flipped by accident. Flip Ø on one channel if body returns immediately. Then nudge a few samples of L vs R attack timing before chasing plugins.
- Confirm on a phone speaker, then again after bus EQ / compressor / reverb send. Re-check after Mid/Side, width, Blumlein, mic-pair, or outrigger beds join the bus.
Honest order of fixes (before spectral phase rotation)
1. True mono listen on the Decca Tree print
Hard L+R sum with L/C/R open. Habit: mono check workflow.
2. Spacing and height before plugins
If mono scoops only when one arm drifts or the center is too hot, fix the tree first. Geometry mistakes are not free stereo.
3. Polarity before more processing
Flip Ø on one side arm while mono. Keep the flip that returns body. Guide: polarity vs phase.
4. Attack timing before spectral tools
Nudge a few samples or ms so transient peaks agree across L and R (and vs center if you fold C into the stereo bed). Often enough on phones and club fold even on trees that should already be time-aligned.
5. Skip when intentional thin mono is the point
Some Side-heavy tree prints are meant to stay edge-only in fold. Honesty list: When not to use PHIXER.
6. Only then audition residual L/R spectral fights
If a stereo Decca Tree 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.
Decca Tree setups and common mono failures
| Setup | Common mono failure | First fix |
|---|---|---|
| L/C/R omnis on a T-bar | Center body dips; edges stay | Mono listen; check Ø / spacing |
| Tree into M/S or widener | Mid scoops harder in fold | Mid-side use-case |
| Tree + Blumlein / XY / ORTF / A-B | Pair middle hollows on phone | Blumlein / Mic pair |
| Tree + outriggers / OH / room | Hall body scoops under close spots | Trim outriggers; mono check |
| One side arm wired reverse | Immediate center cancel in mono | Fix wiring; polarity flip |
| Master-bus width after tree | Streaming / phone fold thins | Mono check master; less width |
Mic pair, Blumlein, and Mid-side cousins (short version)
- Stereo mic pairs (XY, ORTF, A-B) share fold surprises with Decca Tree beds. Full write-up: PHIXER for Stereo Mic Pair.
- Blumlein coincident figure-8s often sit next to or instead of a tree in classical capture. Full write-up: PHIXER for Blumlein.
- Tree prints often meet Mid/Side matrices in classical, film score, and ensemble capture. Full write-up: PHIXER for Mid-Side.
- Polarity and attack timing still come first on every cousin. Spectral tools after residual L/R fights only.
When not to reach for PHIXER
- One tree arm or cable is simply wrong (fix the rig first).
- Wrong polarity on one channel (flip Ø first).
- Obvious attack misalignment (nudge first).
- You only need a mono-safe center print, not a stereo tree bed.
- Intentional Side-heavy texture that is meant to stay thin in mono.
- Honesty list: When not to use PHIXER.